Study On Effects Of Chinese Herbal Medicine For Nourishing Yin And Purging Fire In Nma-Induced CPP Model Of Female Rats

Objective: To observe the effect of Chinese herbal medicine (CHM) for nourishing Yin and purging Fire on the onset of puberty and on the function of the hypothalamus-pituitary-gonadal axis in the NMA-induced CPP model of female rats and to probe the treatment mechanism of CPP by CHM therapy.Methods: 50 26-day-old SD female rats were randomly assigned to the normal control group (n=10), the model group (n=10), the megestrol acetate(MA) group (n=10), the high-dose of CHM group (n=10) and the low-dose of CHM group(n=10). All Rats, except that in the normal group, were subcutaneously administered 40mg/kg of NMA in saline twice a day. In the meantime, the MA group, high-dose and low-dose of CHM groups received gavage of 0.3mg/kg MA, 20ml/kg and 12ml/kg CHM once a day respectively. The normal group fed with normal saline until vaginal opening (VO) occurred.. Vaginal smear was taken daily after VO to detect the first day of diestrus (D1) and the first day of proestrous. The normal and model groups were decapitated at the first day of its proestrous. Two CHM groups and the MA group were killed at the same day on decapitation of the model group. The parameters of puberty were analyzed, which including the expression level of GnRHmRNA of hypothalamus, the concentration of serum LH, the ovary index, the uterus index, the corpora luteum in the ovary and the wall depth of the uterus.Results: Compared with the normal group, the VO and D1 were advanced followed with regular estrous cycles in the model group, while there was no differences in the parameters of puberty between both groups. The parameters of puberty in high-dose and low-dose of CHM groups were no differences from the MA group, which were much lower than those in the model group. Conclusions: CHM for nourishing Yin and purging Fire may inhibit the function of hypothalmus-pituitary-gonadal axis(HPGA) and arrest the occurrence of the true precocious puberty induced by NMA in female rats. The inhibition to HPGA of CHM was similar to that of MA, which may be the primary mechanism of CHM in effectively treating true precocious puberty .