雌激素对一氧化碳中毒小鼠脑白质脱髓鞘的抑制作用及机制研究

Research of the Effect of Estrogen on BNIP3-mediated Apoptosis of Oligoendrocytes Induced by Carbon Monoxide Poisoning

目的:探讨雌激素对于一氧化碳(CO)中毒引起BNIP3介导的少突胶质细胞凋亡的抑制作用。方法:选用C57BL/6小鼠建立CO中毒动物模型,将30只雄鼠用随机数字表法分为6组(n均=5):正常对照组(Control组)、CO染毒组(CO组)、雌激素预防组(E2+CO组)、雌激素治疗组(CO+E2组)、雌激素预防加治疗组(E2+CO+E2组)、溶剂组(B+CO+B组)。分别采用免疫组织化学染色法和蛋白免疫印迹法检测小鼠脑组织内MBP、BNIP3、Bcl-2、和Caspase-3蛋白的表达,并分析各组间的差异。结果:与Control组相比,CO组的髓鞘结构明显脱失,E2+CO组的髓鞘脱失现象有所改善,但仍与Control组有较大差别,CO+E2组和E2+CO+E2组的髓鞘脱失现象有明显改善,接近于Control组,B+CO+B组的髓鞘脱失现象与CO组相接近。与Control组比较,CO组MBP表达明显降低(P<0.05),E2+CO组MBP表达较CO组有所回升(P<0.05),但仍低于Control组,CO+E2组和E2+CO+E2组MBP表达较CO组明显回升(P<0.05),均接近于Control组(P>0.05);与Control组比较,CO组BNIP3和cleaved-Caspase-3表达明显升高(P<0.05),E2+CO组BNIP3和cleaved-Caspase-3表达较CO组降低(P<0.05),但仍高于Control组,CO+E2组和E2+CO+E2组BNIP3和cleaved-Caspase-3表达较CO组明显降低(P<0.05),接近于Control组。同时,与Control组比较,CO组Bcl-2表达明显降低(P<0.05),E2+CO组Bcl-2表达较CO组升高(P<0.05),但仍低于Control组,CO+E2组和E2+CO+E2组Bcl-2表达较CO组明显升高(P<0.05),接近于Control组(P>0.05)。结论:雌激素对于CO中毒后小鼠脑白质脱髓鞘具有保护作用,其机制可能是通过抑制BNIP3表达,调控Bcl-2和Caspase-3介导的凋亡通路实现的。

Objective:To investigate the inhibitory effect of estrogen on BNIP3-mediated oligodendrocyte apoptosis induced by carbon monoxide(CO)poisoning.Method:C57BL/6 mice were selected to establish the animal model of CO poisoning treated by estrogen.30 male mice were divided into 6 groups(n=5)by random number table:normal control group(Control group),CO poisoning group(CO group),estrogen prophylaxis group(E2+CO group),estrogen treatment group(CO+E2 group),estrogen prophylaxis plus treatment group(E2+CO+E2 group)and solvent group(B+CO+B group).The expressions of MBP,BNIP3,Bcl-2,and Caspase-3 proteins in the brain tissues of mice were detected by immunohistochemical staining and western blot,respectively,and the differences of each component were analyzed.Results:Immunohistochemical results showed that compared with the Control group,the myelin structure of the CO group was significantly demyelin,and the myelin structure of the E2+CO group was improved,but there was still a big difference from the Control group.The myelin structure of the CO+E2 group and E2+CO+E2 group were significantly improved,close to the Control group.The demyelination of myelin in B+CO+B group was similar to that in CO group.Compared with the Control group,the expression of MBP in the CO group was significantly decreased(P<0.05),and the expression of MBP in the E2+CO group was higher than that in the CO group(P<0.05),but still lower than that in the Control group.MBP expression in CO+E2 and E2+CO+E2 groups increased significantly compared with CO group(P<0.05),and was close to that in Control group(P>0.05).Compared with the Control group,the expression of BNIP3 and cleaved-Caspase-3and in the CO group were significantly increased(P<0.05),and the expression of BNIP3 in the E2+CO group was decreased(P<0.05),but still higher than that in the Control group.The expression of BNIP3 and cleaved-Caspase-3 in CO+E2 and E2+CO+E2 groups were significantly lower than that in CO group(P<0.05),and close to that in Control group(P>0.05).Compared with the Control group,the expression of Bcl-2 in the CO group was significantly decreased(P<0.05),and the expression of Bcl-2 in the E2+CO group was increased(P<0.05),but still lower than that in the Control group.The expression of Bcl-2 in CO+E2 group and E2+CO+E2 group was significantly higher than that in CO group(P<0.05),and close to that in Control group(P>0.05).Conclusion:Estrogen has a protective effect on the demyelination of white matter in mice after CO poisoning,which may be achieved by inhibiting the expression of BNIP3 and regulating the apoptosis pathway mediated by Bcl-2 and Caspase-3.