The Effect of Herbal Medicine on Nerve Growth Factor in Estradiol Valerate-induced Polycystic Ovaries in Rats

A type of polycystic ovary resembling some aspects of human polycystic ovarian syndrome (PCOS) can be induced in the rat with a single injection of long-acting estradiol valerate. Among several theories behind the development of polycystic ovaries (PCO), the involvement of the sympathetic nervous system draws much attention, and herbal medicine is known to relieve the abnormal symptoms of PCO. Two herbal formulas, Changbudodam-Tang (cang fu dao tan tang) and Yongdamsagan-Tang (long dan xie gan tang), were used in the present study. The administration of herbal medicine was done every other day for 60 days. The morphological changes of ovaries from herbal medicine treatment were compared to those from an oil-treated control group and an estradiol valerate-injected group. This study also examined the possible hypothesis of neurogenic participation in terms of nerve growth factor (NGF) in the pathology of ovarian dysfunction. The nerve growth factor was analyzed in the central nervous system and ovaries by immunohistochemistry. The main findings of the present study were: (1) PCO were fully developed in rats with a single intramuscular injection of estradiol valerate, (2) PCO resulted in the expression of NGF in the ovaries and the brain tissues, and (3) herbal medicine administration significantly decreased the elevated NGF staining in the ovaries without affecting the brain tissues significantly.