The Estrogenic Activity Of Formononetin And Its Effects On The Expression Of Estrogen Receptor In Aortic Arch Of Ovariectomized Rats

Objective To investigate the estrogenic activity of Formononetin and its effects on the expression of Estrogen Receptor in aortic arch of ovariectomized ratsMethods: 50 femal rats were divided in five groups randomly:the sham group,model group, niestriol group,formononetin groups of low dose and high dose.The rats in sham group were cut a piece of fat before closing the abdomen,the others were ovariectomized.Take the vaginal cell smear form the fifth day to the tenth afeter operation.rats were fed with high fat diet after anmimal models were confirmed successful.In the mean time,The sham and model groups were given nomal saline in 1ml.100g^-1.d^-1 by gavage,the other three groups were given nilestriol 2.5 mg.kg^-1.w^-1,low(20 mg.kg^-1.d^-1 )and high dose(100 mg.kg^-1.d^-1) of formononetin by gavage respectively.In the 8th week,take the vaginal cell smear,then decapitate the rats,take the uterine,weighed and fix it, stain and microscopy.Western blot and real time PCR were used to detect the expression of estrogen receptorα,βin aortic arch of these rats.Results 1.Vaginal exfoliated cells of the sham group showed normal estrous cycle,uterus index of 1.3547±0.2014;model group,vaginal exfoliated cells continued to show a large number of multi-core white blood cells , uterine index reduced severely (0.2609±0.0472) ,endometrial serious decline;nilestriol group continued for a large number of vaginal exfoliated cells of keratinized epithelial cells,uterine index of 1.097±0.2461 , significant epithelial hyperplasia ; high-dose formononetin group vaginal exfoliated cells continued to keratinized epithelial cells,uterine index 0.7107±0.0521 compared with model group , there was significant difference (P <0.05) , endometrial morphology similar to the sham group;low dose group,shedding a large number of multi-core white blood cells,uterine index of 0.3962±0.0424,compared with model group,no significant difference ( P> 0.05),endometrial atrophy.2.On protein level,the model rats ERβcontent of the aortic arch compared with the sham group was significantly reduced (0.5531±0.0457Vs0.8188±0.0719,P <0.05),nilestriol group and high dose formononetin group are higher than model group (0.8883±0.0904,7264±0.0659,P <0.05),low-dose formononetin group (0.5760±0.0369) increased litter to the model group,but no significant difference between the two (P > 0.05).3.On gene level,the content of ERαmRNA and ERβmRNA in model group were 37.6% -48% and 43% -55% respectively versus to the sham group;ERαmRNA expression in nylestriol group were 204% -262% versus to the model group,and the expression in low and high dose formononetin group were 90% -115 and 96% -121% respectively;ERβmRNA expression in nylestriol group and the high dose formononetin group were 196% -244% and 151% -184% respectively versus to the model group,but the expression in low dose formononetin group were 93% -119% only.Conclusion:Formononetin have weak estrogen-like effect on sexual organs and can selectively upregulated the expression of vascular ERβon ovariectomized rats.