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目的分析Kisspeptin-GPR54-GnRH信号通路在玉米赤霉烯酮(ZEA)诱导的雌性大鼠中枢性性早熟(CPP)中的作用机制,探究ZEA与大鼠CPP发生发展的相关性以及Kisspeptin-GPR54-GnRH信号通路在这一过程中的调节作用。方法选取雌性SD大鼠30只,随机分为正常青春前期组(A组)、青春期组(B组)和ZEA组(C组),每组各10只。C组每日灌胃400 mg/kg ZEA以建立CPP模型。观察各组阴道开放时间及性周期、子宫指数、卵巢指数、卵巢黄体出现率和子宫壁厚度;Real-Time-PCR法检测下丘脑中的KISS-1 mRNA、GPR54 mRNA和促性腺激素释放激素(GnRH)mRNA表达量;Western blot检测下丘脑中Kisspeptin、GPR54和GnRH蛋白表达水平。结果 C组大鼠性发育起始时间早于A组和B组,且各检测指标明显高于A组(P<0.05),但与B组比较,差异无统计学意义(P>0.05);随着青春期发育,B组和C组大鼠下丘脑中KISS-1、GPR54和GnRH在转录水平和翻译水平的表达量均逐渐升高。结论利用ZEA可诱导建立理想的雌性大鼠CPP模型,随着大鼠青春期的发育,下丘脑中KISS-1、GPR54和GnRH蛋白表达逐渐升高,表明Kisspeptin-GPR54-GnRH信号通路在CPP的发生和发展过程中发挥着重要作用。
Objective To investigate the mechanism of Kisspeptin-GPR54-GnRH signaling pathway in ZEA-induced central precocious puberty (CPP) in rats and to explore the association between ZEA and rat CPP development and the relationship between Kisspeptin-GPR54 Regulation of GnRH signaling pathway in this process. Methods Thirty female SD rats were randomly divided into normal preadolescent group (A group), adolescent group (B group) and ZEA group (C group), with 10 rats in each group. Group C was given 400 mg / kg ZEA daily to establish CPP model. Vaginal open time and sexual cycle, uterine index, ovarian index, ovarian corpus luteum appearance and uterine wall thickness were observed in each group. KISS-1 mRNA, GPR54 mRNA and gonadotropin-releasing hormone GnRH) mRNA expression levels; Western blot detection hypothalamus Kisspeptin, GPR54 and GnRH protein expression levels. Results The onset time of sexual development in group C was earlier than that in group A and group B, and each index was significantly higher than that in group A (P <0.05). However, there was no significant difference between group C and group B (P> 0.05). With adolescent development, the expression levels of KISS-1, GPR54 and GnRH in the hypothalamus of rats in group B and group C gradually increased at transcriptional and translational levels. Conclusions ZEA can induce the establishment of an ideal CPP model in female rats. With adolescent development, the expression of KISS-1, GPR54 and GnRH in the hypothalamus gradually increased, indicating that the Kisspeptin-GPR54-GnRH signaling pathway is involved in the pathogenesis of CPP And play an important role in the development process.