The effects of letrozole and melatonin on surgically induced endometriosis in a rat model: a preliminary study.
OBJECTIVE
To determine the effects of letrozole and melatonin on surgically induced endometriosis in a rat endometriosis model.


METHODS
Prospective, randomized, controlled, experimental study.


METHODS
Experimental Research Center of Yeditepe University (YUDETAM).


METHODS
Thirty female, nonpregnant, nulligravid Wistar-Hannover albino rats.


METHODS
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.


METHODS
The volume and histopathologic scores of endometriotic foci, and levels of superoxide dismutase, catalase, and malondialdehyde in the peritoneal fluid.


RESULTS
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.


CONCLUSIONS
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.
Yildirim
Gazi
G
Center for Reproductive Medicine, Department of Obstetrics, and Gynecology, Yeditepe University Hospital, Istanbul, Turkey. gaziyildirim@gmail.com
Attar
Rukset
R
Ozkan
Ferda
F
Kumbak
Banu
B
Ficicioglu
Cem
C
Yesildaglar
Narter
N
D000465:Algorithms; D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000494:pharmacology; D000975:Antioxidants / Q000008:administration & dosage / Q000494:pharmacology; D004353:Drug Evaluation, Preclinical; D004715:Endometriosis / Q000188:drug therapy* / Q000209:etiology / Q000473:pathology; D005260:Female; D013509:Gynecologic Surgical Procedures / Q000662:veterinary; D000077289:Letrozole; D008550:Melatonin / Q000008:administration & dosage / Q000494:pharmacology*; D009570:Nitriles / Q000008:administration & dosage / Q000494:pharmacology*; D010865:Pilot Projects; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D014230:Triazoles / Q000008:administration & dosage / Q000494:pharmacology*; D014591:Uterine Diseases / Q000188:drug therapy* / Q000209:etiology / Q000473:pathology
D000970:Antineoplastic Agents; D000975:Antioxidants; D009570:Nitriles; D014230:Triazoles; D000077289:Letrozole; D008550:Melatonin