二甲双胍对多囊卵巢综合征大鼠氧化应激及细胞凋亡的影响

Effects of metformin on oxidative stress and apoptosis of rats with polycystic ovary syndrome

目的研究二甲双胍对多囊卵巢综合征(PCOS)大鼠氧化应激及细胞凋亡的影响。方法将SD大鼠分为4组,每组8只:正常组、PCOS组、MET组和LY294002组。正常组大鼠不进行任何干预,PCOS组大鼠用来曲唑灌胃建立PCOS模型,MET组PCOS大鼠用二甲双胍治疗,LY294002组PCOS大鼠用二甲双胍与LY294002同时治疗。治疗完成后检测各组大鼠体质量,血清HOMA-IR、总抗氧化能力(TAC)、睾丸激素(T)、黄体生成素(LH)和乳酸脱氢酶(LDH)水平及卵巢组织谷胱甘肽过氧化物酶(GPX)、过氧化氢酶(CAT)、超氧化物歧化酶(SOD)和丙二醛(MDA)水平;HE染色观察卵巢组织病变,TUNEL染色观察卵巢组织细胞凋亡状况;Western blot检测卵巢组织Bax及Bcl-2蛋白表达水平。结果与正常组相比,PCOS组体质量、血清T、LH、LDH水平及HOMA-IR、TAC水平显著升高,卵巢组织中MDA含量上升,SOD、GPX、CAT活性显著降低(均P<0.05);卵巢组织形态学改变且TUNEL阳性细胞率显著上升,Bax蛋白表达水平上升,Bcl-2蛋白表达水平下降(均P<0.05)。与PCOS组相比,MET组大鼠体质量、血清T、LH、LDH水平及HOMA-IR、TAC水平显著降低,卵巢组织中MDA含量下降,SOD、GPX、CAT活性显著上升(均P<0.05);卵巢组织病变减轻且TUNEL阳性细胞率显著降低,Bax蛋白表达水平下降,Bcl-2蛋白表达水平上升(均P<0.05)。与MET组比较,LY294002组大鼠体质量、血清T、LH、LDH水平及HOMA-IR、TAC水平显著升高,卵巢组织中MDA含量上升,SOD、GPX、CAT活性显著降低(均P<0.05);卵巢组织病变加重且TUNEL阳性细胞率显著上升,Bax蛋白表达水平上升,Bcl-2蛋白表达水平下降(均P<0.05)。结论二甲双胍能通过降低PCOS大鼠体质量,血清HOMA-IR、T、LH、TAC、LDH从而改善糖代谢水平;通过降低卵巢组织MDA,升高CAT、GPX、SOD水平从而抑制氧化应激;通过改善卵巢组织病变,降低TUNEL阳性细胞率、Bax蛋白表达水平,提高Bcl-2蛋白表达水平,从而抑制细胞凋亡。LY294002能逆转二甲双胍对PCOS大鼠的治疗作用。

Objective To study the effects of metformin on oxidative stress and apoptosis in rats with polycystic ovary syndrome(PCOS).Methods SD rats were divided into 4 groups with 8 rats in each group:normal group,polycystic ovary syndrome group,MET group,LY294002 group.Rats were not interfered in normal group,and rats were given oral administration of letrozole to establish PCOS model in PCOS group.PCOS rats were treated with metformin in MET group,and given simultaneously metformin and LY294002 in LY294002 group.After treatment,all rats were weighed,the insulin resistance index(HOMA-IR)was calculated,and serum levels of testosterone(T),luteinizing hormone(LH),total antioxidant capacity(TAC),lactate dehydrogenase(LDH)and levels of malon-dialdehyde(MDA),enzyme activity of activity catalase(CAT),glutathione peroxidase(GPX),and superoxide dismutase(SOD)in ovarian tissues were measured.HE and TUNEL staining were used to observe the ovarian tissue.The expression levels of Bax and Bcl-2 proteins in ovarian tissue were detected by Western blot.Results Compared with normal group,the levels of body weight,HOMA-IR,and serum levels of T,LH,LDH and TAC in PCOS group were increased significantly,the content of MDA was also increased in ovarian tissue,the levels of SOD,GPX and CAT activity were decreased significantly in ovarian tissues(all P<0.05),the morphology of ovarian tissue chaged,TUNEL positive cells were significantly increased,Bax protein expression level was increased,and Bcl-2 protein expression level was decreased(all P<0.05).Compared with PCOS group,the weight,serum T,LH,LDH,TAC levels and HOMA-IR in MET group were significantly reduced,and the activities of SOD,GPX,CAT in ovarian tissues were significantly increased,the content of MDA was reduced(all P<0.05);the pathological changes of ovarian tissue were alleviated and the TUNEL positive cells were significantly increased in ovarian tissue;Bax protein expression was increased and Bcl-2 protein expression was decreased in ovarian tissues(all P<0.05).Compared with MET group,the weight,serum T,LH,LDH,TAC levels and HOMA-IR in LY294002 group were significantly increased,and the activities of SOD,GPX,CAT in ovarian tissues were significantly reduced,the content of MDA was enhanced(all P<0.05);the morphology of ovarian tissue got worse and the TUNEL positive cells were significantly increased;and Bax protein expression was increased and Bcl-2 protein expression was decreased(all P<0.05).Conclusion Metformin can improve the glucose metabolism by reducing body weight,HOMA-IR,and serum levels of T,LH,TAC,LDH in PCOS rats,can inhibit the oxidative stress by decreasing MDA and increasing CAT,GPX and SOD levels in ovarian tissues,and can inhibit the apoptosis of ovarian cells by improving the pathological changes of ovary,decreasing the TUNEL positive cells,the expression of Bax protein and increasing the expression of Bcl-2 protein.LY294002 can reverse the therapeutic effect of metformin on PCOS rats.