牛磺酸对大鼠急性脑缺血神经元凋亡的影响

Effect of taurine on acute ischemia-induced neuron apoptosis in rats

目的从细胞凋亡的角度探讨急性脑缺血后牛磺酸的保护作用及作用机制。方法采用大脑中动脉线栓法(MCAO)和氧糖剥夺模型(OGD)复制在体和离体的大鼠急性脑缺血模型;采用荧光定量逆转录聚合酶链反应(real-tim efluorescence quantitative reverse transcriptase-polym erase chainreaction,real-tim e FQRT-PCR)检测Caspase-3/8的mRNA表达;流式细胞术(flow cytom etry,FCM)检测细胞凋亡;用Fura2/AM荧光探针检测细胞内游离钙离子浓度(intracellu larcalc ium concentrations,[Ca2+]i)变化。结果MCAO可以引起大鼠脑内caspase-3/8 mRNA表达上调,OGD使培养神经元[Ca2+]i上升,与OGD模型中凋亡神经元数量增多一致。牛磺酸可以减少细胞凋亡数量,抑制Caspase-3 mRNA表达上调及[Ca2+]i的升高。结论急性脑缺血后皮质神经元caspase-3/8的mRNA表达上调和[Ca2+]i增加可能与脑缺血后神经元凋亡有关;牛磺酸可以减少急性脑缺血后神经元凋亡,该作用与影响凋亡相关蛋白酶Caspase-3/8的基因表达及[Ca2+]i水平有关。

Aim To investigate the effect taurine on ischemia-induced neuron apoptosis and its mechanisms. Methods Focal cerebral ischemia was induced by middle cerebral artery occlusion （MCAO）. After 6 h permanent MCAO, mRNA of rat brain were detected expressions of Caspase-3/8 with real-time quantitative reverse transcriptase-polymerase chain reaction （realtime QRT-PCR）. Oxygen-glucose deprivation （OGD） was used to induce an tn vitro ischemia model. Primarily cultured cortical neurons were exposed to 4 h OGD. Intracellular calcium concentrations （ [ Ca^2＋ ] ） was measured with fluorescent Ca^2＋ sensitive probe fura 2 acetoxylmethyl ester （Fura 2/AM）. Neuronal apoptosis was assayed with flow cytometry of FITC-annexinV/propidium iodide binding 24 h after OGD. Resuits mRNA expressions of Caspase-3/8 were upregulated in MCAO model. [ Ca^2＋ ]; and neuronal apoptosis were markedly increased in OGD model. Taurine pretreatment reduced the upregulation of mRNA expression of Caspase-3/8 in vivo and ameliorated calcium overload and neuronal apoptosis in vitro. Conclusion Taurine has neuroprotective effect against ischema-induced neuronal apoptosis. This is partly due to its effects on Caspase-3/8 and [ Ca^2＋ ].