雌二醇对萘处理去势雌性大鼠晶状体上皮细胞端粒酶活性与凋亡的作用

摘要

Objective To explore the effects of estradiol on the telomerase activity and apoptosis of lens epithelial cells and its mechanisms.Methods Fifty adult female Sprague-Dawley rats were randomly divided into five groups (n =10):ovariectomized group,estradiol group 1,estradiol group 2,estradiol group 3 and sham group.All rats were prepared for ovariectomized models except that of the sham group.After 2 weeks of the operation,rats in the 5 groups were given naphthalene solution through a stomach tube,and meanwhile,estradiol group 1,estradiol group 2,estradiol group 3 received estradiol valerate with the dose of 0.21 mg · kg-1 · d-1,0.42 mg · kg-1 · d-1 and 0.84 mg · kg-1 · d-1,accordingly,while rats in the ovariectomized group and sham group were given 9 g · L-1 Nacl by stomach perfusion with a dose of 0.42 mg · kg-1 ·d-1.Then,the opacity of the lens in each group was examined by a slit lamp microscope every week.After 12 weeks of naphthalene solution administration,all rats were sacririced and the serum estradiol concentration was determined by radioimmunoassay.Next,the lenses were taken out,and TERT mRNA expression of lens epithelial cells (LEC) was measured by RT-qPCR,and finally,the apoptotic rate was detected by TUNEL method.Results The opacity of lens in the ovariectomized group was different from that in the estradiol group 1,estradiol group 2,estradiol group 3 and sham group,with statistical significances (all P ＜ 0.05),and the opacity of lens in the estradiol group 1,2,3 and sham group were mild and occurred later.The serum estradiol concentration in the ovariectomized group (8.19 ± 1.45)ng · L-1 was significantly lower than that of estradiol groupl,2,3 and sham group,and there were significant differences (all P ＜ 0.05).Thc relative expression of TERT mRNA in LEC in the ovariectomized group (0.371 2-±0.056 4) was significantly lower than that in estradiol group 1,2,3,but the apoptotic rate of LEC (0.602 1 ±0.010 8) was obviously higher than that of estradiol group 1,2,3 in a dose-dependent manner,and there were significant differences (all P ＜ 0.05).Pearson correlation analysis showed the relative expression of LEC TERT mRNA in rats was negatively correlated with the apoptosis rate(r =-0.859,P ＜ 0.05).Conclusion Estradiol can up-regulate TERT mRNA expression and enhance telomerase activity of LEC in naphthalene-induced ovariectomized female rats in a dose-dependent manner.Estradiol can inhibit the LEC apoptosis in naphthalene-induced ovariectomized female rats,and the mechanism may be related to the increase of telomerase activity in the LEC.%目的 探讨不同浓度雌二醇对晶状体上皮细胞(lens epithelial cells,LEC)端粒酶活性与凋亡的作用及其机制.方法 将50只健康成年雌性SD大鼠随机分为5组:去势组、雌二醇1组、雌二醇2组、雌二醇3组和假手术组,除假手术组外,其余4组均行卵巢切除术,术后2周,5组均用萘混悬液灌胃,同时,雌二醇1组、雌二醇2组、雌二醇3组每天分别给予戊酸雌二醇0.21 mg· kg-1、0.42 mg·kg-1、0.84 mg·kg-1灌胃,去势组及假手术组每天均给予9g·L-1氯化钠溶液按0.42 mg·kg-1灌胃.每周观察各组大鼠晶状体混浊情况.灌胃12周后处死大鼠,采用放射免疫法检测大鼠血清中雌二醇浓度,采用RT-qPCR法检测LEC中端粒酶逆转录酶(telomerase reverse transcriptase,TERT) mRNA的水平,TUNEL法检测LEC的凋亡率.结果 12周时去势组的晶状体混浊情况同雌二醇1组、雌二醇2组、雌二醇3组及假手术组差异均有统计学意义(均为P ＜0.05).去势组血清雌二醇浓度为(8.19±1.45)ng·L-1,显著低于雌二醇各组,差异均有统计学意义(均为P ＜0.05).去势组大鼠LEC TERT mRNA相对表达量(0.371 2±0.056 4)显著低于雌二醇各组;去势组LEC凋亡率(0.602 1±0.010 8)明显高于雌二醇各组,差异均有统计学意义(均为P＜0.05),并且LEC TERT mRNA相对表达量和LEC凋亡率均与雌二醇浓度呈剂量依赖性变化.Pearson相关分析结果显示,LEC TERT mRNA相对表达量与LEC凋亡率间呈明显负相关(r=-0.859,P＜0.05).结论 雌二醇能上调萘处理去势雌性大鼠LEC TERT mRNA表达,增加端粒酶活性,且呈剂量依赖性.雌二醇可抑制萘处理去势雌性大鼠LEC凋亡,其机制可能与细胞中端粒酶活性增加有关.