Abstract: Objective：To investigate the effect of Irisin on the endometrial function in obese rats. Methods：Female SD rats were treated with high-fat diets to induce obesity, while the normal-control group (n=16) was treated with normal diets. The obese rats were randomly divided into the model-control group (n=16) and the irisin group (n=16). The rats in the irisin group were injected intraperitoneally with recombinant irisin [100 ng/（g·d）×14 days], while the rats in the two control groups were injected with normal saline. Then, female rats in estrus were mated with male rats. Eight rats were sacrificed in each group on the day 5 and day 10 of pregnancy. The pregnancy rate, average number of blastocyst and embryo morphology were observed. The expressions of leukemia inhibitory factor (LIF) and integrin αvβ3 in the implantation sites were determined. Results：The body weight in the irisin group after treatment was significantly lower than that in the model-control group (P=0.035), and the average number of blastocyst in the model-control group were significantly lower than that in the irisin group and the normal-control group (both P＜0.05). The endometrium of the normal-control group was full, and the embryo was well developed. The uterine cavity in the model-control group was large, and the embryonic development was poor. The endometrium of the irisin group was closed, and the embryonic development was well improved. The expression levels of LIF and integrin αvβ3 mRNAs and proteins in the model-control group were significantly lower than those in the normal-control group and the irisin group (all P＜0.05). Conclusions：Irisin can improve the endometrial receptivity of obese rats by increasing the expressions of LIF and integrin αvβ3 in endometrium.

Key words: Obesity, Rats, Animal experimentatio, Endometrium, Leukemia inhibitory facto, Integrin alphaV, Integrin beta3, Irisin