The effects of letrozole and melatonin on surgically induced endometriosis in a rat model: a preliminary study.
Fertility and sterility 2009 Oct 28; In press
Yildirim G, Attar R, Ozkan F, Kumbak B, Ficicioglu C, Yesildaglar N
Center for Reproductive Medicine, Department of Obstetrics, and Gynecology, Yeditepe University Hospital, Istanbul, Turkey.
OBJECTIVE: To determine the effects of letrozole and melatonin on surgically induced endometriosis in a rat endometriosis model. DESIGN: Prospective, randomized, controlled, experimental study. SETTING: Experimental Research Center of Yeditepe University (YUDETAM). ANIMAL(S): Thirty female, nonpregnant, nulligravid Wistar-Hannover albino rats. INTERVENTION(S): Surgical induction of endometriosis, administration of estrogen for 2 weeks, and laparotomy; administration of letrozole or melatonin for 2 weeks after induction of endometriosis, and laparotomy; administration of estrogen for 2 weeks and necropsy. MAIN OUTCOME MEASURE(S): The volume and histopathologic scores of endometriotic foci, and levels of superoxide dismutase, catalase, and malondialdehyde in the peritoneal fluid. RESULT(S): The mean volumes of the endometriotic foci were 99.6 +/- 18.8 mm(3), 21.5 +/- 7.4 mm(3), and 29.2 +/- 17.5 mm(3), and histopathologic scores were 2.5 +/- 0.7, 2.0 +/- 0.8, and 1.7 +/- 0.9 in the melatonin group at the end of the second, fourth, and sixth weeks, respectively. The mean volumes of the endometriotic foci were 75.9 +/- 26.3 mm(3), 29.8 +/- 14.7 mm(3), and 121.2 +/- 35.1 mm(3) and the histopathologic scores were 2.5 +/- 0.5, 2.2 +/- 0.8, and 2.7 +/- 0.4 in the letrozole group at the end of the second, fourth, and sixth weeks, respectively. In the melatonin group, peritoneal fluid superoxide dismutase and catalase levels increased statistically significantly. CONCLUSION(S): Melatonin caused more pronounced regression of endometriotic foci when compared with letrozole in a rat model. After the cessation of melatonin treatment, the recurrence rate was lower than that observed after the cessation of letrozole treatment.
Keywords: letrozole melatonin endometriosis