Effect of continuous light on reproductive rhythm of rats and intervention effect of Traditional Chinese Medicine / 医学研究生学报

ABSTRACT

Objective Light acts as an important zeitgeber and regulates the body's circadian rhythm.Excessive lighting at night leads to light pollution,which interferes with the circadian rhythm and thus adversely affects the body.To observe the adverse effect of continuous light on female reproductive endocrinology and explore effective treatment,the animal experiment was carried out.Methods 185 sexual maturity female SD rats in the age of 2 months with normal estrous cycle were enrolled.60 rats were selected randomly and enrolled into control group.Normal illumination conditions were given.The remaining rats were given 300±20lux light intensity for 24h/d last for 50 days to get reproductive rhythm disorder model.The model rats (100) were randomly divided into models group (n =50) and Traditional Chinese Medicine (TCM) group (n =50).Traditional Chinese Medicine group was treated with sequential TCM.At last we get 50 rats enrolled into model group and herbal group respectively.The TCM group rats were given therapy of nourishing yin and tonifying yang sequential TCM,while the two other groups were gavaged the same volume of physiological saline.The estrous cycle was observed in all groups.20 days later,blood were collected dynamically and E2 (estradiol),P (progesterone),LH (Luteinizing Hormone),FSH (Follicle-Stimulating Hormone)and melatonin were compared to evaluate the therapeutic effect of TCM.Finally,try to explain the mechanism of TCM's effect from the perspective of melatonin.Results At the first day,E2 was lower in TCM group and models group than control group (P＜ 0.05).At the second day,E2 was higher in traditional Chinese Medicine group than control group (9＜0.05).At the third day,E2 was higher in TCM group and models group than that in control group (P＜ 0.05).Progesterone in control group showed low level in pre-estrous and estrous period and elevated in the late stage of estrous.Progesterone showed no obvious change during the estrous cycle in TCM group and models group.At the third and fourth day,Progesterone was significantly lower in models group than TCM group and control group.At the first day,LH in models group [(249.8±50.2)mIU/mL] and TCM group [(83.4±37.3)mIU/mL] were significantly lower than control group [(430.0± 100.4)mIU/mL] (P＜0.05).At the first day,FSH in models group and TCM group were significantly lower than control group (P＜0.05).At the fourth day,FSH in TCM group was significantly lower than control group and models group (P＜0.05).Compared the melatonin among three groups,the circadian rhythm was high at night but low in the day in control group.The highest level was nearly 5 times higher than the lowest level.Neither the models group nor the TCM group had obvious recent rhythm changes.Conclusion Continuous light can induce disordered estrous cycle and loss of rhythm.Traditional Chinese Medicine can somehow induce circulation reconstruction.Continuous light can induce disordered endocrine,E2,FSH,LH surge abnormal,ovulation failure,luteal phase defect.TCM can induce ovulation and luteal support.Continuous light can destroy melatonin circadian rhythm and TCM can increase melatonin,which could be the mechanism of TCM's effect.