Escherichia coli inhibits endometriosis by inducing M1 polarity of peritoneal macrophages and the IL-1 signaling pathway.

The development of endometriosis is closely linked to macrophages, and the type M1 macrophage has been hypothesized to play an inhibitory role in its progression. Escherichia coli induces macrophage polarization toward M1 in numerous diseases and differs in the reproductive tract of patients with and without endometriosis; however, its specific role in endometriosis development remains unknown. Therefore, in this study, E. coli was selected as a stimulator to induce macrophages, and its effects on the growth of endometriosis lesions in vitro and in vivo were investigated using C57BL/6N female mice and endometrial cells. It was revealed that E. coli inhibited the migration and proliferation of co-cultured endometrial cells by IL-1 in vitro and prevented the growth of lesions and induced macrophage polarization toward M1 in vivo. However, this change was counteracted by C-C motif chemokine receptor 2 inhibitors, suggesting that it was associated with bone marrow-derived macrophages. Overall, the presence of E. coli in the abdominal cavity may be a protective factor for endometriosis.