BQ-123通过mTOR-自噬通路对蛛网膜下腔出血大鼠神经细胞凋亡的影响*
Effect of BQ-123 on nerve cell apoptosis after subarachnoid hemorrhage in rats by mTOR-autophagy pathway

目的:探讨BQ-123对蛛网膜下腔出血(SAH)的治疗作用及其机制。方法:120只雄性SD大鼠,分为假手术(Sham)组、SAH组、雷帕霉素组、BQ-123干预组。二次注血法制作SAH大鼠模型; 镜下观察海马区组织形态结构变化; 免疫组化法和RT-PCR法检测海马区雷帕霉素靶蛋白(mTOR)、自噬相关基因Beclin-1 和微管相关蛋白1轻链(LC3)-Ⅱ的表达; TUNEL法检测细胞凋亡情况。结果:SAH组海马区可见神经细胞变性水肿和死亡; 血管内皮细胞肿胀、凝集,管腔受压、狭窄明显,管壁迂曲不平、缝隙连接断裂、基膜松散、模糊甚至分离。雷帕霉素组大部分细胞排列整齐、细胞结构完整; 血管内皮细胞肿胀、凝集,管腔受压、狭窄程度减轻,管壁迂曲不平; BQ-123干预组结构完整神经细胞显著增多; 血管内皮细胞凝集已少见,膜结构完整、清晰,基膜厚薄均匀。与SAH组比较,雷帕霉素组和BQ-123干预组海马区mTOR表达降低,Beclin-1和LC3-Ⅱ表达增加,凋亡神经细胞数量减少(P＜0.05)。结论:BQ-123可抑制SAH大鼠神经细胞凋亡,其机制与调控mTOR-自噬信号途径有关。
Aim: To investigate the therapeutical effect of BQ-123 on subarachnoid hemorrhage(SAH)in rats,and explore the mechanisms.Methods: Totally 120 male SD rats were randomly allocated into 4 groups(n=30): sham operated(Sham)group, SAH group, rapamycin group and BQ-123 group. The animal models were established by injecting the autologous blood into cisterna magna twice. Optical microscopy and electron microscopy were used to observe the morphological changes of neurons in hippocampus at different time point. The expressions of mTOR, Beclin-1 and LC3-Ⅱ protein in hippocampus of rat brain were detected by immunohistochemistry and RT-PCR. Apoptotic cells were detected by TUNEL.Results: In SAH group, the neurons showed degeneration, edema and death; the vascular endothelial cells were swollen, with compressed and stenotic lumen, tortuous vessel wall, disrupted connections, loose, obscure or even ruptured basilar membrane. In rapamycin group, most cells arranged orderly with structural integrity; vascular endothelial cells showed less swelling and agglutination, less compression and stenotic lumen. In BQ-123 group, structural integrity neurons increased; most vascular endothelial cells showed intact and distinct membrane and basilar membrane with uniform thickness. Compared with the SAH group, the expression level of mTOR mRNA decreased, and the expression levels of Beclin-1 and LC3-Ⅱ increased, and the number of apoptotic cells decreased in hippocampus of the rapamycin group and BQ-123 group(P＜0.05).Conclusion: BQ-123 can inhibit the apoptosis of neural cells in SAH, which is related to regulating mTOR/autophagy signaling pathway