title: Effects of melatonin on the endometrial morphology and embryo implantation in rats.
abstract: OBJECTIVE
  To determine the effects of melatonin on rat endometrium morphology and embryo implantation.
  
  
  METHODS
  Experimental study.
  
  
  METHODS
  Federal University of São Paulo, Brazil.
  
  
  METHODS
  Forty female rats.
  
  
  METHODS
  GI: control, GII: sham-operated, GIII: pinealectomized, and GIV: pinealectomized rats that received melatonin during 3 months. The GI, GII, and GIII groups received the vehicle of melatonin (NaCl + ethanol). At the end of the treatment, the animals were killed during the estrous phase; the uterus was removed for morphometric analysis. Urine was collected for 6-sulfatoxymelatonin. Blood was collected for estrogen (E) and progesterone (P) level determinations. In a second experiment, female rats were used to evaluate the endometrial embryo implantation.
  
  
  METHODS
  Endometrial morphology and embryo implantation.
  
  
  RESULTS
  GIII presented the highest values for endometrial area and thickness index, number of endometrial glands, and eosinophils. The number of vessels of groups I, II, and IV was fewer than that of GIII. The highest number of eosinophils was detected in GIII in comparison to other groups. The implantation rate in GIII was the lowest of all groups. This implantation rate was significantly increased and restored toward normal in GIV.
  
  
  CONCLUSIONS
  Our data suggested that, in nonphotoperiodic animals such as rats, melatonin may positively affect the endometrial morphology and improve embryo implantation.
authors.affiliation: Department of Gynecology, Federal University of São Paulo, São Paulo, Brazil.
authors.forename: Elisabete Lílian
authors.initials: EL
authors.lastname: Dair
authors.forename: Ricardo Santos
authors.initials: RS
authors.lastname: Simoes
authors.forename: Manuel Jesus
authors.initials: MJ
authors.lastname: Simões
authors.forename: Lucrecia Regina Gomes
authors.initials: LR
authors.lastname: Romeu
authors.forename: Ricardo Martins
authors.initials: RM
authors.lastname: Oliveira-Filho
authors.forename: Mauro Abi
authors.initials: MA
authors.lastname: Haidar
authors.forename: Edmund C
authors.initials: EC
authors.lastname: Baracat
authors.forename: José Maria
authors.initials: JM
authors.lastname: Soares
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects; D010064:Embryo Implantation / Q000187:drug effects*; D004717:Endometrium / Q000166:cytology* / Q000187:drug effects*; D004958:Estradiol / Q000032:analysis / Q000097:blood; D005260:Female; D008297:Male; D008550:Melatonin / Q000031:analogs & derivatives / Q000032:analysis / Q000494:pharmacology* / Q000652:urine; D009929:Organ Size; D010870:Pineal Gland / Q000502:physiology / Q000601:surgery; D011247:Pregnancy; D011374:Progesterone / Q000032:analysis / Q000097:blood; D011555:Pseudopregnancy; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D014599:Uterus / Q000033:anatomy & histology / Q000187:drug effects
chemical_list: C054513:6-sulfatoxymelatonin; D011374:Progesterone; D004958:Estradiol; D008550:Melatonin