Regression of endometrial explants in rats treated with the cyclooxygenase-2 inhibitor rofecoxib

To investigate the effects of cyclooxygenase-2 (COX-2) inhibitor rofecoxib on endometrial explants and on peritoneal vascular endothelial growth factor (VEGF) levels in the rat endometriosis model.

Prospective, placebo-controlled study.

Laboratory at Dokuz Eylül University.

Twenty-six rats with experimentally induced endometriosis.

Rats were treated for 3 weeks with oral rofecoxib (3 mg/kg per day; n = 9); single subcutaneous injection of depot leuprolide acetate (1 mg/kg; n = 9); or vehicle (control; n = 8).

Change in explant area and histologic examination by semiquantitative analysis of endometriotic explants and measurement of peritoneal VEGF levels.

Three weeks of treatment with rofecoxib statistically significantly decreased the implant size (62.4%) compared with control (16.6%), and this effect was comparable with the decrease in leuprolide (64.3%). Histologic examination of the explants indicated mostly atrophy and regression in treatment groups, and semiquantitative analysis showed statistically significantly lower scores in rats treated with rofecoxib and leuprolide compared with controls. Both rofecoxib and leuprolide statistically significantly decreased VEGF levels compared with controls.

Rofecoxib causes regression and atrophy of the endometriotic lesions and is as effective as a GnRH agonist with an accompanying decrease in the VEGF levels.