Effects of melatonin on the endometrial morphology and embryo implantation in rats.
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.
Dair
Elisabete Lílian
EL
Department of Gynecology, Federal University of São Paulo, São Paulo, Brazil.
Simoes
Ricardo Santos
RS
Simões
Manuel Jesus
MJ
Romeu
Lucrecia Regina Gomes
LR
Oliveira-Filho
Ricardo Martins
RM
Haidar
Mauro Abi
MA
Baracat
Edmund C
EC
Soares
José Maria
JM
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
C054513:6-sulfatoxymelatonin; D011374:Progesterone; D004958:Estradiol; D008550:Melatonin