上调的miR-132通过抑制FoxO1降低七氟醚对老龄大鼠认知功能损害作用

Up-regulated miR-132 reduces the effect of sevoflurane on cognitive impairment in aged rats by inhibiting FoxO1

目的探究miR-132对七氟醚(Sev)诱发的术后认知功能障碍(POCD)的影响与机制。方法取60只大鼠,随机分为对照(Con)组,七氟醚(Sev)组,七氟醚+miR-132(Sev+miR-132)组,七氟醚+miR-132+OE-NC(Sev+miR-132+OE-NC)组,七氟醚+miR-132+OE-Fox01(Sev+miR-132+OEFoxO1)组,每组12只。采用七氟醚麻醉4h行脾脏切除术构建POCD模型,造模前1d,取Sev+miR-132组大鼠侧脑室注射miR-132 mimic,Sev+miR-132+OE-NC组与Sev+miR-132+OE-FoxO1组大鼠分别额外注射OE-NC mimic与OE-FoxO1 mimic。次日,取各组大鼠开展水迷宫实验,共6d。完成后处死大鼠,取脑组织用于苏木精-伊红染色,TUNEL染色,荧光定量PCR与Western blot检测。结果与Sev组相比,Sev+miR-132组大鼠逃避潜伏期与首次到达平台时间减少,穿越平台次数与第Ⅲ象限停留时间增加。脑组织中,Sev+miR-132组Caspase-3,Bax mRNA含量减少,Bcl-2 mRNA含量增加,PI3K/Akt信号通路蛋白表达增加,FoxO1蛋白表达减少。此外,苏木精-伊红染色显示海马CA1区神经元状态恢复,TUNEL染色阳性细胞数减少。与此同时,与Sev+miR-132+OE-NC组相比,Sev+miR-132+OE-FoxO1组大鼠逃避潜伏期与首次到达平台时间增加,穿越平台次数与第Ⅲ象限停留时间减少,脑组织中Caspase-3,Bax mRNA含量增加,Bcl-2 mRNA含量减少。结论miR-132通过抑制FoxO1蛋白表达减轻神经元凋亡,从而改善七氟醚诱发的老龄大鼠术后认知功能障碍。

Objective To investigate the effect and mechanism of miR-132 on sevoflurane(Sev)-induced postoperative cognitive dysfunction(POCD).Methods 60 rats were randomly divided into Con group,Sev group,Sev+miR-132 group,Sev+miR-132+OE-NC group,and Sev+miR-132+OE-FoxO1 group,with 12 rats in each group.The POCD model was established by splenectomy under sevoflurane anesthesia for 4 hours.1 d before splenectomy,rats in the Sev+miR-132 group were injected with miR-132 mimic in the lateral ventricle,and the Sev+miR-132+OE-NC group and Sev+miR-Rats in the 132+OE-FoxO1 group were additionally injected with OE-NC mimic and OE-FoxO1 mimic,respectively.The day after splenectomy,the Morris water maze experiment was operated for6 days.Then,the rats were sacrificed,and the brains were collected for HE staining,TUNEL staining,fluorescence quantitative PCR and Western blot detection.Results Compared with the Sev group,the escape latency and the first arrival time to the platform of the rats in the Sev+miR-132 group decreased,while the number of platform crossing and the resident time in the III quadrant increased.In brains,Caspase-3 and Bax mRNA content decreased,Bcl-2 mRNA content increased,PI3K/Akt signaling pathway protein expression increased,and FoxO1 protein expression decreased in Sev+miR-132 group.In addition,HE staining showed that the state of neurons in the hippocampal CA1 region were restored,and the number of TUNEL staining-positive cells decreased which compared to Sev group.At the same time,compared with the Sev+miR-132+OE-NC group,the escape latency and the first arrival time to the platform in the Sev+miR-132+OE-FoxO1 group increased,the number of the platform crossing and the resident time in the Ⅲ quadrant decreased.In addition,the contents of Caspase-3 and Bax mRNA in brain increased,while the contents of Bcl-2 mRNA decreased.Conclusion miR-132 reduces neuronal apoptosis by inhibiting FoxO1 protein expression,thereby improving postoperative cognitive dysfunction in aged rats induced by sevoflurane.