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目的:研究正常雌性Sprague-Dawle(SD)大鼠不同性发育阶段及雌激素诱导性早熟后下丘脑Lin28a和Lin28b的表达及意义。方法:1)于雌性SD大鼠出生后15日(postnatal day 15,PND15)、PND23、PND35荧光实时定量PCR分析下丘脑Lin28a和Lin28b mRNA的表达,同时以ELISA法检测血清黄体生成素(LH)和雌二醇(E2)水平变化;2)苯甲酸雌二醇(estradiol benzoate,EB)诱导的性早熟大鼠随机分为EB-1组和EB-2组,分别于阴道开口(vaginal opening,VO)时及PND56两个时间点处死,相应的发育阶段的大鼠用无菌芝麻油(sesame oil,OIL)作为对照分为OIL-1和OIL-2组;荧光实时定量PCR分析下丘脑Lin28a和Lin28b mRNA的表达,ELISA法检测LH和E2水平变化,并观察性早熟对大鼠阴道开口、体重、顶臀径、胫骨长等生长发育指标的影响。结果:1)PND15、PND23和PND35组下丘脑Lin28a和Lin28b mRNA表达、血清LH和E2水平无统计学差异(P>0.05);2)EB-1组下丘脑Lin28a和Lin28b mRNA表达高于OIL-1组(P<0.05),血清LH和E2水平与OIL-1组相比无统计学差异(P>0.05);EB-2组下丘脑Lin28a和Lin28b mRNA表达高于OIL-2组(P<0.05),血清LH和E2水平低于OIL-2组(P<0.05);3)与OIL-2组比较,EB-2组VO时间明显提前(P<0.01),体重、顶臀长、胫骨长差异无统计学差异(P>0.05)。结论:外源性雌激素引起的性早熟可能导致下丘脑Lin28a和Lin28b表达异常。
AIM: To investigate the expression and significance of Lin28a and Lin28b in hypothalamus of normal female Sprague-Dawle (SD) rats at different developmental stages and estrogen-induced precocious puberty. Methods: 1) The expressions of Lin28a and Lin28b mRNA in the hypothalamus were detected by real-time quantitative PCR with PND15 and PND35 on the 15th day of postnatal day 15 (PND15) of female SD rats. Serum luteinizing hormone (LH) And estradiol (E2). 2) The precocious rats induced by estradiol benzoate (EB) were randomly divided into two groups: EB-1 group and EB-2 group, VO) and PND56 at two time points. Rats in the corresponding developmental stages were divided into OIL-1 and OIL-2 groups by using sterile sesame oil (OIL) as control. Fluorescence real-time quantitative PCR was used to analyze the expressions of Lin28a and The expression of Lin28b mRNA was detected by enzyme-linked immunosorbent assay (ELISA). The effects of precocious puberty on the growth, development of vagina, body weight, top hip diameter and tibia length were observed. Results: 1) The expressions of Lin28a and Lin28b mRNA in hypothalamus of PND15, PND23 and PND35 group were not significantly different (P> 0.05); 2) The expression of Lin28a and Lin28b mRNA in hypothalamus of EB-1 group was higher than that of OIL- (P <0.05). There was no significant difference in serum LH and E2 levels between the two groups (P> 0.05). The mRNA expressions of Lin28a and Lin28b in the hypothalamus of EB-2 group were higher than those in OIL-2 group (P < 0.05). The serum levels of LH and E2 were lower than those of OIL-2 group (P <0.05) .3) Compared with OIL-2 group, the VO time of EB-2 group was significantly earlier (P < There was no significant difference in length (P> 0.05). Conclusion: Exogenous estrogen-induced precocious puberty may lead to abnormal expression of Lin28a and Lin28b in hypothalamus.