摘要
目的探讨CAAT增强子结合蛋白同源蛋白(CHOP)、海马葡萄糖调节蛋白78(GRP78)和caspase-12在蛛网膜下腔出血(SAH)后的表达及其在早期脑损伤(EBI)中的作用。方法选取健康雄性SD大鼠78只,采用随机数字表法将其分为空白对照组(6只)、假手术组(36只)与SAH组(36只)。将假手术组和SAH组分别于1、6、12、24、48、72h,采用简单随机抽样法选取6只大鼠,神经功能缺陷评分后处死。比较各组不同时间点光镜及电镜下大鼠海马神经元形态改变、CHOP、GRP78、caspase-12相对表达水平、海马神经元凋亡细胞水平、脑水肿严重程度及神经功能缺陷评分情况。结果通过Western blot法检测CHOP、GRP78和caspase-12的表达,SAH组与空白对照组、假手术组在12、24、48、72h比较,差异均有统计学意义(P<0.05),且在SAH后24h达到峰值。TUNEL法检测大鼠海马区神经元凋亡显示,SAH组与对照组、假手术组在6、12、24、48、72h比较,差异均有统计学意义(P<0.05),在电镜下,SAH后24h节点可见明显的神经元凋亡。SAH组12、24、48、72h的神经功能缺陷评分及脑水肿程度明显重于空白对照组及假手术组,在24h达高峰,差异均有统计学意义(P<0.05)。SAH组大鼠的CHOP、GRP78和caspase-12 Western blot法检测结果与脑水肿严重程度及神经元凋亡结果之间呈极显著正相关,与神经功能缺陷评分呈极显著负相关(P<0.05)。结论 SAH后72h内确实造成了EBI,同时发生了内质网应激,内质网应激与EBI严重程度之间均呈正相关,揭示内质网应激在SAH后EBI的病理过程中发挥了重要作用。
Objective To investigate the role of the CAAT enhancer binding protein homologous protein( CHOP),hippocampus glucose regulated protein 78( GRP78) and caspase-12 in the early brain injury( EBI) after subarachnoid hemorrhage( SAH).Methods A total of 78 healthy male SD rats were randomly divided into the blank comparison group( 6 rats),sham operation group( 36 rats) and SAH group( 36 rats). 6 rats in the sham operation group and the SAH group were selected at 1,6,12,24,48,and 72 h respectively. These rats were sacrificed after a neurological deficit score. Compared the morphological changes of hippocampal neurons in rats at different time points under light microscope and electron microscope,CHOP,GRP78,caspase-12 relative expression level,hippocampal neuron apoptosis,brain edema severity and neurological deficit score. Results The expression of CHOP,GRP78 and caspase-12 was measured by Western blot,the SAH group was compared with the blank comparison group and the sham operation group,the difference was statistically significant( P < 0. 05) at 12,24,48,and 72 h,and reached the peak at 24 h after SAH. Detection of hippocampal neuronal apoptosis by TUNEL showed there was significant difference( P < 0. 05) at 6,12,24,48,72 h between SAH group and comparison group,sham operation group. Under electron microscope,obvious neuronal apoptosis was observed at the 24 h node after SAH. The neurological deficit scores and the degree of brain edema in SAH group were significantly higher than those in the blank comparison group and the sham operation group at 12,24,48 and 72 h,and reached the peak at 24 h,the difference was statistically significant( P <0. 05). In SAH group,there was a significant positive correlation between the results of CHOP,GRP78 and caspase-12 and the severity of brain edema and neuronal apoptosis,and there was a significant negative correlation with neurological deficit scores( P < 0. 05).Conclusion EBI and ER stress do exist in 72 h after SAH,and there is a positive correlation between ER stress and the severity of EBI.It reveals that ER stress play an important role in the pathological process of EBI after SAH.
引文
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