沉默信息调节因子2相关酶1通过PINK1-Parkin线粒体自噬减轻创伤性脑损伤研究

Experimental study of silent mating-type information regulation 2 homolog 1 alleviating traumatic brain injury through PINK1-Parkin mediated mitophagy

目的探讨沉默信息调节因子2相关酶1(SIRT1)通过PINK1-Parkin线粒体自噬发挥在创伤性脑损伤(TBI)中的神经保护作用及机制。方法第一阶段实验,小鼠随机分为4组:空白组(野生型小鼠建立假模型后接受溶剂处理)、对照组(野生型小鼠建立假模型后接受20 mg/kg SRT1720处理)、模型组(野生型小鼠建立TBI模型后接受溶剂处理)、治疗组(野生型小鼠建立TBI模型后接受SRT1720处理)。第二阶段实验小鼠随机分为5组:空白组(野生型小鼠建立假模型后接受溶剂处理)、对照组(Parkin-/-小鼠建立假模型后接受溶剂处理)、模型组(野生型小鼠建立TBI模型后接受溶剂处理)、治疗组(野生型小鼠建立TBI模型后接受SRT1720处理)、敲除组(Parkin-/-小鼠建立TBI模型后接受SRT1720处理)。采用控制性皮层损伤法建立小鼠TBI模型。比较PINK1、Parkin、B淋巴细胞瘤-2(Bcl-2)、Bcl-2相关X蛋白(Bax)表达、脑水肿、神经功能及神经细胞凋亡情况。结果第一阶段,与空白组比较,模型组小鼠皮质组织中PINK1及线粒体Parkin表达显著增加,细胞质Parkin表达显著下降;与模型组比较,治疗组小鼠皮质组织中PINK1及线粒体Parkin表达显著增加,细胞质Parkin表达显著下降,差异均有统计学意义(P<0.05)。第二阶段实验,与空白组比较,模型组小鼠神经细胞凋亡率及Bax表达显著增加,Bcl-2表达显著下降;与模型组比较,治疗组小鼠神经细胞凋亡率及Bax表达显著下降,Bcl-2表达显著增加;与治疗组比较,敲除组小鼠神经细胞凋亡率及Bax表达显著增加,Bcl-2表达显著下降,差异均有统计学意义(P<0.05)。与空白组比较,模型组小鼠脑水肿及神经功能缺损评分(mNSS)显著增加;与模型组比较,治疗组小鼠脑水肿及mNSS评分显著下降;与治疗组比较,敲除组鼠脑水肿及mNSS评分显著增加,差异均有统计学意义(P<0.05)。结论SIRT1通过上调PINK1-Parkin线粒体自噬减轻TBI小鼠神经细胞凋亡,并改善神经功能障碍。

Objective To investigate the neuroprotective effect of silencing information regulator 2-related enzyme 1(SIRT1)through PINK1-Parkin mitophagy in traumatic brain injury(TBI)and its mechanism.Methods Mice were randomly divided into four groups in the first stage:blank group[wild type(WT)mice received a sham TBI model and treated with vehicle],control group(WT mice received a sham TBI model and treated with 20 mg/kg of SRT1720),model group(WT mice received a TBI model and treated with vehicle),treatment group(WT mice received a TBI model and treated with 20 mg/kg of SRT1720).Mice were randomly divided into five groups in the second stage:blank group(WT mice received a sham TBI model and treated with vehicle),control group(Parkin-/-mice received a sham TBI model and treated with vehicle),model group(WT mice received a TBI model and treated with vehicle),treatment group(WT mice received a TBI model and treated with 20 mg/kg of SRT1720),knock out(KO)group(Parkin-/-mice received a TBI model and treated with 20 mg/kg of SRT1720).The TBI model was established by the controlled cortical damage method.The expression of PINK1,Parkin,B lymphocytoma-2(Bcl-2),Bcl-2 associated X protein(Bax)cerebral edema,nerve function couples and nerve cell apoptosis were compared.Results In the first stage:compared with the blank group,the expression of PINK1 and mitochondrial Parkin in the model group were significantly increased,and the expression of cytoplasmic Parkin was significantly reduced;compared with the model group,the expression of PINK1 and mitochondrial Parkin in the treatment group were significantly increased,and the expression of cytoplasmic Parkin was significantly reduced,all the differences were statistically significant(P<0.05).In the second stage:compared with the blank group,the neural apoptotic ratio and Bax expression in the model group were significantly increased,the expression of Bcl-2 was significantly reduced;compared with the model group,the neural apoptotic ratio and Bax expression in the treatment group were significantly reduced,the expression of Bcl-2 was significantly increased;compared with the treatment group,the neural apoptotic ratio and Bax expression in the KO group were significantly increased,the expression of Bcl-2 was significantly reduced(P<0.05).Compared with the blank group,cerebral edema and modified neurological severity scores(mNSS)in the WT model group were significantly increased;compared with the model group,cerebral edema and mNSS scores in the treatment group were significantly reduced;compared with the treatment group,cerebral edema and mNSS scores in the KO group were significantly increased,and the differences were statistically significant(P<0.05).Conclusion SIRT1 attenuates neuronal apoptosis and improves neurological dysfunction in TBI mice by up-regulating PINK1-Parkin mitophagy.