宫内窘迫胎鼠脑组织葡萄糖调节蛋白78及胱冬酶9,12表达的改变

Changes of the expressions of endoplasmic reticulum chaperones GRP78 and caspase-9 and-12 in fetal rats with intrauterine distress

目的:探讨内质网分子伴侣葡萄糖调节蛋白(GRP)78及凋亡因子胱冬酶(caspase)-9,12在宫内窘迫致胎鼠脑缺血损伤中的作用。方法:制备胎鼠宫内窘迫模型,随机分为正常组(10只胎鼠)、假手术组(50只胎鼠)、缺血再灌注组(50只胎鼠)。胎鼠脑组织行TUNEL染色,分析神经元凋亡情况;免疫组化法检测海马回CA1区GRP78及caspase-9,12蛋白的表达。结果:①宫内窘迫缺血再灌注可导致胎鼠脑神经元凋亡,且凋亡数量随再灌注时间延长而增加。②正常组及假手术组仅有GRP78,caspase-9,12蛋白微弱表达;缺血再灌注组GRP78于再灌注3 h达峰值,之后逐渐下降;caspase-12于再灌注3 h内表达量急剧上升,至12 h达高峰;caspase-9则于血流恢复3 h之后表达迅速增强,至12 h达峰值。结论:宫内窘迫致胎鼠缺血缺氧性脑损伤可能与GRP78表达升高启动内质网自稳调节系统有关;内质网caspase-12凋亡通路的启动可能是脑缺血损伤的又一机制。

Objective： To investigate the role of glucose-regulated protein 78 （GRP78） and caspase-9 and-12 in intrauterine distress-induced hypoxic-ischemic cerebral damage in fetal rats. Methods： The fetal rat model of intrauterine distress was constructed and the fetal rats were randomly divided into a normal, a sham operation and an ischemia-reperfusion （IR） group. Neuron apoptosis was analyzed by in situ end-labeled DNA （TUNEL）. The expressions of caspase-9 and-12 and GRP78 proteins in the hippocampus CA1 area were detected by immunohistochemical staining. Results： Ischemia-reperfusion damage induced classic neuron apoptosis and the number of the apoptotic neurons in the hippocampus CA1 area increased with the progression of reperfusion. The expressions of GRP78 and caspase-9 and-12 were weak in the normal and sham operation group. In the IR group, the expression of GRP78 reached the peak value 3 hours after the reperfusion and then decreased gradually ; the intensity of caspase-12 was increased rapidly while that of caspase-9 elevated very little within 3 hours, but both reached the peak value at 12 hours. Conclusion： Intrauterine distress-induced hypoxic-ischemic cerebral damage in fetal rats may trigger the homeostatic control system in the endoplasmic reticulum through the increased expression of GRP78. The apoptotic pathway mediated by caspase-12 in the endoplasmic reticulum may be one of the mechanisms underlying cerebral ischemic injury.