Regulative Actions Of Chinese Herbal Medicine For Nourishing Yin And Purging Fire In Precocious Puberty Model Rats

Objective: Observe the effects of Chinese herbal medicine (CHM) for nourishing Yin and purging Fire on the function of the hypothalamic- pituitary - gonadal axis (HPGA)and bone density in the NMA induced CPP model female rats. Access treatment effect and probe the treatment mechanism of CPP by CHM.Methods:60 26-day-old SD female rats were randomly assigned to six groups. They are normal control group (N), precocious puberty model group(P), Leuprorelin treatment group(L), large-dose CHM treatment group (C-L), middle-dose CHM treatment group (C-M) and low-dose CHM treatment group(C-low). P, L, C-L, C-M and C-low groups were induced to precocious puberty by NMA. They were subcutaneously administered 40mg/kg of NMA in saline twice a day (pm 2:00, 4:00).In the meantime, L group were subcutaneously administered 100μg/kg of Leuprorelin in saline once a day, and C-L, C-M and C-low groups were intragastrically administered 30ml/kg, 15 ml/kg and 7.5ml/kg CHM once a day respectively. The P group rats were decapitated at the first day of these proestrous. The rest groups were killed at the same day on decapitation of the P group. 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, the corpora luteum index and tibia bone density (BD, determined by PQCT, including total BD, trabecularBD and cortical BD).Results:①Compared with the N group, the expression level of hypothalamic GnRH mRNA and pituitary GnRH-R mRNA, the ovary index, the uterus index, and bone density (trabecular BD) were higher in the P group (P<0.05), but were not seen significant differences in L, C-L and C-M groups (P>0.05).②Compared with the P group, the above parameters were lower in L, C-L and C-M groups (P<0.05), but were not seen significant differences in C-low group (P>0.05).③Compared with the L groups, the above parameters were not seen significant differences in C-L and C-M groups (P>0.05).④C-L group and C-M group were compared with each other, the above parameters were not seen significant differences (P>0.05). Conclusions:①The NMA induced precocious puberty rat model is ture precocious puberty model.②Large dose CHM and middle dose CHM can able to inhibit the occurrence of the true precocious puberty induced by NMA in femal rats, and remain the rat's gonada and BD in normal prepuberty level.③Compare with the Leuprorelin group, Large dose CHM and middle dose CHM have the seem actions in the inhibitions of NMA induced rat model.④Between the large dose CHM and the middle dose CHM, there didn't exit a quantitiy-effect relationship.⑤CHM for nourishing Yin and purging Fire can inhibit the abnormal hyperfunction of HPGA in precocious puberty rat induced by NMA via reducing the synthesis and release of GnRH, and lowering the responsibility of pituitary GnRH-R to GnRH. This may be the primary mechanism of CHM in effectively treating the true precocious puberty.