miR-21调控PTEN及PDCD4基因治疗化疗性卵巢早衰

Lentivirus-mediated miR-21 alleviates cyclophosphamide-induced ovary damage by targeting PTEN and PDCD4 genes

目的:探讨miR-21在化疗性卵巢早衰大鼠模型中的治疗潜能及其可能机制。方法:体外构建miR-21慢病毒载体(LV-miR-21)。将大鼠随机分为空白对照组、模型组、空载组及miR-21组,通过腹腔注射环磷酰胺(CTX)建立化疗所致卵巢早衰大鼠模型。建模后往miR-21组大鼠双侧卵巢注射LV-miR-21,注射后第1、15、30、45、60天分批处死大鼠。阴道脱落细胞涂片检测大鼠动情周期;化学发光法与免疫放射法测定性激素水平;进行卵巢称重、计数各级卵泡数;TUNEL法测定卵巢组织颗粒细胞凋亡率;qRT-PCR、Western blot法检测miR-21靶基因PTEN、PDCD的mRNA及蛋白水平。结果:体外成功构建miR-21慢病毒载体。实验结束时,miR-21组有64%(16/25)大鼠恢复规律动情周期。注射后第15、30、45、60天,miR-21组的E_2水平、卵巢颗粒细胞凋亡率均高于模型组和空载组(P=0.000),FSH水平以及PTEN、PDCD4的mRNA、蛋白表达较相应时间点的模型组和空载组显著下降(P=0.000)。注射后第30、45、60天,miR-21组的卵巢重量显著高于模型组和空载组,但仍低于空白对照组;注射后第45、60天,miR-21组各级卵泡数均多于模型组和空载组(P=0.000);结论:miR-21在化疗诱导卵巢早衰大鼠模型中具有治疗潜能,其具体作用机制可能与下调靶基因PTEN、PDCD4有关。

Objective：To investigate the potential therapeutic effect and the possible mechanisms of miR-21 in chemotherapy-induced premature ovarian failure（POF） rats.Methods：Lentivirus-mediated miR-21（LV-miR-21） was constructed in vitro.Rats were randomly divided into 4 groups,named control group,model group,lentivirus（LV） group and miR-21 group.Rat models of chemotherapy-induced POF were established by intraperitoneal injection of cyclophosphamide（CTX）.After the successful establishment of chemotherapy-induced POF model,bilateral ovaries of miR-21 group were injected with lentivirus-mediated miR-21.At the day 1,15,30,45 and 60 after the last injection,rats were killed in batch.Estrous cycle changes were detecting.Chemiluminescence and radioimmunoassay were used to determine the sexual hormone levels.The ovary weights were measured by scale and the follicles were counted under microscopy.The apoptosis of ovarian granulosa cells was analyzed by TUNEL assay.The mRNA and protein levels of phosphatase and tensin homolog on chromosome ten（PTEN） and programmed cell death 4（PDCD4） were detected using qRT-PCR and Western blot,respectively.Results： LV-miR-21 was constructed successfully in vitro.At the end of the experiment,estrous cycle of 64%（ 16/25） rats in miR-21 group recovered.At 15,30,45 and 60 days after last injection,E2 level and granulosa cells apoptosis rates of miR-21 group were higher than model group and LV group（P=0.000）.Meanwhile,FSH level and mRNA and protein levels of PTEN,PDCD4 were lower than that of model and LV groups（P=0.000）.At 30,45,60 days after last injection,ovary weights of miR-21 group were significantly increased compared with model and LV groups,and were decreased compared with control group（P=0.000）.At 45 and 60 days after last injection,the number of developing follicles in miR-21 group was higher than model and LV groups（P=0.000）.Conclusions： The mechanism of therapeutic potential of LV-miR-21 may involve down-regulated expression of PTEN and PDCD4 targeted by miR-21.