Objective: The objective was to assess the effectiveness of the newly developed immunomodulator RESAN in the prophylaxis and treatment of endometriosis induced in rats.
Study design: The study was performed on 58 Wistar rats. Twelve weeks before endometriosis induction, the RESAN vaccine was administered to 24 rats (100 mg i.m. and 100 mg s.c.). Endometriosis induction was performed in 48 rats, which were divided into two groups: group I, the prophylaxis group, consisting of 24 previously vaccinated rats; and group II, the treatment group, comprising the other 24 rats, which had not been vaccinated. The graft (4 mm x 4 mm) of endometrium was attached to the parietal peritoneum. A sham operation was performed in 10 rats (group III). After 3 months, a second laparotomy was performed in all animals, and endometriotic foci were excised when present. RESAN was administered to the group II animals. After an additional 3 months, a third laparotomy was performed in all animals of the three groups.
Results: Positive, histologically confirmed endometriosis was found in 4.3% of the animals in group I and in 69.6% of group II rats (p<0.0001). Macroscopic assessment revealed endometriosis in 21.7% and 91.3% of animals in groups I and II, respectively (p<0.0001). At final laparotomy, 3 months after excision of the previously suspected foci, no signs of endometriosis were found according to both macroscopic assessment and histological examination. During the second laparotomy intraperitoneal adhesions were present in 13.0% of the animals in group I and in 61.0% of those in group II. No adhesions were present in group III. At the final laparotomy, the adhesions were present in only three of the animals in group II (p<0.0009).
Conclusions: RESAN seems to be effective in both the prophylaxis and treatment of endometriosis, as well as in the prophylaxis of adhesions. Histological confirmation of endometriosis should be mandatory.