The Effect Of Letrozole On The Endometrial Receptivity,Reproductive Capacity And Teratogenicity In SD Rats

[Objective]:To study the effects of letrozole on ovulation induction and teratogenicity in SD rats.[Method]: Fifty-eight SD rats were randomly divided into negative control group,solvent control group and letrozole(0.26,0.52,0.78 mg/kg )groups. The rats were administrated with corresponding reagents on proestrus and were placed together next night. Detection of sperm in the vaginal smear (taken as evidence of mating) at the end of the dark cycle (8:00 am) was used to designate gestation day 0. The pregnancy rats were dissected at 20th day after pregnancy.The corepus luteums,plant glands,absorbed fetuses,live fetuses,dead fetuses,body weights and body lengths were measured. The fetuses from each uterus were selected alternately either for skeletal examination or for visceral examination.[Results]:1.CMC didn't affect the results of experiment.2.Letrozole groups can induce ovulation in rats,but it can cause abortion in some rats.The live fetuses, plant glands on letrozole groups were less than that in control groups.The pre-plant dead rate and post-plant dead rate on letrozole groups were higher than that in the control groups.3.Letrozole has no teratogenic effect in fetuses at the dose of 0.26,0.52mg/kg, but it may cause visceral teratogenicity on some of live fetuses at the dose of 0.78mg/kg.[Conclusion]:Letrozole could induce ovulation in rats and increase the pre-implantation loss and post-implantation loss of fetuses.It may increase the visceral teratogenicity ratio of fetuses at the dose of 0.78mg/kg. [Objective]: To study the effects of letrozole in different doses and clomiphene citrate(CC) on the expression of pinpode,integrinαvβ3 and osteopontin in SD rats and study the reason of higher pre-plant dead ratio and post-plant dead ratio in letrozole groups on the last experiment.[Method]: Fifty SD rats were randomly divided into negative control group , CC group and letrozole(0.26,0.52,0.78 mg/kg )groups. The rats were administrated with corresponding reagents on proestrus and were placed together next night. Detection of sperm in the vaginal smear (taken as evidence of mating) at the end of the dark cycle (8:00 am) was used to designate gestation day 0. The pregnancy rats were dissected at 4th day after pregnancy.Endometrium of the rat was gained to observe pinpodes change by electron microscopy and to detect the expression of integrinαvβ3 and OPN by immunohistochemistry techiques.[Results]:1.The development of pinpodes on rat endometrium in 0.26,0.52 mg/kgLE groups were similar to that in the control group,which were fully developed and abundantly expressed. But the pinpodes in 0.78 mg/kg LE and CC groups were regressed, with increased elevatio,shrinked volume and emerged microvillus on the surface.2.The expression of integrinαvβ3 and OPN on rat endometrium in 0.26,0.52 mg/kgLE groups were similar to that in control group.However,their expression in 0.78 mg/kgLE and CCgroup were significantly poorer than that in the former three groups.[Conclusion]:Compared with 0.78 mg/kgLE and CCgroup, 0.26,0.52 mg/kgLE has no effect on pinpode formation and integrinαvβ3﹠OPN expression on rat endometrium during implantation period.However,endometrial receptivity is taken on rejection capability in degree in 0.78 mg/kgLE and CCgroup.