The Effect of Ulipristal Acetate on Surgical Endometriosis Created in Rats

Objective: The effect of Ulipristal Acetate on endometriosis foci created in rats was investigated. 
Methods: The study was conducted with 12-week-old rats weighing approximately 280 grams. After creating an autologous endometriosis model, the group that did not receive ulipristal acetate negative was administered with oral saline daily, and the group given ulipristal acetate positive was administered with 0.5 mg/kg (0.125 mg/rat/day) orally for 4 weeks. Ectopic endometrial tissues were removed for histopathological and immunohistochemical evaluations. Staining was performed with Hematoxylin Eosin, Ki-67, and Cyclooxygenase-2.
Results: The Hematoxylin-Eosin Staining score of the ectopic endometrium surface epithelium was found to be 2.5 points in the ulipristal acetate negative group, and 0.5 points in the ulipristal acetate positive group. In the immunohistochemical evaluation, Ki-67 positivity of the ectopic endometrial surface epithelium was found to be 71.2% in the ulipristal acetate negative group vs. 31.7% in the ulipristal acetate positive group. Cyclooxygenase-2 positivity was detected as 67% in the ulipristal acetate negative group vs. 27% in the ulipristal acetate positive group.
Conclusions: Hematoxylin-Eosin staining revealed that ulipristal acetate negative group was 2.5 (well-moderately preserved epithelium), and the ulipristal acetate positive group was 0.5 (epithelium was rarely present or absent). It was found that the percentage of Ki-67 and Cyclooxygenase-2 immunohistochemical positivity was decreased in the ulipristal acetate positive group compared to the ulipristal acetate negative group at a statistically significant level. More literature data are needed on this subject.