滋阴泻火方对性早熟模型大鼠下丘脑-垂体-性腺轴的影响

Regulative Actions of Chinese Herbal Medicine for Nourishing Yin and Purging Fire in Precocious Puberty Model Rats Hypothalamic-pituitary-gonadal axis' function

目的:观察滋阴泻火方对性早熟大鼠下丘脑-垂体-性腺轴功能的影响。方法:26d雌性SD大鼠60只,随机分成正常对照(N)组、性早熟模型(P)组、亮丙瑞林(L)组、中药大剂量(C-H)组、中药中剂量(C-M)组和中药小剂量(C-L)组。除N组外,其余组建立由N-甲基-DL-天冬氨酸(NMA)诱导的性早熟大鼠模型。L组、C-H组、C-M组和C-L组在建立模型的同时,分别用L、C-H、C-M及C-L进行干预。测定各组大鼠卵巢、子宫指数,卵巢黄体出现率,下丘脑GnRH mRNA和垂体GnRH-R mRNA表达水平。结果:①与N组比较,P组、C-L组上述观察指标显著升高(P＜0．05),而L组、C-H组和C-M组未见统计学差异(P＞0．05)。②与L组比较, C-H组、C-M组以上指标未见统计学差异(P＞0．05)。结论:滋阴泻火方能抑制NMA诱导的雌性大鼠性早熟的发生,并使其维持在正常青春前期状态,其作用与亮丙瑞林相似。其干预机制可能是通过下调下丘脑GnRH和垂体GnRH-R基因的表达,从而抑制下丘脑—垂体—性腺轴的功能来实现的。

Objective： To observe the effects of Chinese herbal medicine （CHM） for nourishing Yin and purging Fire on the function of the hypothalamic- pituitary - gonadal axis （HPGA） in the precocious puberty model female rats. Methods： 60 26- day-old SD female rots were randomly assigned to six groups. They were normal control group （N）, precocious puberty model group（P）, Leuprorelin treatment group（L）, high-dose CHM treatment group （C-H）, middle-dose CHM treatment group （C-M） and low-dose CHM treatment group （C-L）. Group P, L, C-H, C-M and C-L were induced to precocious puberty by NMA. In the meantime, group L was administered Leuprorelin, and group C-H, C-M and C-L were administered 30ml_~g, 15ruing and 7.5mL/kg CHM respectively. The group P rats were decapitated at the first day of proestrous. The rest groups were killed at the same day with group P. The parameters of puberty were analyzed, which included the expression level of hypothalamic GnRH mRNA and pituitary GnRH-R mRNA （determined by real time RT-PCR）, the ovary index, the uterus index and the corpora luteum index. Results： （1）Compared with the group N, the expression level of hypothalamic GnRH mRNA and pituitary GnRHR mRNA, the ovary index and the uterus index were higher in the group P （P〈0.05）, but were not seen significant differences in group L, C-H and C-M （P〉0.05）. （2）Compared with the group L, the above parameters were not seen significant differences in groups C-H and C-M （P〉0.05）. Conclusions： （1）CHM for nourishing Yin and purging Fire ,as well as Leuprorelin, were able to inhibit the occurrence of the true precocious puberty induced by NMA in female rats, and remain the rats in normal prepuberty status. （2）These inhibition effects were caused by reducing the synthesis and release of GnRH, and lowing the responsibility of pituitary GnRH-R to GnRH. This may be the primary mechanism of CHM in effectively treating the true precocious puberty.