title: The effects of letrozole and melatonin on surgically induced endometriosis in a rat model: a preliminary study.
abstract: 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.
authors.affiliation: Center for Reproductive Medicine, Department of Obstetrics, and Gynecology, Yeditepe University Hospital, Istanbul, Turkey. gaziyildirim@gmail.com
authors.forename: Gazi
authors.initials: G
authors.lastname: Yildirim
authors.forename: Rukset
authors.initials: R
authors.lastname: Attar
authors.forename: Ferda
authors.initials: F
authors.lastname: Ozkan
authors.forename: Banu
authors.initials: B
authors.lastname: Kumbak
authors.forename: Cem
authors.initials: C
authors.lastname: Ficicioglu
authors.forename: Narter
authors.initials: N
authors.lastname: Yesildaglar
mesh_terms: 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
chemical_list: D000970:Antineoplastic Agents; D000975:Antioxidants; D009570:Nitriles; D014230:Triazoles; D000077289:Letrozole; D008550:Melatonin