Effects of melatonin on histomorphology and on the expression of steroid receptors, VEGF, and PCNA in ovaries of pinealectomized female rats.
OBJECTIVE
To evaluate the effect of melatonin both on the ovaries of pinealectomized female rats through histomorphometric analysis and on steroid receptors, proliferating cell nuclear antigen (PCNA), and vascular endothelial growth factor (VEGF) expression.


METHODS
Experimental study.


METHODS
Federal University of São Paulo, Brazil.


METHODS
Forty female rats.


METHODS
Forty rats were divided equally into four groups: GI-vehicle without surgery; GII--surgery without removal of the pineal gland (sham); GIII--pinealectomized with vehicle; and GIV--pinealectomized with melatonin treatment. After treatment for 3 consecutive months, the animals were killed and their ovaries removed for analysis.


METHODS
Estrogen and progesterone receptors, histologic and immunohistochemical analysis.


RESULTS
The GIII samples presented signals of proliferation on ovarian surface epithelium and interstitial cells as well as high expressions of PCNA and VEGF in those structures compared with GI, GII, and GIV. Also, the levels of progesterone receptor (fmol/g) in ovaries of GIII (250.6 ± 32.4) were significantly lower than in those of GI (429.0 ± 23,8), GII (442.3 ± 30.2), and GIV (564.1 ± 78.7). The levels of progesterone in GIII were superior to those in GI, GII, and GIV.


CONCLUSIONS
Our findings suggest that melatonin may attenuate proliferation in ovarian structures and increase the number of luteal bodies as well as the levels of progesterone receptor.
Romeu
Lucrecia Regina G
LR
Gynecology Department, Federal University of São Paulo, São Paulo, Brazil.
da Motta
Eduardo Leme A
EL
Maganhin
Carla C
CC
Oshima
Celina T F
CT
Fonseca
Marcelle C
MC
Barrueco
Karina F
KF
Simões
Ricardo S
RS
Pellegrino
Renata
R
Baracat
Edmund C
EC
Soares-Junior
José M
JM
D000818:Animals; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation; D008550:Melatonin / Q000502:physiology*; D010053:Ovary / Q000166:cytology / Q000378:metabolism*; D010870:Pineal Gland / Q000378:metabolism / Q000601:surgery*; D018809:Proliferating Cell Nuclear Antigen / Q000096:biosynthesis*; D011485:Protein Binding / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D011987:Receptors, Steroid / Q000096:biosynthesis* / Q000235:genetics; D015398:Signal Transduction / Q000235:genetics; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis* / Q000235:genetics
D018809:Proliferating Cell Nuclear Antigen; D011987:Receptors, Steroid; D042461:Vascular Endothelial Growth Factor A; D008550:Melatonin