促红细胞生成素与大鼠面神经损伤后运动神经元TNF-a及Bax的表达

This study sought to evaluate the effect of high-dose erythropoietin (EPO; 5 000 IU/kg) on the expression of tumor necrosis factor-alpha (TNF-α) and Bax in the facial nucleus after facial nerve transection in rats. A total of 42 Wistar rats of both genders were used in this study, and 40 rats were randomly divided into 2 groups: EPO group and model group. The EPO group was treated with EPO once a day for 5 days at a dose of 5 000 IU/kg body weight. The model group was treated with saline of the same amount. At day 3 after EPO (or saline) treatment, the right facial nerves of the 40 rats were transected at the level of the stylomastoid foramen, with the left sides untreated. The remaining 2 rats that did not undergo axotomy served as the control group. The surviving motor neurons in operated rats were counted in coronal paraffin sections of the facial nucleus. The expression of TNF-α and Bax in the facial nucleus was detected by immunohistochemical staining at days 3, 7, 14, 21, and 28 after axotomy. At days 14, 21, and 28 after facial nerve axotomy, a significantly greater proportion of facial motor neurons survived in the EPO group than in the model group. After axotomy, the expression of TNF-α and Bax increased in motor neurons in both the EPO and the model groups. TNF-α expression reached its peak level at day 14 after axotomy, while Bax expression reached its peak level at day 21. TNF-α expression was much lower in the EPO group than in the model group at all time points. No significant difference in Bax expression was found between the EPO and the model groups. These results indicate that high-dose EPO treatment attenuates the increase in TNF-α expression in the facial nucleus and reduces the loss of motor neurons after facial nerve transection in rats. However, high-dose EPO treatment has little effect on Bax expression.     

大鼠面神经切断和切断修复后面神经核内鞘脂激活蛋白原的变化

BACKGROUND： Studies have demonstrated that damaged facial nerves synthesize prosaposin to promote repair of facial neurons. OBJECTIVE： To observe time-course changes of prosaposin expression in the facial nerve nucleus of Sprague Dawley rats following facial nerve transection and repair. DESIGN, TIME AND SETTING： A randomized control neuropathological animal experiment was performed in Chongqing Medical University between March 2007 and September 2008. MATERIALS： A total of 48 adult, male, Sprague Dawley rats were selected and randomly divided into transection and transection ＋ end-to-end anastomosis groups （n =24）. Rabbit anti-rat prosaposin antibody, instant SABC immunohistochemical kit, and antibody dilution solution were purchased from Wuhan Uscn Science Co., Ltd., China. METHODS： In the transection group, the nerve trunk of the distal retroauricular branch of the left facial nerves was ligated in Sprague Dawley rats, and a 5-mm nerve trunk at the distal end of the ligation site was removed. In the transection ＋ end-to-end anastomosis group, epineurial anastomosis was performed immediately following transection of the left facial nerves. The right facial nerves in the two groups served as the normal control group. MAIN OUTCOME MEASURES： The number of prosaposin-positive neurons, as welt as intensity of immunostaining in facial nerve nucleus, following transection and end-to-end anastomosis were determined by immunohistochemistry at 1, 3, 7, 14, 21, and 35 days after injury. RESULTS： Transection group： transection of facial nerves resulted in increased number of prosaposin-positive neurons and immunoreactivity intensity in the facial nucleus on day 1. These values significantly increased by day 3. Expression was greater than in the control side. The peak of the reduction was reached at 7 days post-surgery. Transection ＋ end-to-end anastomosis group： the number of prosaposin-positive neurons and immunoreactivity intensity was reduced in the facial nerve nucleus following immediate end-to-end anastomosis on day 7 post-surgery. These values began to gradually increase by day 14 post-anastomosis. By day 35 post-anastomosis, the number of prosaposin-positive neurons in the operated side recovered to normal levels. The number of prosaposin-positive neurons, as well as immunoreactivity intensity, was significantly greater in the facial nerve nucleus, compared with the transection group on days 14, 21, and 35 post-surgery （P 〈 0.05）. The rhythmic whisking of vibrissa recovered, and recovery time was consistent with increased numbers of prosaposin-positive neurons. CONCLUSION： Within 7 days after injury, prosaposin expression in the facial nerve nucleus exhibited an initial increase, followed by a decrease, and was not affected by facial nerve repair. Following facial nerve damage, neural anastomosis was shown to increase prosaposin expression in the facial nerve nucleus after 14 days. Recovery of prosaposin occurred simultaneously with reinnervation.     

Neuroprotective effects of recombinant human erythropoietin on facial motoneurons after facial nerve injury in rats★

BACKGROUND： Erythropoietin and recombinant human erythropoietin （rhEPO） inhibit apoptosis of motor neurons caused by spinal cord injury and brain damage in rats. However, it still remains to be shown whether rhEPO can protect facial motoneurons （FMNs） as Well. OBJECTIVE： To test the neuroprotective effects of rhEPO on injured VMNs, as well as the influence on Caspase-3 expression. DESIGN, TIME AND SETTING： Randomized, controlled, animal experiment. This study was performed at the Central Laboratory of Basic Medical College, Chongqing Medical University from January to October 2007. MATERIALS： Seventy-five female SD rats, weighing 210-230 g. rhEPO injection was provided by Sansheng pharmaceuticals company, Shenyang City, Liaoning Province, China, and the License number was HMLN S20010001. METHODS： A total of 75 female rats were randomly divided into rhEPO treatment, control, and sham operation groups, with 25 rats in each group. Rat models of facial nerve injury were established in the rhEPO treatment group and the control group by crushing the main trunk of the left facial nerve. Surgical microscopic observation of the facial nerve damage displayed perineurial disruption. The left stylomastoid foramen of the sham operation group were only exposed, but without nerve injury. The rhEPO treatment group was treated with rhEPO （5 000 U/kg, i.p.） once following injury and once a day for two weeks. The control and sham operation groups were treated with the same dose of normal saline （i.p.）, once following injury and once a day for two weeks. MAIN OUTCOME MEASURES： Rats were sacrificed 3, 7, 14, 21, and 28 days after injury, FMN survival after facial nerve injury was analyzed by Toluidine blue staining, and then survival ratios （L/R） were calculated. The number of apoptotic profiles in the injured FMNs were evaluated by TUNEL staining. Expression of Caspase-3 in the facial nucleus was detected by immunohistochemistry methods. RESULTS： A total of 75 rats were included in the final analysi     

Acute pathological changes of facial nucleus and expressions of postsynaptic density protein-95 following facial nerve injury of varying severity★ A semi-quantitative analysis

BACKGROUND： Previous studies have demonstrated that postsynaptic density protein-95 （PSD-95） is widely distributed in the central nervous system and is related to the development of the CNS and sensory signal transmission as well as acute or chronic nerve cell death following ischemic brain injury. OBJECTIVE： To semi-quantitatively determine the pathological changes of apoptotic facial neurons and the expression of PSD-95 in the facial nucleus following facial nerve injury of varying extents using immunohistochemical staining methods. DESIGN, TIME AND SETTING： Randomized, controlled animal experiments were performed in the Ultrasonic Institute of the Second Affiliated Hospital of Chongqing University of Medical Sciences from September to December 2007. MATERIALS： Sixty-five healthy, adult, Sprague-Dawley （SD） rats, both male and female, were used for this study. Rabbit anti-rat PSD-95 polyclonal antibody was purchased from Beijing Biosynthesis Biotechnology Co., Ltd. METHODS： SD rats were randomly assigned into a control group with five rats and three injured groups with 20 rats per group. Exposure, clamp and cut for bilateral facial nerve trunks were performed in the rats of the injury groups, and no injury was inflicted on the rats of the control group. MAIN OUTCOME MEASURES; The brainstems of all the rats were excised on days 1, 3, 7, and 14 post injury, and then the facial nuclei were stained with hematoxylin-eosin to observe any pathological changes due to apoptosis in facial neurons. PSD-95 expression in facial nuclei was detected by immunohistochemistry and the number of PSD-95 positive cells was counted under a light microscope. RESULTS： The expression of PSD-95 in the facial nucleus and morphology of the facial neuron within the exposure group had no obvious changes at various points in time tested （P 〉 0.05）. However, the expressions of PSD-95 in the facial nucleus of the clamp group and cut group increased on day 1 post injury （P 〈 0.05）, and showed further increase on d     

Acupuncture at Baihui and Dazhui reduces brain cell apoptosis in heroin readdicts简

Acupuncture at Baihui （GV20） and Dazhui （GV14） reduces neuronal loss and attenuates ultra- structural damage in cerebral ischemic rats. However, whether acupuncture can treat addiction and prevent readdiction through changes to brain cell ultrastructure remains unknown. In this study, cell apoptosis was observed in the hippocampus and frontal lobe of heroin readdicted rats by electron microscopy. Immunohistochemical staining displayed a reduction in Bcl-2 ex- pression and an increase in Bax expression in the hippocampus and frontal lobe. After rats were given acupuncture at Baihui and Dazhui, the pathological damage in the hippocampus and frontal lobe was significantly reduced, Bcl-2 expression was upregulated and Bax expression was downregulated. Acupuncture exerted a similar effect with methadone, a commonly used drug for clinical treatment of drug addiction. Experimental findings suggest that acupuncture at Dazhui and Baihui can prevent brain cell apoptosis in heroin readdicted rats.     

Correlation of brain-derived neurotrophic factor to cognitive impairment following traumatic brain injury in rats**☆

BACKGROUND： In vitro and in vivo studies have confirmed that brain-derived neurotrophic factor （BDNF） can promote survival and differentiation of cholinergic, dopaminergic and motor neurons, and axonal regeneration. BDNF has neuroprotective effects on the nervous system. OBJECTIVE： To explore changes in BDNF expression and cognitive function in rats after brain injury. DESIGN, TIME AND SETTING： The neuropathology experiment was performed at the Second Research Room, Department of Neurosurgery, Fujian Medical University （China） from July 2007 to July 2008. MATERIALS： A total of 72 healthy, male, Sprague Dawley, rats were selected for this study. METHODS： Rat models of mild and moderate traumatic brain injury were created by percussion, according to Feeney＇s method （n = 24, each group）. A bone window was made in rats from the sham operation group （n = 24）, but no attack was conducted. MAIN OUTCOME MEASURES： At days 1, 2, 4 and 7 following injury, BDNF expression in the rat frontal lobe cortex, hippocampus and basal forebrain was examined by immunohistochemistry （streptavidin-biotin-peroxidase complex method）. Changes in rat cognitive function were assessed by the walking test, balance-beam test and memory function detection. RESULTS： Cognitive impairment was aggravated at day 2, and recovered to normal at days 3 and 7 in rats from the mild and moderate traumatic brain injury groups. BDNF expression in the rat frontal lobe cortex, hippocampus and basal forebrain was increased at 1 day, decreased at day 2, and then gradually increased in the mild and moderate traumatic brain injury groups. BDNF expression was greater in rats from the moderate traumatic brain injury group than in the sham operation and mild traumatic brain injury groups （P 〈 0.05）. CONCLUSION： BDNF expression in the rat frontal lobe cortex, hippocampus and basal forebrain is correlated to cognitive impairment after traumatic brain injury. BDNF has a protective effect on cognitive function in rats following i     

Influence of ginsenoside on expression of brain-derived neurotrophic factor and receptor tyrosine kinase B in the medial septum of aged rats★

BACKGROUND： It has beenshown that ginsenoside, the effective component of ginseng, can enhance expression of choline acetyl transferase, as well as brain-derived neurotrophic factor （BDNF） and its receptor tyrosine kinase B （TrkB）, in cholinergic neurons of the basal forebrain. OBJECTIVE： To qualitatively and quantitatively verify the influence of ginsenoside on expression of BDNF and its receptor, TrkB, in the medial septum of aged rats, and to provide a molecular basis for clinical application. DESIGN~ TIME AND SETTING： A contrast study, which was performed in the Department of Anatomy, China Medical University, and the Department of Anatomy, Shenyang Medical College between December 2005 and May 2007. MATERIALS： Thirty-five, healthy, female, Sprague Dawley rats were selected for this study. Ginsenoside （81% purity） was provided by Jilin Ji＇an Wantai Chinese Medicine Factory; anti-BDNF antibody, anti-TrkB antibody, and their kits were provided by Wuhan Boster Company. METHODS： A total of 35 rats were divided into three groups： young （four months old）, aging （26 months old）, and ginsenoside. Rats in the ginsenoside group were administered ginsenoside （25 mg/kg/d） between 17 months and 26 months. MAIN OUTCOME MEASURES： Immunohistochemistry and in situ hybridization were used to measure expression of BDNF and TrkB in the medial septum of aged rats, and the detected results were expressed as gray values. RESULTS： （1） Qualitative detection： using microscopy, degenerative neurons were visible in the medial septum in the aging group. However, neuronal morphology in the ginsenoside group was similar to neurons in the young group. （2） Quantitative detection： the mean gray value of BDNF-positive and TrkB-positive products in the aging group were significantly higher than in the young group （t = 3.346, 4.169, P 〈 0.01）; however, the mean gray value in the ginsenoside group was significantly lower than in the aging group （t = 2.432, 2.651, P 〈 0.01）. CONCLUS     

p75 neurotrophin receptor signal pathway influence on apoptosis in anterior horn neurons of the spinal cord in a rat model of cauda equina compression injury

BACKGROUND： Studies have demonstrated that cauda equina compression results in apoptosis of motor neurons in the spinal cord. The combination of p75 neurotrophin receptor （p75NTR） and precursor of nerve growth factor （pro-NGF） expression initiates the apoptotic pathway and induces neuronal apoptosis. However, few reports have focused on the p75-mediated mechanism of neuronal apoptosis following cauda equine compression injury OBJECTIVE： To determine apoptosis of spinal cord neurons and activation of the pro-NGF-p75NTR-JNK（c-Jun N-terminal kinase） signal pathway in rats following cauda equina compression, and to verify experimental outcomes. DESIGN, TIME AND SETTING： A randomized, controlled, in vivo experiment was performed at the Medical Experimental Center of Xi＇an Jiaotong University between April and November in 2008. MATERIALS： Streptavidin-perosidase kit was purchased from Wuhan Boster, China; in situ end labeling detection kit was provided by Promega, USA; type AEG-220G electron microscope was purchased from Hitachi, Japan. METHODS： A total of 48 healthy, adult, female, Sprague Dawley rats were randomly assigned to three groups： normal （n = 6）, sham-surgery （n = 6）, and compression （n = 36）. The compression group was randomly assigned to six subsets at 1,3, 5, 7, 14, and 28 days, respectively, with 6 rats in each subset. A cylindrical silica gel stick was implanted into the rats to compress 75% of the vertebral canal in the compression group; in the sham-surgery group, only vertebral resection was performed; and no procedures were performed in the normal group. MAIN OUTCOME MEASURES： At 1,3, 5, 7, 14, and 28 days following compression, L2-3 spinal cord segments were processed for immunohistochemistry, in situ cell apoptosis detection, and transmission electron microscopy observation. Nissl staining was used to observe neuronal survival in the L2 spinal cord segment. Immunohistochemistry was applied to detect expressions of pro-NGF, p75NTR, and JNK in the L2 segment. TUNEL fluorometric method was used to observe apoptosis of neurons in the L2 segment. RESULTS： In the normal and sham-surgery groups, little neuronal apoptosis was observed in the L2-3 spinal cord segment. At 3 days after compression injury, pro-NGF, p75NTR and JNK expression was observed in the spinal cord. Expression levels reached a peak at 7 days, and then gradually decreased. In the compression and sham-surgery groups, neurons primarily expressed pro-NGF and p75NTR. The number of JNK-positive neurons in the compression group was dramatically increased compared with the sham-surgery group （P〈 0.05）. A few neurons were apoptotic in the spinal cord 1 day after compression injury. The number of apoptotic neurons gradually increased and reached a peak at 7 days, and subsequently decreased. Apoptosis was still detectable at 28 days. There was a positive correlation between p75NTR expression and neuronal apoptosis （r= 0.75, P〈 0.05）. CONCLUSION： Following cauda equina compression injury, apoptosis of spinal cord neurons was observed. The compression-induced neuronal apoptosis was associated with p75NTR expression in the L2-3 spinal cord segment.     

Effects of Ginsenoside Rgl on nuclear factor-kappa B activity in beta amyloid protein-treated neural cells

BACKGROUND： Modern pharmacological studies have shown that Ginsenoside Rgl is one of the active components of ginseng that promote intelligence in the nervous system. Ginsenoside Rgl can improve memory and learning in mouse models of β-amyloid protein （Aβ）-induced dementia. OBJECTIVE： To investigate whether effects of Ginsenoside Rgl against Aβ are associated with activity of nuclear factor-kappa B （NF-κB）. DESIGN, TIME AND SETTING： The randomized performed at the DME Center, Institute of Clinica controlled, cell biological experiment was Pharmacology, Guangzhou University of Chinese Medicine, China from July 2005 to May 2006. MATERIALS： Beta-amyloid fragment 25-35 （Aβ25-35） was supplied by the Neural Biochemical Laboratory, Xuanwu Hospital, Capital Medical University, China. Ginsenoside Rgl was obtained from National Institute for the Control of Pharmaceutical and Biological Products, China. Rabbit anti-rat NF-κB p65 antibody was purchased from Santa Cruz Biotechnology, USA. METHODS： Hippocampal neurons and cortical astrocytes of neonatal Sprague Dawley rats were harvested and treated with various concentrations （0, 5, 10, 20, and 40 μmol/L） of Aβ for 6, 12, and 24 hours to establish cellular models of Alzheimer＇s disease. Cellular models were pretreated with various concentrations of Ginsenoside Rgl （1,2, 4, 8, and 16 μmol/L）. According to cell morphology and activity, the following conditions were selected： 40 μmol/L Aβ for 24 hours, as well as 2, 4, and 8 μmol/L Ginsenoside Rg1. NF-κB activity was observed using immunofluorescence and cytochemical staining. MAIN OUTCOME MEASURES： Morphology and viability of hippocampal neurons and cortical astrocytes, and activities of NF-κB were measured. RESULTS： Hippocampal neuron activity was significantly greater in the normal and 2 and 4 μmol/L Ginsenoside Rgl groups compared with the model group （P 〈 0.05）. Astrocyte activity was significantly greater in the normal, 1,2, 4, 8, and 16 μmol/L Ginsenoside Rgl groups compared with the model group （P 〈 0.05）. NF-κB activity of hippocampal neurons was significantly greater in the normal, 2, 4, and 8 μmol/L Ginsenoside Rgl groups compared with the model group （P 〈 0.01）. NF-κB activity of astrocytes was significantly less in the normal, 2, 4, and 8 μmol/L Ginsenoside Rgl groups compared with the model group （P 〈 0.01 or P 〈 0.05）. No significant difference in NF-κB activity was determined between the 2 μmol/L Ginsenoside Rgl and normal groups （P 〉 0.05）. CONCLUSION： Ginsenoside Rgl protected neural cells by upregulating NF-κB activity in neurons and downregulating NF-κB activity in astrocytes. Ginsenoside Rgl （2 μmol/L） maintained cell activity and NF-κB activity at normal levels.     

Anti-apoptotic effects of aspirin following cerebral ischemia-reperfusion injury in rats☆

BACKGROUND： The pharmacological effects of aspirin on apoptosis are complex. The underlying mechanisms have not been properly defined. OBJECTIVE： To observe the effect of different doses of aspirin on brain cell apoptosis following focal cerebral iscbemia-reperfusion injury （CIRI） in rats. DESING, TIME AND SETTING： A randomized, controlled, animal experiment, performed at the School of Medicine and Pharmaceutics, Jiangnan University between June and October 2006. MATERIALS： Twenty-six male, adult, Sprague Dawley rats （grade Ⅱ）, weighing 240-290 g, were obtained from Shanghai Experimental Animal Center, Chinese Academy of Sciences. Aspirin was provided by Sigma （USA）. METHODS： The rats were randomly divided into four groups： sham-operation （SO）, CIRI ＋ vehicle, CIRI ＋ aspirin （6 mg/kg）, and CIRI ＋ aspirin （60 mg/kg）. Rats in the lesion groups were intragastrically administrated saline, aspirin （6 mg/kg）, or aspirin （60 mg/kg）, respectively. MAIN OUTCOME MEASURES： The number of pyramidal neurons with normal appearance in the cerebral cortex at 24 mm from the midline; apoptotic cell death as measured by TUNEL; Bcl-2 and Bax protein localization was determined by immunohistochemistry; malondialdehyde （MDA） and super oxidation （SOD） content were determined by biochemistry method; adenosine triphosphate （ATP） content measured by capillary electrophoresis. RESULTS： Following CIRI, the following parameters were altered compared with sham-operated animals： the number of neurons with normal appearance was significantly reduced in the cerebral cortex; the number of apoptotic cells increased; Bax protein expression was enhanced; and the ratio between Bcl-2 and Bax decreased. In addition, MDA content increased significantly, whereas ATP content decreased （P 〈 0.01）. Aspirin ameliorated the loss of healthy pyramidal neurons. Both 6 and 60 mg/kg aspirin increased the ratio between Bcl-2 and Bax, with no significant difference between the treatment group     

Hippocampal CA1 pyramidal cells and neurotrophic factors in a rat model of vascular dementia following Xiongma drop pill versus Ginkgo leaf tablets

BACKGROUND： Previous studies have demonstrated the neuroprotective effects of Xiongma drop pill （XMDP） in a mouse model of vascular dementia. Neurotrophic factors play an important role in repair and regeneration of injured neurons. OBJECTIVE： To compare the effects of XMDP and Ginkgo leaf tablets on the appearance and number of hippocampal CA1 pyramidal neurons, as well as neurotrophic factor content in brain tissues, during vascular dementia formation to explore the neuroprotective mechanisms of XMDP. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment was performed at the Laboratory of Pharmacology, College of Pharmacy, Harbin University of Commerce between April 2007 and December 2008. MATERIALS： XMDP was prepared by the College of Pharmacy, Harbin University of Commerce, with each 40 mg pill containing ferulic acid （≥ 0.149 mg） and gastrodin （≥ 0.171 mg）. Ginkgo leaf tablets were purchased from Taiyuan Qianyuan Pharmacy, China. METHODS： Healthy, adult, male, Wistar rats were randomly assigned to 6 groups： sham-operation, model, XMDP （high-, middle-, and low- dose）, and Ginkgo leaf tablets. The 6 groups were subdivided into two subgroups according to administration days, i.e., 30 and 60 days, with 8 animals in each subgroup. Rats in the model, XMDP, and Ginkgo leaf tablets groups were subjected to permanent bilateral ligation of the common carotid artery to establish a vascular dementia model. At 8 days after model establishment, all groups received intragastric administration once daily of the following： 10 mL/kg normal saline in the sham-operation and model groups; 0.4, 0.2, and 0.1 g/kg XMDP in the high-, middle-, and low-dose XMDP groups, respectively; and 50 mg/kg Ginkgo leaf tablets in the Ginkgo leaf tablets group. MAIN OUTCOME MEASURES： Hematoxylin-eosin staining was used to observe appearance and to quantify the number of hippocampal CA1 pyramidal neurons. Brain-derived neurotrophic factor and nerve growth factor concentrations in brain tissues were detected by enzyme-linked immunosorbent assay. RESULTS： Following model establishment, hippocampal CA1 neurons exhibited pathological changes. Compared with the sham-operation group, the number of pyramidal neurons significantly decreased （P 〈 0.05 or P 〈 0.01）, and neurotrophic factor concentration increased in the model rats （P 〈 0.05 or P 〈 0.01）. XMDP attenuated neuronal injury in a dose-dependent manner： the number of pyramidal neurons and neurotrophic factor concentrations were significantly increased compared with the model group （P〈 0.05 or P〈 0.01）. High- and middle-dose XMDP resulted in equivalent effects to Ginkgo leaf tablets. In addition, neurotrophic factor concentrations in all XMDP groups, after 60 days of administration, were remarkably greater than corresponding concentrations at 30 days （P 〈 0.05 or P 〈 0.01 ）. CONCLUSION： Hippocampal CA1 pyramidal cells exhibited pathological injury following establishment of the vascular dementia model. Middle- and high-dose XMDP increased neurotrophic factor expression in the brain of vascular dementia rats, which suggested neuroprotection equivalent to Ginkgo leaf tablets.     

MiR-206 decreases brain-derived neurotrophic factor levels in a transgenic mouse model of Alzheimer＇s disease

MicroRNA alterations have been reported in patients with Alzheimer＇s disease （AD） and AD mouse models. We now report that miR-206 is upregulated in the hippocampal tissue, cerebrospinal fluid, and plasma of embryonic APP/PS1 transgenic mice. The increased miR-206 downregulates the expression of brain-derived neurotrophic factor （BDNF）. BDNF is neuroprotective against cell death after various insults, but in embryonic and newborn APP/PS1 mice it is decreased. Thus, a specific microRNA alteration may contribute to AD pathology by downregulating BDNF.     

转化生长因子β和脑源性神经营养因子联合诱导成年大鼠骨髓基质细胞向神经元样细胞的分化

BACKGROUND： It has been demonstrated that transforming growth factor-β （TGF-β） and brain- derived neurotrophic factor （BDNF） can induce stem cell differentiation into neuron-like cells. OBJECTIVE： To investigate the efficacy of TGF-β and BDNF at inducing the differentiation of adult rat bone marrow stromal cells （BMSCs） into neuron-like cells, both in combination or alone. DESIGN, TIME AND SETTING： A comparative observation experiment was performed at the Department of Orthopedics, First Affiliated Hospital of Liaoning Medical University between October 2007 and January 2008. MATERIALS： TGF-~ and BDNF were purchased from Sigma, USA; mouse anti-rat neuron specific enolase, neurofilament and glial fibrillary acidic protein were purchased from Beijing HMHL Biochem Ltd., China. METHODS： BMSCs were isolated from rats aged 4 weeks and incubated with TGF-β（1μ g/L） and/or BDNF （50 μ g/mL）. MAIN OUTCOME MEASURES： Expression of neuron-specific enolase, neurofilament and glial fibrillary acidic protein were determined by immunocytochemistry. RESULTS： BMSCs differentiated into neuron-like cells following induction of TGF-β and BDNF, and expressed both neuron-specific enolase and neurofilament. The percent of positive cells was significantly greater in the combination group than those induced with TGF-β or BDNF alone （P 〈 0.01）. CONCLUSION： Treatment of BMSCs with a combination of TGF-β and BDNF induced differentiation into neuron-like cells, with the induction being significantly greater than with TGF-β or BDNF alone.     

Association of single nucleotide polymorphisms of brain-derived neurotrophic factor gene and multidrug resistance 1 gene to refractory epilepsy in Chinese Han children

BACKGROUND： There are two hypotheses for the underlying cause of refractory epilepsy： ＂target＂ and ＂transport＂. Studies have shown that brain-derived neurotrophic factor （BDNF） is over-expressed in refractory epilepsy. Multidrug resistance 1 （MDR1） gene encodes for P-glycoprotein, the primary ATP-binding cassette transporter in the human body. Some single nucleotide polymorphisms of the MDR1 gene have been associated with refractory epilepsy. OBJECTIVE： To investigate the association between BDNF gene C270T polymorphism and MDR1 T-129C polymorphism with refractory epilepsy in Chinese Han children through the use of polymerase chain reaction （PCR）-restriction fragment length polymorphism analysis. DESIGN, TIME AND SETTING： A case-control, genetic association study was performed at the Central Laboratory, Third Xiangya Hospital of Central South University from June 2005 to November 2007. PARTICIPANTS： A total of 84 cases of unrelated children with epilepsy, including 41 cases of refractory epilepsy and 43 cases of drug-responsive epilepsy, were enrolled. An additional 30 healthy, Chinese Han children, whose ages and gender matched the refractory epilepsy patients, were selected as normal controls. METHODS： Venous blood was collected and genomic DNA was extracted from the blood specimens. C270T polymorphism in BDNF gene and T-129C polymorphism in MDR1 gene were genotyped using PCR-restriction fragment length polymorphism analysis. Association analysis using the Ftest and Chi-square test was statistically performed between C270T polymorphism in BDNF gene and T-129C polymorphism in MDR1 gene and refractory epilepsy. MAIN OUTCOME MEASURES： The distribution of genotypes and allele frequencies of C270T polymorphism in BDNF gene and T-129C polymorphism in MDR1 gene. RESULTS： The distribution of CC, CT, and TT genotypes, as well as C and T allele frequencies, in the BDNF gene was not significantly different between the refractory epilepsy group, drug-responsive epilepsy group, or the normal control group （P 〉 0.05）. The distribution of TT genotype and T allele frequencies of the MDR1 gene was significantly different in the refractory epilepsy group compared with the drug-responsive epilepsy and normal control groups （P 〈 0.05）. Comparison of haplotype combinations demonstrated that there were no significant differences in combinations of TT＋CC, -FI-＋CT, TC＋CC, and TC＋CT among the three groups （P 〉 0.05）. CONCLUSION： C270T polymorphism of the BDNF gene was not associated with refractory epilepsy in Chinese Han children, but T-129C polymorphism in the MDR1 gene was associated with refractory epilepsy in Chinese Han children. The TT genotype and T allele frequencies could serve as susceptibility loci for refractory epilepsy. Interactions between C270T in BDNF gene and T-129C in MDR1 gene were not observed in refractory epilepsy in Chinese Han children.     

Environmental factors in the development and progression of late-onset Alzheimer＇s disease

Late-onset Alzheimer＇s disease （LOAD） is an age-related neurodegenerative disorder characterized by gradual loss of synapses and neurons, but its pathogenesis remains to be clarified. Neurons live in an environment constituted by neurons themselves and glial cells. In this review, we propose that the neuronal degeneration in the AD brain is partially caused by diverse environmental factors. We first discuss various environmental stresses and the corresponding responses at different levels. Then we propose some mechanisms underlying the specific pathological changes, in particular, hypothalamic-pituitary adrenal axis dysfunction at the systemic level; cerebrovascular dysfunction, metal toxicity, glial activation, and Aβ toxicity at the intercellular level; and kinase-phosphatase imbalance and epigenetic modification at the intracellular level. Finally, we discuss the possibility of developing new strategies for the prevention and treatment of LOAD from the perspective of environmental stress. We conclude that environmental factors play a significant role in the development of LOAD through multiple pathological mechanisms.     

Effects of brain-derived neurotrophic factor on induced differentiation of SH-SY5Y cells in vitro

BACKGROUND： Previous studies have demonstrated that brain-derived neurotrophic factor （BDNF） promotes neural differentiation. However, the mechanisms involved in cell cycle-related protein regulation, which highly correlates to neural proliferation and apoptosis, remain poorly understood. OBJECTIVE： To investigate the effects of various concentrations of BDNF on cycle-related protein mRNA expression in induce-differentiated SH-SY5Y cells in vitro prior to and following G2 phase, and to analyze the neuroprotective effects of BDNF. DESIGN, TIME AND SETTING： A comparison, observational study, based on cell biology, was performed at the Department of Biochemistry, Medical College of Tongji University, from March 2005 to October 2006. MATERIALS： SH-SY5Y cells were provided by Shanghai Institute of Cytology, Chinese Academy of Science; BDNF by Alomone Labs, Israel; all-trans retinoic acid （ATRA） by Sigma-Aldrich, USA. METHODS： SH-SY5Y cells were randomly divided into three groups： blank control [cells were treated in Insulin-Transferrin-Selenium （ITS） solution for 7 days], ATRA （cells were treated with ITS solution containing 10 μmol/L ATRA for 7 days）, and BDNF （cells were treated identical to the ATRA group for 5 days, and then respectively treated in ITS solution containing 1, 10, and 100 μg/L BDNF for 2 days）. The experiment was repeated three times for each group. MAIN OUTCOME MEASURES： mRNA expression levels of cyclin A1, B1, B2, cyclin-dependent kinase 1, and 5 were detected using quantitative real-time RT-PCR; percentage of cells in G1, S, and G2 phases were detected using fluorescence-activated cell sorting. RESULTS： mRNA expression levels of cyclin A1 in the high-dose BDNF group was significantly less than the ATRA group （P 〈 0.05）.mRNA expression levels of cyclin B1 was significantly less in the different BDNF concentration groups compared with the control and ATRA groups （P 〈 0.05 or P 〈 0.01）. mRNA expression levels of cyclin B2 and cyclin-dependent kinase 1 were significantly decreased in the high-dose BDNF group （P 〈 0.05 or P 〈 0.01）. Cyclin-dependent kinase 5 mRNA expression was significantly greater in the low-dose and moderate-dose BDNF groups compared with the ATRA group （P 〈 0.05）. The percentage of cells in G1 phase was significantly greater in the different BDNF concentration groups compared with the ATRA and control groups （P 〈 0.01）. Moreover, the percentage of cells in S phase was significantly less in the three BDNF groups compared with the ATRA group （P 〈 0.01）. However, the percentage of cells in S phase was significantly less in the low-dose and high-dose BDNF groups compared with the control group （P 〈 0.01）. CONCLUSION： BDNF enhanced the percentage of cells in G1 phase, but did not alter mRNA expression of cell cycle-related proteins prior to or following G2 phase. These results suggested that BDNF was not a risk factor for inducing apoptosis.     

高血压脑出血的显微外科治疗进展

高血压脑出血（Hypertensive intrac-rebral hemorrhage,HICH）是具有高发病率、高病死率、高致残率的急性脑血管疾病,占所有脑卒中患者的10%-20%,早期病死率可高达49.4%。随着人口老龄化,其发病率逐年提高;而外科手术的干预,使其病死率有所下降,但致残率居高不下。如何提高手术疗效和患者生存质量,一直是神经外科医师努力的方向。微侵袭血肿清除术因其手术创伤小,恢复快,是目前国内治疗高血压脑出血的重要手段。     

神经内镜联合亚低温治疗高血压基底节区脑出血

目的 探讨神经内镜联合亚低温在治疗高血压基底节区脑出血中的临床应用价值.方法 回顾性分析我院神经内镜治疗高血压基底节区脑出血患者40例的临床资料,并对治疗结果进行分析.结果 神经内镜治疗组22例(甲组),神经内镜联合亚低温治疗组18例(乙组),术后3个月根据GCS评分,甲组恢复良好1例,中残4例,重残6例,植物生存6例,死亡5例;乙组恢复良好4例,中残8例,重残3例,植物生存1例,死亡2例,两组比较差异有统计学意义(P＜0.05).两组颅内压比较第1天两者差异不明显,但第2、3天亚低温组颅内压明显降低.结论 神经内镜是治疗高血压基底节区脑出血较为有效的手术方式,联合亚低温治疗能有效降低颅内压,改善术后神经功能恢复,具有较好的临床应用价值.     

Targeting 13-secretase with RNAi in neural stem cells for Alzheimer＇s disease therapy

There are several major pathological changes in Alzheimer＇s disease, including apoptosis of cho- linergic neurons, overactivity or overexpression of 13-site amyloid precursor protein cleaving enzyme 1 （BACE1） and inflammation. In this study, we synthesized a 19-nt oligonucleotide targeting BACE1, the key enzyme in amyloid beta protein （AI3） production, and introduced it into the pSilenCircle vector to construct a short hairpin （shRNA） expression plasmid against the BACE1 gene. We transfected this vector into C17.2 neural stem cells and primary neural stem cells, resulting in downregulation of the BACE1 gene, which in turn induced a considerable reduction in reducing AI3 protein production. We anticipate that this technique combining cell transplantation and gene ther- apy will open up novel therapeutic avenues for Alzheimer＇s disease, particularly because it can be used to simultaneously target several pathogenetic changes in the disease.