摘要
目的探讨电刺激大鼠小脑顶核(FNS)的神经保护作用与其调节诱生型环氧化酶(COX-2)表达的关系,并阐明FNS对COX-2表达的调节机制。方法将Wistar大鼠随机分为4组,即缺血再灌注组(I/R)、电刺激FNS组(I/R+FNS)、毁损FNS组(I/R+FNL)和假手术对照组。I/R+FNL组大鼠用鹅膏氨酸毁损两侧FNS,I/R+FNS组和I/R+FNL组大鼠均以电刺激器刺激左侧FNS。前三组大鼠用线栓法成功制作可复血流的大脑中动脉阻塞模型,2h后再灌注。在再灌注6、12、24、48h后将大鼠断头取脑。将上述各组、各时间点的动物均分为两部分,一部分以视交叉为中心切成2个2mm厚的脑片进行COX-2免疫组化染色和HE染色,同时检测再灌注24h各组血清神经元特异性烯醇化酶(NSE)水平；另一部分以视交叉为中心切成6 mm厚的脑片,以胼胝体为腹侧界限取病变侧皮层提取RNA,RNA样品通过逆转录—聚合酶链式反应的方法检测COX-2mRNA的表达。结果I/R+FNS组再灌注各时间点的COX-2免疫反应性均较相应I/R及I/R+FNL组各时间点的免疫反应性减低(P＜0．05),而I/R+FNL组与I/R组的COX-2的免疫反应无显著性差异(P＞0．05)。I/R+FNS组NSE水平较I/R及I/R+FNL低(P＜0．01)。I/R+FNS组再灌注各时间点的COX-2mRNA比I/R组及I/R+FNL组各相应时间点的COX-2mRNA均有不同程度的减低(P＜0．05),而I/R+FNL组与I/R组各相应时间点的COX-2mRNA无显著性差异(P＞0．05)。结论电刺激FNS可抑制COX-2 mRNA和COX-2过度表达,降低NSE水平。FNS毁损后。FNS对COX-2的抑制作用消失,说明电刺激FNS对COX-2的抑制是通过FNS实现的。电刺激FNS对COX-2的抑制是中枢神经源性神经保护机制之一。
Objective To elucidate the neuroprotective effects of electric stimulation in cerebella fastigial nucleus（FN） and its mechanism in regulating the expression of cyclooxygenase-2. Methods Male Wistar rats weighting 250±30 g were divided into 4 groups： ischemia reperfusion group,fastigial nucleus stimulation group, fastigial nucleus-lesion group, sham-operated group. The third group was destroyed by ibotemic acid 5 days before FN stimulation. The focal cerebral ischemia reperfusion model was made by thread embolish of middle cerebral artery in all groups except the fourth group. Rats were killed at 6, 12, 24 and 48 hours after ischemia reperfusion injury. The brain was removed, and half of the brain was sliced into two 2-mm coronal sections at the lever of the optic chiasm in order to detect the expression of cyclooxygenase-2 by immunocytochemistry and to observe the pathological injury of neurons by HE staining. The level of NSE of the serum in different groups at 24 h after reperfusion was assayed at the same time. The other half of the brain was removed and sliced into 6-mm coronal sections at the lever of the optic chiasm, and the infracted cortex was dissected using the corpus caUosum as a ventral landmark in order to detect the expression of COX-2 mRNA using RT-PCR. Results The expression of COX-2 in every time point in FN stimulation group was significantly reduced compared with that in ischemia reperfusion group and FN-lesion group, whereas no significant difference was observed between ischemia reperfusion and F.N-lcsion groups. The levels of NSE in FNS group were lower than those in ischemia reperfusion group and FN-lesi0n group at 24 h after reperfusion. Compared with FN stimulation group in every time point, the expression of COX-2 PCR product was significantly upregulated in ischemia reperfusion group and FN-lesion group, whereas no significant difference was observed between ischemia reperfusion and FN-lesion groups. Conclusion FNS could inhibit the expression of COX-2-immunoreactivity and COX-2 mRNA after ischemia reperfusion. FNS could also reduce the level of NSE after ischemia reperfusion injury. One of the neuroprotective mechanisms of electric stimulation in fastigial nucleus is associated with inhibition of the expres- sion of COX-2-immunoreactivity and COX-2 mRNA.
出处
《兰州大学学报（医学版）》
CAS
2006年第4期1-5,共5页
Journal of Lanzhou University（Medical Sciences）
基金
甘肃省自然科学基金(3ZS041-A25-062)资助项目。
关键词
脑缺血
诱生型环氧化酶
电刺激
小脑顶核
ischemia reperfusion
cyclooxygenase-2
electric stimulation
fastigial nucleus
