13 month old female rats were randomly divided into 4 groups: the Saline group, the LPP groups treated by low (1.67 g/kg), and high-dose (5 g/kg) LPP respectively, and the hormone group treated by pregnant mare gonadotrophin serum and chorionic gonadotrophin (PMSG/hCG). The estrous cycle was determined by daily observation of vaginal smears; serum estradiol and testosterone were estimated by enzyme-linked immunosorbent assay; ovarian morphology, ovary volume and fertility of female rats were all detected during the study.
During 21 days of LPP treatment, about 20%increase of rats with regular estrous cycle of 4-6 days was found, but no change was detected on serum estradiol and testosterone at the dose of 1.67 g/kg and 5 g/kg LPP. Both ovary index and uterus index were up-regulated significantly at the dose of 5 g/kg LPP, but no regulation on oviduct index, adrenal gland index, pancreatic gland index and spleen index was observed at the two LPP groups. 5 g/kg LPP increased total number of pregnant mothers and the offspring; however there are no offspring in PMSG/hCG group. The offspring exhibited similar body weight in each treatment, and no apparent malformation was found for the cubs. While PMSG/hCG treatment increased the ovary index, serum estradiol and testosterone concentration considerably, but no improvement was found on estrous cycle, oviduct index, uterus index, and reproduction.
Administration of LPP may have comparable benefits for ovarian dysfunction, but with fewer side effects. Oral LPP have a better overall influence on rats than PSMG/hCG; it may be more effective in improvement of estrous cycle, ovary function and reproduction.