Non-thermal plasma prevents progression of endometriosis in mice

Endometriosis is observed in ∼10% of reproductive age women. Ovarian endometriosis not only causes dysmenorrhea but also causes infertility and a high risk of adenocarcinoma. Due to its scattered nature, complete surgical resection is difficult. Endometriosis consists of glandular and stromal cells. Previously, we showed that endometrial stromal cells (ESCs) play a role in the protection against pathologic events caused by monthly repeated hemorrhage. Here, we undertook a preclinical study of non-thermal plasma (NTP) as a surgical treatment of endometriosis. Epithelial cells were most sensitive to NTP-activated medium in vitro, whereas ectopic ESCs were most resistant. We then transplanted excised uteruses into BALB/c mice from donors of the same strain with estradiol supplementation. Four weeks after the transplantation, we exposed NTP to each endometriotic lesion after laparotomy. Immunohistochemical analysis revealed that immediately after NTP exposure, epithelial cells exhibited significantly higher levels of nuclear immunostaining for 8-hydroxy-2'-deoxyguanosine than did stromal cells. Four weeks after NTP exposure, the total surface area consisting of endometriotic cysts was significantly smaller with less epithelial proliferative activity than the helium-exposed control, whereas the number of endometriotic lesions had not changed. Therefore, NTP exposure may be useful to prevent the progression and recurrence of endometriosis.