早期激素干预对急性一氧化碳中毒大鼠迟发性脑病的预防作用

目的观察早期激素干预对急性一氧化碳中毒大鼠迟发性脑病（DEACMP）的预防作用。方法将132只雄性Wistar大鼠随机分成3个实验组：CO中毒组（COP组）、CO中毒＋地塞米松10 mg/kg组（DSMS-10组）和CO中毒＋地塞米松30 mg/kg组（DSMS-30组）,每组40只。另设健康对照组（NC组）,12只。实验组按150 ml/kg腹腔内注射CO制备急性一氧化碳中毒动物模型,健康对照组大鼠注射等体积的空气。在中毒后30 min内DSMS-10组腹腔内注射地塞米松剂量为10 mg/kg/d,共7 d;DSMS-30组腹腔内注射地塞米松剂量为30 mg/kg/d,共7 d;NC组和COP组则注射等剂量生理盐水。监测中毒后90 min、7 d、14 d、21 d各组大鼠血清中髓鞘碱性蛋白（MBP）的含量,并在上述各时间点处死大鼠取脑组织,行HE及MBP免疫组化染色。采用Morris水迷宫实验评估动物的智力状态。结果 Morris水迷宫实验结果显示,COP组中有8只大鼠被判定为迟发性脑病;DSMS-10组中有6只被判定为迟发性脑病;而DSMS-30组和对照组未出现迟发性脑病。COP组大鼠血清中MBP含量增高最显著,DSMS-10组也有增高,DSMS-30组接近正常。差异在中毒后90 min、7 d最明显。病理学检查显示COP组中发生迟发性脑病的大鼠在中毒90 min~21 d后脑海马、皮质下出现神经元损伤、髓鞘碱性蛋白脱失等病理改变,上述病理改变在各实验组中均可观察到,但以COP组大鼠病变程度最重,DSMS-30组最轻。结论10 mg/kg地塞米松可降低急性一氧化碳中毒大鼠迟发性脑病的发生率。30 mg/kg地塞米松则可避免迟发性脑病的发生。     

Erythropoietin reduces white matter damage in two-day-old rats exposed to hypoxic/ischemia injury

Objective: The aim of the study was to investigate whether erythropoietin (EPO) could protect against white matter damage (WMD) in a preterm equivalent neonatal rat hypoxic-ischemia (HI) model.

Methods: 113 two-day-old male rat pups were divided randomly into three groups: sham-treated, bilateral carotid artery occlusion (BCAO)-treated, BCAO + EPO-treated group. EPO (50 U/10 g body weight) or saline alone was administered intraperitoneally immediately after BCAO surgery. Body weight, brain weight, brain water content, and expression of myelin basic protein (MBP) were assessed at day 1, 3, 7, and 14 after HI insult. Morris water-maze (MWM) test was used to assess neurological behavior from day 31 to 35 after HI insult.

Results: Body weights of BCAO + EPO group were greater than those of BCAO group rats (P < 0.05). Specifically, at day 3 and 7 after HI, brain weights of BCAO + EPO-treated rats were higher than BCAO-treated animals (P < 0.05); at day 7 and 14 after HI, MBP of BCAO + EPO-treated rats were higher than BCAO-treated animals (P < 0.05). Similarly, the brain water content at day 3 after HI in BCAO + EPO-treated rats was lower than BCAO-treated animals (P < 0.05). The body weight, brain weight, brain water content, and MBP expression in BCAO + EPO-treated group were comparable to those in the sham-treated group. Spatial learning and memory of BCAO + EPO-treated rats was significantly improved over the BCAO-treated group and was comparable to the sham-operated animals.

Conclusion: EPO treatment could be a potential intervention in treating WMD for preterm infants.     

Brain slice viability determined under normoxic and oxidative stress conditions: involvement of slice quantity in the medium

ABSTRACT

Objective: In vitro acute adult brain slice methods are instruments in developing our knowledge of the nervous system. Optimization of this method for obtaining high-quality brain slices is extremely important in terms of consistency and reliability of the experimental results. Although some important topics such as slice thickness, temperature, and composition of the physiological medium have been studied for optimization, involvement of slice quantity in medium on tissue viability has not been investigated yet.

Methods: Different number of slices (1, 3, or 6 slices) were incubated under normoxic or some prooxidant stress conditions induced by oxygen–glucose deprivation (OGD), H₂O₂, FeSO₄+ ascorbic acid, or menadione to evaluate the effect of slice density on tissue viability.

Results:Slice quantity in the normoxic incubation medium caused a significant increase in 2,3,5-triphenyltetrazolium chloride (TTC) staining intensity of the slices. Similarly, increase in the slice quantity in the medium also protected the slices against either OGD, H₂O₂, FeSO_4, or menadione-induced decrease in TTC staining. In addition to TTC staining, lactate dehydrogenase leakage or malondialdehyde and reactive oxygen species production under normoxic or ischemia-like conditions were also attenuated by increasing slice quantity in the medium.

Conclusion: These results show that when using brain slices method for investigating the structural and functional features of brain at the molecular and cellular levels, both slice quantity in the medium and incubation volume should be considered first. Increasing slice quantity or decreasing incubation volume probably causes an increase in the concentration of endogenous substance(s) involved in neuroprotection.     

Simvastatin attenuates hypomyelination induced by hypoxia–ischemia in neonatal rats

Abstract

Objectives: Simvastatin, the most widely used cholesterol-lowering drug, has been reported to protect the adult brain from ischemia. Nevertheless, little is known about its action on developing brain after stroke. Although a few reports have found recently that simvastatin displays anti-inflammation and anti-apoptosis properties and improves the cognitive and morphological consequences in the neonatal rats after hypoxia–ischemia (HI) damage, to our best knowledge, there has been no study of the effect of it on myelin formation after neonatal brain damage. Therefore, we investigated whether simvastatin could promote the myelination of oligodendrocytes in the neonatal rats after HI and explored the possible role of microglial responses in this process.

Methods: Postnatal day 7 Sprague–Dawley rats were subjected to HI. White matter integrity and myelination were evaluated by the densitometry of myelin basic protein (MBP) immunostaining. OX-42 immunoreactivity and nissl staining were used for identifying microglial responses and the structure changes of white matter and adjacent gray matter after HI. Simvastatin was administrated prophylactically to rats.

Results: HI induced serious hypomyelination especially in external and internal capsules 3 and 7 days after HI, accompanying with microglial activation remarkably. Simvastatin treatment greatly increased the densities of MBP immunostaining, inhibited microglial activation and reduced the numbers of pyknotic cells and neuronal loss.

Discussion: The present study shows that simvastatin treatment in neonatal rats attenuates HI-induced developing oligodendrocytes injury and hypomyelination. Its anti-inflammatory properties via suppression of microglial activation are likely to contribute to this action. It provides experimental evidence to support the neuroprotective effects of statins in neonatal ischemic stroke.     

Urinary trypsin inhibitor suppresses excessive superoxide anion radical generation in blood,oxidative stress,early inflammation,and endothelial injury in forebrain ischemia/reperfusion rats

Abstract

Objectives: To investigate the effects of ulinastatin, a urinary trypsin inhibitor (UTI), on jugular venous superoxide radical (O^?₂·) generation, oxidative stress, early inflammation, and endothelial activation in forebrain ischemia/reperfusion (FBI/R) rats.Methods: Fourteen Wistar rats were allocated to a control group (n = 7) and a UTI group (n = 7). Throughout the experiments, O^?₂· in the jugular vein was measured by the produced current using a novel electrochemical O^?₂· sensor. Forebrain ischemia was induced by occlusion of the bilateral common caroti darteries with hemorrhagic hypotension for 20 min, followed by reperfusion. In the UTI group, UTI (5 U/g) was administered intravenously immediately after reperfusion. At 60 min after reperfusion, plasma and brain were harvested, and malondialdehyde, high-mobility group box 1 (HMGB1) protein, and intercellular adhesion molecule-1 (ICAM-1) were measured.

Results: O^?₂· current increased gradually during forebrain ischemia in both groups. The current increased markedly in the control group immediately after reperfusion but was significantly attenuated in the UTI group after reperfusion. Brain and plasma malondialdehyde, HMGB1, and ICAM-1 were significantly attenuated in the UTI group compared with those in the control group, except for brain HMGB1, which was associated with the amount of O^?₂· generated during FBI/R.

Discussion: UTI suppressed jugular venous O^?₂· generation, oxidative stress, early inflammation, and endothelial activation in FBI/R rats. Therefore, UTI might be a useful agent for the therapy of the cerebral ischemia/reperfusion pathophysiology.     

Nuclear factor‐κB/Bcl‐XL pathway is involved in the protective effect of hydrogen‐rich saline on the brain following experimental subarachnoid hemorrhage in rabbits

Early brain injury (EBI), a significant contributor to poor outcome after subarachnoid hemorrhage (SAH), is intimately associated with neuronal apoptosis. Recently, the protective role of hydrogen (H₂) in the brain has been widely studied, but the underlying mechanism remains elusive. Numerous studies have shown nuclear factor‐κB (NF‐κB) as a crucial survival pathway in neurons. Here we investigated the role of H₂ in EBI following SAH, focusing on the NF‐κB pathway. A double blood injection model was used to produce experimental SAH, and H₂‐rich saline was injected intraperitoneally. NF‐κB activity within the occipital cortex was measured. Immunofluorescence was performed to demonstrate the activation of NF‐κB; Bcl‐xL and cleaved caspase‐3 were determined via Western blot. Gene expression of Bcl‐xL was detected by real‐time PCR, and TUNEL and Nissl staining were performed to illustrate brain injury in the occipital cortex. SAH induced a significant increase of cleaved caspase‐3. Correspondingly, TUNEL staining demonstrated obvious neuronal apoptosis following SAH. In contrast, H₂ treatment markedly increased NF‐κB activity and the expression of Bcl‐xL and decreased the level of cleaved caspase‐3. Additionally, H₂ treatment significantly reduced post‐SAH neuronal apoptosis. The current study shows that H₂ treatment alleviates EBI in the rabbits following SAH and that NF‐κB/Bcl‐xL pathway is involved in the protective role of H₂. © 2013 Wiley Periodicals, Inc.     

Normobaric hyperoxia retards the evolution of ischemic brain tissue toward infarction in a rat model of transient focal cerebral ischemia

Objectives: Oxygen therapy has been long considered a logical therapy for ischemic stroke. Our previous studies showed that normobaric hyperoxia (normobaric hyperoxia (NBO), 95% O₂ with 5% CO₂) treatment during ischemia reduced ischemic neuronal death and cerebromicrovascular injury in animal stroke models. In this study, we studied the effects of NBO on the evolution of ischemic brain tissue to infarction in a rat model of transient focal cerebral ischemia.

Methods: Male Sprague-Dawley rats were given NBO (95% O₂) or normoxia (21% O₂) during 90-min filament occlusion of the middle cerebral artery (MCAO), followed by 3 or 22.5 h of reperfusion. 2,3,5-triphenyltetrazolium chloride (TTC) staining was used to evaluate the longitudinal evolution of tissue infarction.

Results： In normoxic rats, MCA-supplied cortical and striatal tissue was infarcted after 90-min MCAO with 22.5 h of reperfusion. NBO-treated rats showed a 61.4% reduction in infarct size and tissue infarction mainly occurred in the ischemic striatum. When infarction was assessed at an earlier time point, i.e. at 3 h of reperfusion, normoxic rats showed significantly smaller but mature infarction (no TTC staining, white color), with the infarction mainly occurring in the striatum. Unexpectedly, NBO-treated rats only showed immature lesion (partially stained by TTC, light white color) in the ischemic striatum, indicating that NBO treatment also retarded the process of neuronal death in the ischemic core. Of note, NBO-preserved striatal tissue underwent infarction after prolonged reperfusion.

Conclusions： Our results demonstrate that NBO treatment given during cerebral ischemia retards the evolution of ischemic brain tissue toward infarction and NBO-preserved cortical tissue survives better than NBO-preserved striatal tissue during the phase of reperfusion.     

白藜芦醇对脑创伤后小胶质细胞激活的影响

目的检测白藜芦醇治疗后大鼠脑损伤区激活小胶质细胞的形态及数量改变,以探讨白藜芦醇的脑保护机制。方法健康雄性SD大鼠75只,随机分为创伤组、对照组和治疗组,每组分伤后3、12、24、48和72h共5个时间点,各时间点每组5只动物,用改良Feeney自由落体法致伤动物。治疗组予以白藜芦醇(50mg/kg体重)腹腔注射,对照组给予等量生理盐水,创伤组未给予药物处理。分别于伤后各时间点麻醉动物,取伤区脑组织,用抗OX-42免疫组化法检测小胶质细胞变化。结果伤后早期小胶质细胞即被激活,在不同时间点小胶质细胞形态不同:正常大鼠脑内小胶质细胞处于静息状态,细胞形态不清晰;伤后3h,OX-42浅染,小胶质细胞形态可见;伤后12h,小胶质细胞反应明显,OX-42深染,细胞形态清楚;伤后24h,小胶质细胞反应达高峰,细胞形态清晰,突起上可见到小棘;48h以后,反应减弱,OX-42浅染,细胞数量减少。治疗组小胶质细胞数量明显减少(P<0.05),创伤组与对照组无明显差异(P>0.05)。结论伤后不同时间点激活小胶质细胞的形态和数目不同,白藜芦醇能抑制小胶质细胞的激活,具有脑保护作用。     

髓鞘碱性蛋白对急性一氧化碳中毒大鼠最终结局的预测价值及地塞米松干预的作用

目的评估髓鞘碱性蛋白(MBP)对急性一氧化碳(CO)中毒大鼠最终结局的预测价值,并探讨不同剂量地塞米松对急性CO中毒大鼠最终结局的干预作用。方法将130只体质量180²80g、雄性Wistar大鼠随机分成3个实验组(每组n=40)和健康对照组(n=10),即CO中毒组(CO中毒组);CO中毒+10mg·Kg-1·d-1地塞米松组(DXM-10组);CO中毒+30mg·Kg-1·d-1地塞米松组(DXM-30组)和健康对照组(NC组)。观察各组大鼠在染毒后21d内的死亡例数,并在染毒后60min断尾取血检测各组大鼠血清中MBP值。结果中毒后所有大鼠呈现典型急性CO中毒表现。在观察的21d内,CO中毒组中共有15只大鼠死亡,DXM-10组11只,而DXM-30组4只,死亡率分别为37.50%、27.50%和10.00%。而NC组中无大鼠死亡。实验组中所有死亡大鼠与存活大鼠其平均MBP值相比差异有统计学意义(P<0.05)。结论 CO中毒后60min腹腔内注射10mg·Kg-1·d-1地塞米松可降低急性CO中毒大鼠的死亡率,30mg·Kg-1·d-1地塞米松可显著降低其死亡率。MBP对急性CO中毒大鼠的最终结局具有预测价值。     

急性一氧化碳中毒大鼠脑红蛋白表达变化的研究

目的:研究急性一氧化碳中毒大鼠迟发性脑病模型中脑红蛋白(NGB)在额叶皮质和海马区的表达变化情况。方法:腹腔注射纯CO制备急性一氧化碳中毒与一氧化碳中毒迟发性脑病的大鼠模型。检测大鼠大脑皮质及海马区细胞的脑红蛋白的表达情况。结果:急性一氧化碳中毒后大鼠额叶皮质的NGB蛋白表达于损伤后第1天上调,以后逐渐降低至染毒后21d;而海马区NGB表达降低并呈持续减少的趋势,至染毒后21d最低;与对照组相比差异均有统计学意义(p<0.01)。病理学检测显示海马区神经细胞损伤程度较额叶皮质严重。结论:(1)脑不同部位对一氧化碳中毒的耐受性差异可能与NGB的表达有关。(2)NGB的表达下调可能与一氧化碳中毒迟发性脑病的发生与发展有关。     

Juvenile hyperactivity in rats after acute exposure to carbon monoxide

The hypothesis was tested that exposure of neonatal rats to carbon monoxide (CO) to the point of respiratory failure would result in brain damage evidenced as hyperactivity. Five-day-old rats were exposed in a dynamic flow chamber to a concentration of carbon monoxide in air which caused coma and respiratory failure (defined as failure to breathe in 20 sec) after about 2 hr of exposure. From 7 to 15 days after birth, signs of hyperactivity were present in the CO-exposed rats in an open field test. In the same age period, tests of reflex development did not demonstrate differences between CO-exposed and control rats. From 17 to 22 days of age, the CO-exposed rats were more often awake in the nest box than control rats. After weaning, the CO-exposed rats were found to be hyperactive, particularly at night, in a residential maze. This hyperactivity was present at 4, 5, 6, and 8 weeks of age, but the rats recovered by 3 months of age. When adult rats were exposed to CO, mild nocturnal hyperactivity usually developed several weeks after exposure, and no recovery was found up to 5 months later. The rapid onset and complete reversibility of hyperactivity in rats exposed to CO as neonates makes this form of anoxic damage an interesting model for further investigation.     

Preoperative Regimens of Magnesium Facilitate Recovery of Function and Prevent Subcortical Atrophy Following Lesions of the Rat Sensorimotor Cortex

Following brain injury, there is a reduction of intra- and extracellular levels of magnesium (Mg⁺⁺), which may contribute to the severity of the lesion-induced behavioral impairments. Injections of magnesium prior to or after brain injury attenuate these behavioral impairments. The present study extends these findings by manipulating the number of injections and the time period between the injections and the time of injury. Rats were given either two or five daily preoperative injections of MgCl₂ (1 mmol/kg, ip), or saline (1 ml/kg, ip) with the final injection given 24 h prior to electrolytic lesions of the somatic sensorimotor cortex (SMC). Following SMC lesions the rats exhibited contralateral deficits in forelimb placing and locomotor placing. Rats treated with either two or five preoperative injections of MgCl₂ showed a reduction in the initial magnitude of the contralateral deficits and an accelerated rate of recovery compared to saline-treated rats. In addition, analysis of striatal atrophy revealed that MgCl₂ treatment prevented atrophy in the ipsilateral posterior striatum compared to rats treated with saline. These data suggest that preoperative injections of MgCl₂ produce facilitation of sensorimotor recovery and reduce subcortical atrophy. Moreover, to observe the beneficial effects of MgCl₂, the timing of injections need not be tied to the period immediately around the brain injury. The present data may indicate that daily supplements of magnesium may partially protect against some of the deleterious effects of brain injury.     

ERK1/2 activation in reactive astrocytes of mice with pilocarpine-induced status epilepticus

Abstract

Objective: To investigate the activation pattern of extracellular signal-regulated kinase 1/2 (ERK1/2) in the hippocampus of mice during pilocarpine-induced status epilepticus (SE) and its relationship with reactive astrogliosis.

Methods: Status epilepticus (SE) models were established by intraperitoneal injection of pilocarpine. The intervention group received the ERK1/2 signaling pathway inhibitor SL327 before the pilocarpine injection. We evaluated the SE model group, the intervention group and the control saline-treated group, at 6 hours and 3 days after initiation of the seizure. Phosphorylated activated ERK1/2 and glial fibrillary acidic protein (GFAP) were labeled with both single-labeling and sequential single-labeling immunohistochemical techniques.

Results: Among the pilocarpine-treated (SE model) mice, strong immunohistochemical staining of phospho-ERK1/2 was observed in the neurons and astrocytes of the hippocampus at 6 hours after initiation of SE, whereas staining on the third day of SE was not different from the control saline-treated mice. In the SL327-treated mice (intervention group), SL327 effectively blocked the ERK1/2 activation and little gliosis could be detected at 6 hours and 3 days after initiation of SE; the levels of phospho-ERK1/2 remained low, but the level of gliosis was similar to that of SE mice.

Conclusion: The ERK1/2 signaling pathway plays an important role in the early stage of reactive astrogliosis in mice with pilocarpine-induced SE.     

Pretreatment of MQA,a caffeoylquinic acid derivative compound,protects against H2O2-induced oxidative stress in SH-SY5Y cells

Objectives: Compound MQA (1,5-O-dicaffeoyl-3-O-[4-malic acid methyl ester]-quinic acid) is a natural caffeoylquinic acid derivative isolated from Arctium lappa L. roots. This study aims to explore the neuroprotective effects of MQA against hydrogen peroxide (H₂O₂)-induced oxidative stress in SH-SY5Y neuroblastoma cells.

Methods: The SH-SY5Y cells were divided into four groups, including control, 20 μM MQA, 200 μM H2O2, 200 μM H2O2 + 20 μM MQA groups. The effects of MQA on H₂O₂-induced cell death were measured by MTT and LDH assays. Hoechst 33342 and Annexin V-PI double staining were used to observed H2O2-induced apoptosis. Also, the effects of MQA on antioxidant system and mitochondrial pathway were explored. Further, steady-state phosphorylation levels of ERK1/2, Akt and GSK-3β were examined by Western blot analysis.

Results: Pretreatment with MQA prevented cell death in SH-SY5Y cells exposed to 200 μM H2O2 for 3 h. Meanwhile, Hoechst 33342 and Annexin V-PI double staining showed that MQA attenuated H₂O₂-induced apoptosis. These changes are related to elevation in SOD activity, reduction in MDA production and ROS formation, and increases in mitochondrial membrane potential (MMP). In addition, the potential mechanisms of MQA against H₂O₂-induced apoptosis are associated with increases in the Bcl-2/Bax ratio, decreases in cytochrome c release, caspase-3 and caspase-9 expressions, phosphorylation of ERK1/2, and dephosphorylation of AKT and GSK-3β.

Conclusion: These findings suggest that protective effects of MQA against H₂O₂-induced apoptosis might be associated with mitochondrial apoptosis, ERK1/2 and AKT/GSK-3β pathway.     

Enchanced cytokines delivery and intercellular adhesion molecule 1 (lCAM-1) expression in glioma by intracarotid infusion of bradykinin analog,RMP-7

Abstract

The effect of intracarotid infusion of the bradykinin analog, RMP-7, on blood-to-tumor and blood-to-brain transport of three cytokines were investigated. Wistar rats with RG2 gliomas were utilized and a unidirectional transfer constant, Ki, was determined using quantitative autoradiography. Interferon-y (lFN-y), tumor necrosis factor-α (TNF-α), and interleukin-2 (lL-2J were labeled with 12510dine for quantitative transport studies using autoradiography. Radiolabeled cytokines were injected as an intravenous bolus. Intracarotid infusion of RMP-7 (0.7 J1g kg-min-¹) Jincreased the selective transport to tumors of IFN-y by 3.97-fold (p < 0.005), of TNF-α by 5.30-fold (p < 0.005), and of IL-2 by 4.34-fold (p < 0.005), compared to intracarotid saline infusion. To determine whether the increased IFN-y or TNF-α transport to tumors with RMP-7 could enhance expression of intercellular adhesion molecule 7 (lCAM-7 Jin tumors, ICAM-7 expression in RG2 glioma was evaluated by immunohistochemistry. Both IFN-α and TNF-α increased ICAM-l expression of RG2 cells in vitro. In vivo, intracarotid infusion of IFN-y combined with RMP-7 significantly enhanced ICAM-l expression in intracerebral RG2 gliomas compared to infusion of IFN-y without RMP-7. Expression of ICAM-1 was not enhanced by TNF-α combined with RMP-7. Intracarotid infusion of RMP-7 is a novel method of cytokines delivery to brain tumors. [Neural Res 1997; 19: 501-508]     

Effects of maternal exposure to LPS on the inflammatory response in the offspring

To investigate the effects of maternal infection on the offspring's inflammatory response, pups born to LPS- or saline-treated dams were stimulated with LPS or saline, and the expression of cytokines and chemokines was examined. We found that at P21, pups born to LPS-treated dams exhibited diminished serum levels of TNF-alpha, IL-1beta, and IL-6, and inhibited mRNA levels of cytokines, including TNF-alpha, IL-1beta, and IL-6, and chemokines, including MIP-1beta, MIP-2, and KC, in the brain, as compared to pups born to saline-treated dams at 2 h following LPS stimulation. Our results suggest that maternal infection suppresses the offspring's inflammatory response to LPS.     

大鼠脑创伤后小胶质细胞激活的时程及形态变化研究

目的探讨大鼠脑创伤后小胶质细胞激活的时程及形态变化。方法采用改良的Feeney等人的方法造成大鼠颅脑损伤模型,21只SD大鼠随机分为对照组和创伤组,后者根据伤后处死时间点不同,再分为伤后1h,6h,12h,24h,48h和72h组,每组动物3只,在伤后不同时间点处死动物,取伤区脑组织行抗OX-42免疫组织化学染色。结果正常大鼠脑内小胶质细胞一般为静息状态,OX-42为阴性,在切片上不易发现或细胞形态不清晰;伤后1h,小胶质细胞为轻度反应,OX-42浅染,细胞形态隐约可见,不规则;伤后6h,小胶质细胞反应明显,由静息状态变为早期反应状态,OX-42深染,细胞形态清楚;伤后12h,小胶质细胞反应达高峰,细胞形态更清楚,突起上可见到小棘;24h以后,反应减弱,OX-42浅染,细胞数量减少。结论大鼠脑创伤后小胶质细胞被激活,细胞形态发生改变,海马区亦有激活改变;反应的时程变化是伤后1h出现激活,6h反应明显,12h达高峰,以后逐渐减弱。     

hucMSCs transplantation promotes locomotor function recovery,reduces apoptosis and inhibits demyelination after SCI in rats

AimsSpinal cord injury (SCI) can cause a variety of cells apoptosis, neurodegeneration, and eventually permanent paralysis. This study aimed to examine whether transplanting human umbilical cord mesenchymal stem cells (hucMSCs) can promote locomotor function recovery, reduce apoptosis and inhibit demyelination in SCI models.Main methodsRats were allocated into Sham group (spinal cord exposure only), SCI + PBS group (spinal cord impact plus phosphate-buffered saline (PBS) injections), SCI + hucMSCs group (spinal cord impact plus hucMSCs injections) groups. Behavioral tests, Basso-Beattie-Bresnahan locomotion scores (BBB scores), were carried out at 0, 3, 7, 14, 21, 28 days after SCI surgery. Hematoxylin-eosin staining observed spinal cord morphology. Nissl staining detected the number of nissl bodies. Myelin basic protein (MBP) and oligodendrocyte (CNPase) were examed by immunohistochemical staining. The apoptosis of oligodendrocyte and neurons were detected by immunofluorescence.ResultsThe 28-day behavioral test showed that the BBB score of rats in the SCI + hucMSCs group increased significantly, comparing to the SCI + PBS group. The numbers of nissl bodies and myelin sheath in the damaged area of SCI + hucMSCs group were also significantly increased compared to the SCI + PBS group. HucMSCs transplanting decreased the expression of protein level of Caspase-3 and Bax and increased the Bcl-2, MBP and CNPase, rescued the apoptosis of neurons and the oligodendrocyte.ConclusionThese results showed that hucMSCs can improve motor function, tissue repairing and reducing apoptosis in SCI rats.     

Thioperamide, an H3 Receptor Antagonist Prevents [3H]Glucose Uptake in Brain of Adult Rats Lesioned as Neonates with 5,7-Dihydroxytryptamine

As a first attempt at exploring an association between histaminergic and serotoninergic neuronal phenotypes in glucose regulation, the influence of the histamine H₃ receptor antagonist thioperamide on glucose uptake by brain was determined in rats in which the serotoninergic innervations of brain was largely destroyed perinatally. Male Wistar rats were initially treated on the 3rd day after birth with the serotoninergic neurotoxin 5,7-dihydroxytryptamine (5,7-DHT) (75 μg icv) or saline vehicle (10 μl icv). At 8 weeks lesioned and control rats were terminated in order to validate the effectiveness of 5,7-DHT: reduction in 5-HT and 5-HIAA by 83–91% and 69–83% in striatum, frontal cortex, and hippocampus (HPLC/ED method). Other groups of rats were pretreated with thioperamide (5.0 mg/kg ip) or saline vehicle 60 min prior to 6-[³H]-D-glucose (500 μCi/kg ip). Fifteen-min later rats were decapitated and brains were excised and dissected to remove frontal cortex, striatum, hippocampus, thalamus/hypothalamus, pons, and cerebellum. Liquid scintillation spectroscopy was used to determine that [³H]glucose uptake, which was enhanced in 5,7-DHT lesioned rats in cortex (by 88%), hippocampus, thalamus/hypothalamus, pons and cerebellum (each by 47–56%), and in striatum (by 35%). In contrast, thioperamide prevented the enhancement in [³H]glucose uptake in all brain regions of 5,7-DHT neonatally lesioned rats; and [³H]glucose levels were significantly different in all brain regions (except thalamus/hypothalamus) in thioperamide-versus saline-treated rats. These findings indicate a functional association between histaminergic and serotoninergic systems in brain in relation to glucose regulation.     

Intranasal delivery of obidoxime to the brain prevents mortality and CNS damage from organophosphate poisoning

Intranasal delivery is an emerging method for bypassing the blood brain barrier (BBB) and targeting therapeutics to the CNS. Oximes are used to counteract the effects of organophosphate poisoning, but they do not readily cross the BBB. Therefore, they cannot effectively counteract the central neuropathologies caused by cholinergic over-activation when administered peripherally. For these reasons we examined intranasal administration of oximes in an animal model of severe organophosphate poisoning to determine their effectiveness in reducing mortality and seizure-induced neuronal degeneration. Using the paraoxon model of organophosphate poisoning, we administered the standard treatment (intramuscular pralidoxime plus atropine sulphate) to all animals and then compared the effectiveness of intranasal application of obidoxime (OBD) to saline in the control groups. Intranasally administered OBD was effective in partially reducing paraoxon-induced acetylcholinesterase inhibition in the brain and substantially reduced seizure severity and duration. Further, intranasal OBD completely prevented mortality, which was 41% in the animals given standard treatment plus intranasal saline. Fluoro-Jade-B staining revealed extensive neuronal degeneration in the surviving saline-treated animals 24 h after paraoxon administration, whereas no detectable degenerating neurons were observed in any of the animals given intranasal OBD 30 min before or 5 min after paraoxon administration. These findings demonstrate that intranasally administered oximes bypass the BBB more effectively than those administered peripherally and provide an effective method for protecting the brain from organophosphates. The addition of intranasally administered oximes to the current treatment regimen for organophosphate poisoning would improve efficacy, reducing both brain damage and mortality.