雌激素对慢性间歇性低氧大鼠颏舌肌线粒体细胞色素C氧化酶活性及其亚基表达的影响

目的 通过研究雌激素对慢性间歇性低氧(chronic intermittent hypoxia,CIH)大鼠颏舌肌线粒体细胞色素C氧化酶(cytochreme C oxidase,COX)活性及其亚基(COX Ⅰ、COXⅣ)表达的影响,探讨阻塞性睡眠呼吸暂停低通气综合征(OSAHS)发病中雌激素所起的作用.方法 3个月龄健康雄性SD大鼠48只,分为正常对照组(NC组)、慢性间歇性低氧组(CIH组)及慢性间歇性低氧+雌激素干预组(E+CIH组).后两组建立CIH模型,同时E+CIH组给予苯甲酸雌二醇0.2 mg/kg,NC组、CIH组给予无菌橄榄油0.2 ml/次,2次/周,肌肉注射.密度梯度离心法分离大鼠颏舌肌线粒体,极谱法测量COX活性;Western blotting分析COX Ⅰ和COXⅣ蛋白表达;实时聚合酶链反应(real-time polymerase chain action)法检测COX Ⅰ和COXⅣ的基因表达.结果 CIH组大鼠颏舌肌线粒体COX活性为(0.143±0.029)μkat/mg,与NC组(0.273±0.058)μkat/mg]相比显著降低(P＜0.01),E+CIH组COX活性(0.203±0.073)μkat/mg]较CIH组有所回升(P＜0.05),但仍显著低于NC组(P＜0.05).CIH组与E+CIH组COX Ⅰ蛋白表达分别为(10.789±8.144)和(25.593±11.108),与NC组(47.325±7.502)相比均显著降低(P＜0.01),且E+CIH组COX Ⅰ蛋白表达显著高于CIH组(P＜0.05).3组COXⅣ蛋白表达的差异无统计学意义(P＞0.05);3组COX Ⅰ、COXⅣmRNA表达量的差异无统计学意义(P＞0.05).结论 CIH可抑制大鼠颏舌肌线粒体COX蛋白表达及活性,而雌激素干预可部分恢复COX蛋白表达及活性.

Effects of estrogen on activity and subunits expression of cytochrome C oxidase in mitochondria from genioglossus of rats subjected to chronic intermittent hypoxia

Objective To investigate the effects of estrogen on the activity and subunits expression of cytochrome c oxidase (COX) in mitochondria from genioglossus of chronic intermittent hypoxia (CIH)rat.Methods Forty-eight male Spragne-Dawley (SD) rats were randomly divided into three groups:the normal control group (NC),the chronic intermittent hypoxia group (CIH) and estrogen plus hypoxia group(E + CIH).Rats in the latter two groups were used to build CIH models(8 h/d,5 w).In the mean time,rats in NC group and CIH group were injected with sterile olive oil (0.2 ml each time, twice a week),and rats in E + CIH group were injected with estrogen (0.2 mg/kg,twice a week),respectively. At the end of the treatment,the genioglossus of the rat was removed and the mitechondrla were isolated by centrifugation program.COX activity was measured with a spectrophotometer.The protein content of COX subunit I and IV was detected by Western blotting analysis,and mRNA expression levels of COX Ⅰ and COX Ⅳ were determined by real-time polymerase chain action.Results COX activity in CIH group (0.143±0.029) μkat/mg] was lower significantly than that in NC group (0.273±0.058)μkat/mg, P＜0.01];In E + CIH group (0.203±0.073) μkat/mg],COX activity was higher than that in CIH group(P＜0.05),but still lower than that in NC group (P＜0.05).Compared with NC group (47.325±7.502),decreased COX I expression was observed in CIH group (10.789±8.144,P＜0.01) and E +CIH group (25.593 +11.108,P＜0.01).While in the mean time, the protein content of COX I in E +CIH group was higher than that in CIH group (P＜0.05).There was no significant difference in protein content of COXlV among the three groups (P＞0.05).COXI and COXIV mRNA levels had no significant change among the three groups (P＞0.05).Conclusions CIH exposure could decrease mitochondrial COX protein expression and activity in the genioglossns of the rat,while estrogen administration might be beneficial to the recovery of those.