Intraperitoneal administration of activin A promotes development of endometriotic lesions in a mouse model of endometriosis.

Purpose: This study aimed to investigate the effect of intraperitoneal administration of activin on the occurrence of endometriosis using a mouse model of endometriosis.
Methods: A mouse model of endometriosis was prepared by intraperitoneally administering endometrial tissue and blood collected from donor mice to C57BL/6J 7-8- week-old recipient mice. A total of 400 μg of activin A was intraperitoneally administered to model mice in the activin group for 5 days. Intraperitoneal endometriotic lesions were confirmed macroscopically and IL-6 and TNF-α levels in washed ascites were measured by ELISA.
Results: Endometriotic lesions were observed in all mice. In the activin group, the maximum diameter of endometriotic lesions was significantly larger than that in control group (4.7?1.3 vs 2.9?0.9 mm, p?0.01). The total area of the lesion was also significantly higher in the activin group than in the control group (21.1?9.9 vs 8.8?5.4 mm ² ,p?0.01). Furthermore, IL-6 and TNF-α levels in ascites were significantly higher in the activin group than in the control group (IL-6 : 85.8?15.3 vs 75.1?19.3 pg/ml, p?0.05 ; TNF-α : 629.8?15.4 vs 605.9?11.4 pg/ml, p?0.05).
Conclusion: Activin promotes occurrence of endometriosis. Inflammatory cytokines are also elevated by activin administration,suggesting that they may contribute to progression of endometriosis J. Med. Invest. 66 : 123-127, February, 2019.