Decreased Endometrial IL-10 Impairs Endometrial Receptivity by Downregulating HOXA10 Expression in Women with Adenomyosis

OBJECTIVE: The aim of this study was to investigate the potential role of IL-10 in regulating the receptivity marker HOXA10 in the endometrium of women with adenomyosis. METHODS: The expression levels of IL-10, HOXA-10, STAT3, and p-STAT3 in the endometrium of women with adenomyosis and controls were examined by means of western blotting and immunohistochemistry. The expression of the HOXA10 protein in Ishikawa cells treated with rIL-10 was examined by western blotting. The attachment rate of BeWo cell spheroids to Ishikawa cells treated with rIL-10 was expressed as a percentage of the total number of spheroids. RESULTS: The expression levels of HOXA10 and IL-10 in the adenomyosis group were significantly lower than those in the control group, and there was a positive correlation between HOXA10 and IL-10 protein levels in all the women examined. rIL-10 increased HOXA10 expression in a concentration- and time-dependent manner by inducing the phosphorylation of STAT3 in Ishikawa cells. Treatment with rIL-10 promoted the attachment of BeWo spheroids to Ishikawa cells, which was reversed by the inhibition of STAT3 phosphorylation. The expression of p-STAT3 in the adenomyosis group was significantly lower than that in the control group, and there was a positive correlation between IL-10 and p-STAT3 protein levels in all the women examined. CONCLUSIONS: Both IL-10 and HOXA10 levels in the endometrium are significantly reduced in women with adenomyosis compared with those in control women. The phosphorylation of STAT3 has been proven to be a critical mediator between IL-10 and HOXA10, which may play critical roles in embryo implantation.