Abstract: Objective To analyze the relationship between the JAK2 / STAT3 signal transduction pathway and endometriosis (EMS). Methods Sixty rats were randomly divided into Sham-operated group, model group and JAK2 / STAT3 pathway inhibitor group (AG group). There were 20 rats in each group. In model group and AG group, EMS model was established by endometrial transplantation. The rats in AG group were given AG490 1 mg/kg 5 min before modeling, and AG490 4 mg/kg after surgery, 2 times a week for 4 weeks. The model group was given same volume of normal saline. After treatment, the volume of ectopic endometrium was recorded, the growth inhibition rate of ectopic endometrium was calculated, and the histopathological changes were observed by HE staining. The protein expression levels of p-JAK2, JAK2, p-STAT3 and STAT3 were detected by Western blot assay. Results After treatment, the volume of ectopic endometrium was significantly smaller in AG group than that in model group, and the inhibition rate of ectopic endometrial growth was 65.66%. The results of Western blot assay showed that JAK2 and STAT3 proteins and their phosphorylation levels (p-JAK2/ JAK2 and p-STAT3 / STAT3) were significantly increased in ectopic lesions of EMS rats compared with those in normal uterus. The expression levels of p-JAK2, p-STAT3, JAK2 and STAT3 were significantly decreased in ectopic lesions of AG group rats compared with those in EMS rats. Conclusion The JAK2/STAT3 pathway may play an important role in the pathogenesis of EMS, and the inhibition of JAK2/STAT3 signaling pathway can play a positive role in the treatment of EMS.

Key words: endometriosis, Janus kinase 2, STAT3 transcription factor, signal transduction, AG490