内质网应激对七氟醚麻醉术后认知功能障碍大鼠脑海马组织及神经元的影响

目的探讨七氟醚通过影响内质网应激对麻醉术后认知功能障碍(POCD)大鼠脑海马组织、神经元的影响及内质网应激抑制剂的干预作用.方法选择清洁级SD雄性大鼠24只,随机分为3组:A组(对照组)、B组(七氟醚组)、C组(七氟醚+内质网应激抑制剂4-苯基丁酸(4-PBA)组),每组8只.采用Morris水迷宫实验检测大鼠认知功能,采用苏木精-伊红染色观察各组大鼠脑海马组织病理形态学改变,采用流式细胞术检测脑海马神经元细胞凋亡数,采用ELISA法检测脑海马组织中脑源性神经营养因子(BDNF)、神经元特异性烯醇化酶(NSE)的表达水平,采用Western blot和qRT-PCR法检测脑组织Bcl-2相关X蛋白(Bax)、B淋巴细胞瘤-2(Bcl-2)、葡萄糖调节蛋白78(GRP78)、葡萄糖调节蛋白94(GRP94)、C/EBP同源蛋白(CHOP)、X-盒结合蛋白1(XBP1)表达水平.结果苏木精-伊红染色结果表明,与A组细胞,B组大鼠脑海马组织中细胞明显减少,层次不完整,分布不均匀,细胞排列紊乱;C组大鼠脑海马组织中细胞较B组增加,海马细胞排列紊乱现象有所改善.与A组相比,B组和C组大鼠逃避潜伏期长,平台所在象限停留时间及穿越平台次数显著减少(P<0.05);海马神经元细胞凋亡数显著增加,脑组织Bax、NSE、GRP78、GRP94、CHOP、XBP1表达水均显著升高而Bcl-2、BDNF表达水平显著降低(P<0.05).与B组相比,C组大鼠逃避潜伏期明显缩短,平台所在象限停留时间及穿越平台次数显著增加,海马神经元细胞凋亡数显著减少(P<0.05),其余各指标均有不同程度的改善.结论七氟醚可通过促进内质网应激引起大鼠脑海马组织损伤及神经元细胞凋亡水平增加,从而引起大鼠认知功能障碍;抑制内质网应激可改善七氟醚诱导的大鼠认知功能障碍.

Effects of endoplasmic reticulum stress on hippocampus and neurons in rats with postoperation cognitive dysfunction after sevoflurane anesthesia

Objective To explore the effect of sevoflurane on the hippocampus and neurons of rats with postoperation cognitive dysfunction(POCD)after anesthesia through the effect of endoplasmic reticulum stress and the intervention of endoplasmic reticulum stress inhibitors.Methods 24 SD male rats were randomly divided into three groups:group A(control group),-group B(sevoflurane group),group C(Sevoflurane+Endoplasmic reticulum stress inhibitor 4-phenylbutyric acid(4-PBA)group);8 rats in each group.Morris water maze test was used to detect the cognitive function of rats.Hematoxylin-eosin(HE)staining was used to observe the pathological changes of hippocampus.Flow cytometry was used to detect the number of apoptosis in hippocampal neurons.The expression of brain-derived neurotrophic factor(BDNF)and neuron-specific enolase(NSE)in hippocampus was detected by ELISA.Bcl-2 Associated X Protein(Bax),B-cell lymphoma-2(Bcl-2),gloucose requlated protein 78(GRP78),gloucose requlated protein 94(GRP94),C/EBP homology protein(CHOP)and X-box binding protein 1(XBP1)were detected by Western blot and qRT-PCR.Results The results of HE staining showed that compared with the cells in group A,the cells in the hippocampus of group B were significantly reduced,with incomplete layers,uneven distribution and disordered arrangement;the cells in the hippocampus of group C were more than those in group B,and the disordered arrangement of the cells in the hippocampus of group C was improved.Compared with group A,the escape latency of group B and group C was longer,and the time of staying in the quadrant where the platform was and the times of crossing the platform were significantly reduced(P<0.05).The number of apoptosis of hippocampal neurons increased significantly,and the expression of Bax,NSE,GRP78,GRP94,CHOP and XBP1 in brain tissue increased significantly,while the expression level of Bcl-2 and BDNF decreased significantly(P<0.05).Compared with group B,the escape latency of group C was significantly shortened,and the time of staying in the quadrant where the platform was and the times of crossing the platform were significantly increased(P<0.05).Other indicators have improved to varying degrees.Conclusion Sevoflurane can induce cognitive impairment in rats by promoting brain hippocampus injury and neuronal apoptosis induced by endoplasmic reticulum stress,and inhibition of endoplasmic reticulum stress can improve cognitive dysfunction induced by sevoflurane in rats.