性早熟雌性Sprague-Dawle大鼠下丘脑Lin28a和Lin28b表达异常

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。

Abnormal Expression of Lin28a and Lin28b mRNA in Hypothalamus of Female Precocious Puberty Sprague-Dawle Rat

Objective：To investigate expression and significance of Lin28a and Lin28b mRNA in hypothalamus of female SD rats at various stages of development and precocious puberty induced by estrogen.Methods：1）Analyze expression of Lin28a and Lin28b mRNA in hypothalamus of SD rats with Real-time PCR on postnatal day 15（PND15）,PND23 and PND35,meanwhile examine level of serum LH and E2with ELISA;2）EB（estradiol benzoate）-induced precocious puberty rats are divided into EB-1 and EB-2 groups and are respectively sacrificed at the time of vaginal opening（VO）and PND56,at the same time respectively controlled with OIL-1 and OIL-2groups which are induced by sesame oil（OIL）.Analyze expression of Lin28a and Lin28b mRNA in hypothalamus with Real-time PCR,examine level of serum LH and E2with ELISA and observe influence of precious puberty on VO,weight,crown-rump length,tibia length at the same time.Results：1）Expression of Lin28a and Lin28b mRNA in hypothalamus and level of serum LH and E2among PND15,PND23 and PND35 groups are not statistically significant（P〉0.05）;2）Expression of Lin28a and Lin28b mRNA in EB-1 is higher than OIL-1（P〈0.05）,while level of serum LH and E2between two groups is not statistically significant（P〉0.05）;Expression of Lin28a and Lin28b mRNA in EB-2 is higher than OIL-2（P〉0.05）,meanwhile level of serum LH and E2between two groups is statistically significant（P〈0.05）;3）Time of VO in EB-2 group is earlier than OIL-2 group（P〈0.01）,while weight,crown-rump length,tibia length between two groups is not statistically significant（P〈0.05）.Conclusions：Precious puberty induced by Exogenous Estrogen could result in abnormal expression of Lin28a and Lin28b mRNA in hypothalamus.