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     

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.     

Co-expression of calretinin and parvalbumin in the rat facial nucleus**★

BACKGROUND： Calretinin and parvalbumin are members of the intracellular calcium binding protein family, which transform Ca^2＋ bioinformation into regulation of neuronal and neural network activities. OBJECTIVE： To observe expression and co-expression of calretinin and parvalbumin in rat facial nucleus neurons . DESIGN, TIME AND SETTING： Neuronal morphology experiment was performed at the Research Laboratory of Applied Anatomy, Department Neurobiology and Anatomy, Xiangya Medical College of Central South University from August to October 2007. MATERIALS： Five healthy, adult Sprague Dawley rats were selected. Polyclonal rabbit-anti-parvalbumin and mouse-anti-calretinin were provided by Sigma, USA. METHODS： Rat brains were obtained and cut into coronal slices using a freezing microtome. Slices from the experimental group were immunofluorescent stained with polyclonal rabbit-anti-parvalbumin and mouse-anti-calretinin antibodies. The control group sections were stained with normal rabbit and mouse sera. MAIN OUTCOME MEASURES： Immunofluorescent double-staining was used to detect calretinin and parvalbumin expression. Nissl staining was utilized for facial nucleus localization and neuronal morphology analysis. RESULTS： The majority of facial motor neurons was polygon-shaped, and expressed calretinin and parvalbumin. The calretinin-immunopositive neurons also exhibited parvalbumin immunoreactivity, that is, calretinin and parvalbumin were co-expressed in the same neuron. CONCLUSION： Calretinin and parvalbumin were expressed in facial nucleus neurons, with varied distribution.     

人参皂甙Rg1对去卵巢大鼠面神经核脑源性神经营养因子表达的影响：半定量分析

BACKGROUND： Estrogen is neuroprotective effects such as breast carcinoma, endometria but long-term estrogen treatment can induce side cancer, and stroke. However, phytoestrogen is neuroprotective without these side effects. OBJECTIVE： To study the effects of Ginsenoside Rgl on facial neurons and brain-derived neurotrophic factor （BDNF） expression in the facial nucleus in ovariectomized rats. DESIGN, TIME AND SETTING： The randomized, controlled animal experiments were performed at the Ultrasonic Institute, Second Affiliated Hospital, Chongqing Medical University, China, from September 2007 to September 2008. MATERIALS： Ginsenoside Rgl （Sigma, USA）, rabbit anti-rat BDNF, Bcl-2, Bax antibodies, biotin-labeled goat anti-rabbit IgG （Boster, China）, and a TUNEL kit （Roche, Germany） were used in this study. METHODS： A total of 48 adult Sprague Dawley rats undergoing ovariectomy were randomly assigned into sham operation （n = 8）, model （n = 20）, and Ginsenoside Rgl （n = 20） groups. Facial nerve damage was induced by bilateral clamping of the facial nerve trunk. The bilateral facial nerve trunk was exposed in the sham operation group, with no clamping. Rats in the Ginsenoside Rgl group were intraperitoneally injected with 10 mg/kg per day Ginsenoside Rgl; other groups received 2 mL saline, once a day, for 14 days. MAIN OUTCOME MEASURES： Morphologic changes in neurons of the facial nucleus were observed following hematoxylin-eosin staining. Neuronal apoptosis was detected by TUNEL. Changes in ultrastructure of the facial nerve fibers were observed with a transmission electron microscope. Expression of BDNF, Bcl-2, and Bax protein was quantified by semiquantitative immunohistochemistry. RESULTS： At 3-14 days following facial nerve damage, Ginsenoside Rgl increased BDNF expression and the number of regenerated nerve fibers, and produced thicker myelin sheaths （P 〈 0.05）. Ginsenoside Rgl also gradually increased Bcl-2 protein expression and decreased Bax protein expression （P 〈 0.05）. By day 7, apoptosis was observed in facial neurons, but Ginsenoside Rgl reduced the number of apoptotic neurons. Sham animals did not show any changes in BDNF, Bcl-2, or Bax expression or facial neuron morphology. CONCLUSION： Ginsenoside Rgl can substantially inhibit facial neuronal apoptosis by increasing endogenous BDNF and Bcl-2 expression and by decreasing Bax expression in ovariectomized rats after facial nerve damage.     

Effect of Panaxtriol Saponins on synaptophysin and postsynaptic density-95 expression at different periods of cerebral infarction*☆

BACKGROUND： The change in expression of synaptophysin （Syp） and postsynaptic density-95 （PSD-95） alters after cerebral infarction, and the plasticity of synapses contributes greatly to nerve function recovery. Chinese medicinal substances may play an important role in the expression of Syp and PSD-95. OBJECTIVE： To observe the effect of Panaxtriol Saponins （PTS）, an active component in Sanqi tongshu capsules, on the expression of Syp and PSD-95 after cerebral infarction at different time points in rats, so as to examine the cerebral function remodeling mechanism. DESIGN, TIME AND SETTING： A randomized and controlled observation which was performed in Dongzhimen Hospital, Beijing University of Traditional Chinese Medicine from January to March, 2007. MATERIALS： Twenty-six healthy male Sprague Dawley rats were used to establish middle cerebral artery occlusion based on the Longa method. Sanqi tongshu capsules （containing 100 mg PTS per tablet） were provided by the Chengdu Huashen Group and nimodipine tablets （30 mg） by Tianjin Zhongyang Pharmaceutical Co., Ltd. METHODS： Twenty-six rats were randomly divided into an operation group （n = 21 ） and a control group （n = 5）. The operation group underwent the EZ Longa procedure to make the middle cerebral artery occlusion model. After surgery rats were randomly divided into a model group, a PTS group and a nimodipine group, with seven rats in each group. Rats were intragastrically administrated with saline （2 mL/d） in the model group, with Sanqi tongshu capsule （5.4 mg/100 g/d） in the PTS group, and with nimodipine （1.73 mg/100 g/d） in the nimodipine group. Rats in the control group did not undergo model establishment and drug administration. MAIN OUTCOME MEASURES： The expressions of Syp and PSD-95 were measured by immunohistochemical and image analysis at days 3, 7 and 28 after the operation. RESULTS： The expression of Syp and PSD-95 in the operation group was significantly lower than in the control group at days 3, 7     

Expression and effect of sodium-potassium-chloride cotransporter on dorsal root ganglion neurons in a rat model of chronic constriction injury

Sodium-potassium-chloride cotransporter 1 (NKCC1) and potassium-chloride cotransporter 2 (KCC2) are associated with the transmission of peripheral pain.We investigated whether the increase of NKCC1 and KCC2 is associated with peripheral pain transmission in dorsal root ganglion neurons.To this aim,rats with persistent hyperalgesia were randomly divided into four groups.Rats in the control group received no treatment,and the rat sciatic nerve was only exposed in the sham group.Rats in the chronic constriction injury group were established into chronic constriction injury models by ligating sciatic nerve and rats were given bumetanide,an inhibitor of NKCC1,based on chronic constriction injury modeling in the chronic constriction injury + bumetanide group.In the experiment measuring thermal withdrawal latency,bumetanide (15 mg/kg) was intravenously administered.In the patch clamp experiment,bumetanide (10 μg/μL) and acutely isolated dorsal root ganglion neurons (on day 14) were incubated for 1 hour,or bumetanide (5 μg/μL) was intrathecally injected.The Hargreaves test was conducted to detect changes in thermal hyperalgesia in rats.We found that the thermal withdrawal latency of rats was significantly decreased on days 7,14,and 21 after model establishment.After intravenous injection of bumetanide,the reduction in thermal retraction latency caused by model establishment was significantly inhibited.Immunohistochemistry and western blot assay results revealed that the immune response and protein expression of NKCC1 in dorsal root ganglion neurons of the chronic constriction injury group increased significantly on days 7,14,and 21 after model establishment.No immune response or protein expression of KCC2 was observed in dorsal root ganglion neurons before and after model establishment.The Cl^– (chloride ion) fluorescent probe technique was used to evaluate the change of Cl^– concentration in dorsal root ganglion neurons of chronic constriction injury model rats.We found that the relative optical density of N-(ethoxycarbonylmethyl)-6-methoxyquinolinium bromide (a Cl^– fluorescent probe whose fluorescence Cenintensity decreases as Cl– concentration increases) in the dorsal root ganglion neurons of the chronic constriction injury group was significantly decreased on days 7 and 14 after model establishment.The whole-cell patch clamp technique revealed that the resting potential and action potential frequency of dorsal root ganglion neurons increased,and the threshold and rheobase of action potentials decreased in the chronic constriction injury group on day 14 after model establishment.After bumetanide administration,the above indicators were significantly suppressed.These results confirm that CCI can induce abnormal overexpression of NKCC1,thereby increasing the Cl^– concentration in dorsal root ganglion neurons;this then enhances the excitability of dorsal root ganglion neurons and ultimately promotes hyperalgesia and allodynia.In addition,bumetanide can achieve analgesic effects.All experiments were approved by the Institutional Ethics Review Board at the First Affiliated Hospital,College of Medicine,Shihezi University,China on February 22,2017 (approval No.A2017-169-01).     

Changes in brain-derived neurotrophic factor expression after transplanting microencapsulated sciatic nerve cells of rabbits into injured spinal cord of rats

BACKGROUND: Changes of brain-derived neurotrophic factor (BDNF) expression reflect function of nerve cells; meanwhile, they play a significant role in researching interventions on plerosis of nerve injury. OBJECTIVE: To observe and compare the effects on changes of BDNF expression in rats with spinal cord injury between microencapsulated sciatic nerve cells of rabbits and only transplanting sciatic nerve cells of rabbits. DESIGN: Randomized controlled animal study. SETTING: Medical School of Jiujiang College. MATERIALS: The experiment was carried out in the Medical Science Researching Center, Jiujiang College from May 2004 to May 2006. A total of 90 healthy adult SD rats, weighing 250–300 g, of either gender; and 10 rabbits, weighing 2.0–2.5 kg, of either gender, were provided by Jiangxi Experimental Animal Center. METHODS: Sciatic nerve tissue of rabbits was separated to make cell suspension. After centrifugation, suspension was mixed with 15 g/L alginate saline solution and ejaculated to 20 mmol/L barium chloride saline solution by double-cavity ejaculator. The obtained cell microcapsules were suspended in saline. Rats were randomly divided into microencapsulated group, only suspension group, and only injured group with 30 animals in each group. After anesthesia, T10 spinous process and vertebra lamina of rats in the former two groups were exposed. Spinal cord tissue in 2-mm length was removed from rats by spinal cord right hemi-section. The gelatin sponges with the size of 2 mm × 2 mm × 2 mm were grafted as filing cage, and absorbed 10 μL microencapsulated sciatic nerve cells of rabbit in the microencapsulated group and 10 μL sciatic nerve cells of rabbits in the only suspension group; respectively. No graft was placed in the only injured group. MAIN OUTCOME MEASURES: On the 1st, 3rd, 7th, 14th and 28th days after operation, immunohistochemistry (SABC technique) was used to detect distribution and amount of positive-reactive neurons in BDNF of spinal cord samples which were selected as 2 cm away from the injured surface. RESULTS: All the 90 rats were involved in the final analysis. Masses of brown-yellow particles were found in the microencapsulated group, and most of them were distributed in the spinal cord anterior horn neurons and glial cells. The positive-reactive neuron particles were also found in the white matter and gray matter. On the 3rd, 7th, 14th and 28th days after operation, amount of positive-reactive neurons in BDNF in the microencapsulated group was higher than that in the only injured group (P < 0.01) and only suspension group (P < 0.05). CONCLUSION: After transplanting microencapsulated nerve cell suspension into injured spinal cord of rats, distribution and amount of positive-reactive neurons in BDNF of local samples at injured surface are increased remarkably as compared with those by using tissue cell transplantation.     

Facial nucleus up-regulation of brain-derived neurotrophic factor mRNA following electroacupuncture treatment in a rabbit model of facial nerve injury*★

BACKGROUND： The effect of acupuncture treatment on peripheral facial nerve injury is generally accepted. However, the mechanisms of action remain poorly understood. OBJECTIVE： To validate the effect of acupoint electro-stimulation on brain-derived neurotrophic factor （BDNF） mRNA expression in the facial nucleus of rabbits with facial nerve injury, with the hypothesis that acupuncture treatment efficacy is related to BDNE DESIGN, TIME AND SETTING： Peripheral facial nerve injury, in situ hybridization, and randomized, controlled, animal trial. The experiment was performed at the Laboratory of Anatomy, Heilongjiang University of Chinese Medicine from March to September 2005. MATERIALS： A total of 120 healthy, adult, Japanese rabbits, with an equal number of males and females were selected. Models of peripheral facial nerve injury were established using the facial nerve pressing method. METHODS： The rabbits were randomly divided into five groups （n = 24）： sham operation, an incision to the left facial skin, followed by suture; model, no treatment following facial nerve model establishment; western medicine, 10 mg vitamin B1, 50 ug vitamin B12, and dexamethasone （2 mg/d, reduced to half every 7 days） intramuscular injection starting with the first day following lesion, once per day; traditional acupuncture, acupuncture at Ytfeng, Quanliao, Dicang, Jiache, Sibai, and Yangbai acupoints using a acupuncture needle with needle twirling every 10 minutes, followed by needle retention for 30 minutes, for successive 5 days; electroacupuncture, similar to the traditional acupuncture group, the Yifeng （negative electrode）, Jiache （positive electrode）, Dicang （negative electrode）, and Sibai （positive electrode） points were connected to an universal pulse electro-therapeutic apparatus for 30 minutes per day, with disperse-dense waves for successive 5 days, and resting for 2 days. MAIN OUTCOME MEASURES： Left hemisphere brain stem tissues were harvested on post-operative days 7, 14, 21, and     

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 day 7 post injury (P<0.01). This did not decrease until day 14 post injury. Facial neuron apoptosis was detected on day 3 post injury and this was even more obvious on day 7 and was maintained to day 14 post injury. The number of cells expressing PSD-95 and displaying severe degrees of facial neuron apoptosis were as follows: cut group>clamp group>exposure group.CONCLUSION: The apoptotic extent of facial neurons and the expression of PSD-95 in apoptotic facial neurons increased with the degree of aggravation of injured severity of facial nerve.     

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 FMNs, 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 210-230g. 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 (5000U/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 analysis. FMN survival ratios, both in rhEPO treatment group and control group, decreased gradually between seven and 28 days; however, FMN survival ratios were significantly greater in the rhEPO treatment group compared to the control group (P<0.05). No TUNEL-positive cells were observed three days after injury in the rhEPO treatment and control groups; however, by seven days after injury, apoptotic cells were observed and peaked by 14 days in the control group. Between seven and 21 days, apoptotic cell numbers were significantly lower in the rhEPO treatment group compared to the control group (P<0.05). The expression of Caspase-3 increased three days after injury and peaked at 14 days in the control group. Nevertheless, Caspase-3 expression was significantly lower in the rhEPO treatment group compared to the control group at each time point (P<0.05).CONCLUSION: Treatment with rhEPO can effectively protect facial motoneurons by reducing expression of Caspase-3 and inhibiting apoptosis.     

Ginsenoside Rg1 changes brain-derived neurotrophic factor expression in the facial nucleus of rats after ovariectomy:A semiquantitative analysis

BACKGROUND: Estrogen is neuroprotective, but long-term estrogen treatment can induce side effects such as breast carcinoma, endometrial cancer, and stroke. However, phytoestrogen is neuroprotective without these side effects.OBJECTIVE: To study the effects of Ginsenoside Rg1 on facial neurons and brain-derived neurotrophic factor (BDNF) expression in the facial nucleus in ovariectomized rats.DESIGN, TIME AND SETTING: The randomized, controlled animal experiments were performed at the Ultrasonic Institute, Second Affiliated Hospital, Chongqing Medical University, China, from September 2007 to September 2008.MATERIALS: Ginsenoside Rg1 (Sigma, USA), rabbit anti-rat BDNF, Bcl-2, Bax antibodies, biotin-labeled goat anti-rabbit IgG (Boster, China), and a TUNEL kit (Roche, Germany) were used in this study.METHODS: A total of 48 adult Sprague Dawley rats undergoing ovariectomy were randomly assigned into sham operation (n=8), model (n=20), and Ginsenoside Rg1 (n=20) groups. Facial nerve damage was induced by bilateral clamping of the facial nerve trunk. The bilateral facial nerve trunk was exposed in the sham operation group, with no clamping. Rats in the Ginsenoside Rg1 group were intraperitoneally injected with 10 mg/kg per day Ginsenoside Rg1; other groups received 2 mL saline, once a day, for 14 days.MAIN OUTCOME MEASURES: Morphologic changes in neurons of the facial nucleus were observed following hematoxylin-eosin staining. Neuronal apoptosis was detected by TUNEL. Changes in ultrastructure of the facial nerve fibers were observed with a transmission electron microscope. Expression of BDNF, Bcl-2, and Bax protein was quantified by semiquantitative immunohistochemistry.RESULTS: At 3-14 days following facial nerve damage, Ginsenoside Rg1 increased BDNF expression and the number of regenerated nerve fibers, and produced thicker myelin sheaths (P< 0.05). Ginsenoside Rg1 also gradually increased Bcl-2 protein expression and decreased Bax protein expression (P < 0.05). By day 7, apoptosis was observed in facial neurons, but Ginsenoside Rg1 reduced the number of apoptotic neurons. Sham animals did not show any changes in BDNF, Bcl-2, or Bax expression or facial neuron morphology.CONCLUSION: Ginsenoside Rg1 can substantially inhibit facial neuronal apoptosis by increasing endogenous BDNF and Bcl-2 expression and by decreasing Bax expression in ovariectomized rats after facial nerve damage.     

Agmatine promotes expression of brain-derived neurotrophic factor in brainstem facial nucleus in the rat facial nerve injury model★

BACKGROUND: Studies have shown that agmatine can reduce inhibition of neuronal regeneration by increasing cyclic adenosine monophosphate and brain-derived neurotrophic factor (BDNF) in the hippocampus of morphine-dependent rats. The hypothesis that agmatine exerts similar effects on facial nerve injury deserves further analysis.OBJECTIVE: To study the effects of peritoneal agmatine injection on BDNF levels in the rat brainstem after facial nerve injury.DESIGN, TIME AND SETTING: A controlled animal experiment was performed at the Department of Otolaryngology-Head and Neck Surgery at the Second Affiliated Hospital, Chongqing University of Medical Sciences (Chongqing, China), between October and December in 2007.MATERIALS: Twenty-four male Sprague-Dawley rats were randomly divided into a control, a lesion, and an agmatine treatment group, with eight rats in each group. Bilateral facial nerve anastomosis was induced in the lesion and agmatine treatment groups, while the control group remained untreated. A rat BDNF Enzyme-linked immunosorbent assay kit was used to measure BDNF levels in the brainstem facial nucleus.METHODS: Starting on the day of lesion, the agmatine group received a peritoneal injection of 100 mg/kg agmatine, once per day, for a week, whereas rats in the lesion group received saline injections.MAIN OUTCOME MEASURES: BDNF levels in the brainstem containing facial nucleus were measured by ELISA.RESULTS: Twenty-four rats were included in the final analysis without any loss. Two weeks after lesion, BDNF levels were significantly higher in the lesion group than in the control group (P<0.01). A significant increase was noted in the agmatine group compared to the lesion group (P<0.01).CONCLUSION: Agmatine can substantially increase BDNF levels in the rat brainstem after facial nerve injury.     

Inhibition of lipid peroxidation attenuates axotomy-induced apoptotic degeneration of facial motor neurons in neonatal rats

The purpose of this study was to investigate the role of oxygen radical-induced lipid peroxidative mechanisms in trophic deprivation-induced apoptotic motor neuronal degeneration by testing the ability of the 21-aminosteroid lipid peroxidation inhibitor tirilazad mesylate (U-74006F) to attenuate the retrograde degeneration of facial motor neurons following axotomy in 14-day-old rat pups. On day 0, the right facial nerve of each rat was transected at its point of exit from the stylomastoid foramen. Pups were treated orally with either 10 or 30 mg/kg U-74006F or cyclodextrin vehicle 10 min before axotomy, and post-treated once a day from days 1 to 6, and then once every other day from days 8 to 21. The rats were sacrificed 3 weeks post-transection and the surviving motor neurons, identified through choline acetyl-transferase immunocytochemistry, were counted in three regions (planes) in the facial nucleus. In vehicle-treated rats, 56.2% (region A), 50.6% (region B), and 57.4% (region C) of the motor neurons in the ipsilateral facial nucleus survived 21 days following facial nerve axotomy in comparison to the non-axotomized contralateral nucleus (P < 0.0001). Treatment with 10 mg/kg U-74006F significantly enhanced motor neuron survival in regions B and C to 72.8% (P < 0.01) and 66.7% (P < 0.02%), respectively. The 30 mg/kg dose level also increased survival rates to 64.2% (P < 0.02) and 67.9% (P < 0.01), respectively. A second experiment demonstrated that oral dosing with U-74006F (30 mg/kg), when limited to the first 5 days after axotomy, also significantly blunted retrograde degeneration measured at 21 days post-axotomy. The efficacy of the lipid peroxidation inhibitor U-74006F in protecting a portion of the facial motor neuron pool from post-axotomy degeneration suggests that lipid peroxidation may play a mechanistic role in trophic deprivation-induced apoptotic neuronal death. © 1996 Wiley-Liss, Inc.     

Facial nucleus up-regulation of brain-derived neurotrophic factor mRNA following electroacupuncture treatment in a rabbit model of facial nerve injury

BACKGROUND:The effect of acupuncture treatment on peripheral facial nerve injury is generally ac-cepted. However,the mechanisms of action remain poorly understood. OBJECTIVE: To validate the effect of acupoint electro-stimulation on brain-derived neurotrophic factor (BDNF) mRNA expression in the facial nucleus of rabbits with facial nerve injury,with the hypothesis that acupuncture treatment efficacy is related to BDNF. DESIGN,TIME AND SETTING: Peripheral facial nerve injury,in situ hybridization,and random...     

Co-expression of calretinin and parvalbumin in the rat facial nucleus

BACKGROUND: Calretinin and parvalbumin are members of the intracellular calcium binding protein family, which transform Ca2 bioinformation into regulation of neuronal and neural network activities. OBJECTIVE: To observe expression and co-expression of calretinin and parvalbumin in rat facial nucleus neurons. DESIGN, TIME AND SETTING: Neuronal morphology experiment was performed at the Research Laboratory of Applied Anatomy, Department Neurobiology and Anatomy, Xiangya Medical College of Central South University from August to October 2007. MATERIALS: Five healthy, adult Sprague Dawley rats were selected. Polyclonal rabbit-anti-parvalbumin and mouse-anti-calretinin were provided by Sigma, USA. METHODS: Rat brains were obtained and cut into coronal slices using a freezing microtome. Slices from the experimental group were immunofluorescent stained with polyclonal rabbit-anti-parvalbumin and mouse-anti-calretinin antibodies. The control group sections were stained with normal rabbit and mouse sera. MAIN OUTCOME MEASURES: lmmunofluorescent double-staining was used to detect calretinin and parvalbumin expression. Nissi staining was utilized for facial nucleus localization and neuronal morphology analysis. RESULTS: The majority of facial motor neurons was polygon-shaped, and expressed calretinin and parvalbumin. The calretinin-immunopositive neurons also exhibited parvalbumin immunoreactivity, that is, calretinin and parvalbumin were co-expressed in the same neuron. CONCLUSION: Calretinin and parvalbumin were expressed in facial nucleus neurons, with varied distribution.     

坐骨神经非冻结性冷损伤后背根神经节细胞的凋亡

目的观察大鼠坐骨神经在非冻结性低温作用后,腰段脊髓L4-L6背根神经节(dorsal root ganglion,DRG)凋亡神经元的数量以及形态学改变,探讨周围神经非冻结性冷损伤致DRG神经元凋亡的情况。方法雄性Wistar大鼠33只,随机分为1周组、2周组、3周组,每组11只。每只大鼠取任意一侧坐骨神经为实验侧,给予冷损伤(4℃,2h),对照侧坐骨神经同样方法暴露,不给予低温处理。根据坐骨神经和DRG的病理变化,分别取两侧的L4、L5、L6背根神经节于低温结束后1周、2周、3周采用流式细胞仪(Annexin/PI法)和Tunel法对DRG神经元凋亡进行定量和定性检测。结果流式细胞仪(Annexin/PI法)定量测定结果显示,实验侧凋亡率明显高于对照侧。Tunel法检测发现受冷侧的DRG出现典型的Tunel染色阳性的早期凋亡细胞,半定量测定显示实验侧DRG神经元凋亡率明显高于对照侧。两种方法均显示受冷后1周开始凋亡细胞增多,2周时到达高峰,3周时略下降。结论非冻结性低温可以造成坐骨神经对应的L4、L5、L6DRG神经元出现凋亡,凋亡的高峰出现在冷损伤后2周,以早期凋亡为主。凋亡可能是坐骨神经冷损伤的机制之一。