Proliferation of the superficial epithelium of ovaries in senile female rats following oral administration of conjugated equine estrogens.
OBJECTIVE
To evaluate the effect of different concentrations of estrogen on the ovarian superficial epithelium in senile female rats.


METHODS
Fifty female rats at 15 months of age and with irregular estrous cycles were selected and randomly divided into five experimental groups containing equal numbers of animals in each: GPROP, control group receiving vehicle only; GE0.05mg, group receiving conjugated equine estrogens (CEE) at a dose of 50 microg/kg; GE0.5mg, group receiving CEE at 500 microg/kg; GE1mg, group receiving CEE at 1 mg/kg; and GE2mg, receiving CEE at 2 mg/kg. The length of treatment was 21 days. After this period, the animals were anesthetized and the ovaries were fixed in 10% formaldehyde and processed for routine histology. Histomorphology was analyzed by light microscopy, and histomorphometrics were evaluated using the Imagelab program.


RESULTS
In the GPROP and GE0.05mg groups, the superficial epithelium of the ovary had a simple cuboidal shape, and as the estrogen dose increased, the epithelium thickened, with pseudo-stratified or stratified epithelium appearing in the GE2mg group. The animals in the group given the highest estrogen dose (GE2mg) showed the thickest ovarian epithelium and the largest perimeter and surface area of the surface ovarian epithelium (P < 0.01). However, the difference in epithelium thickness between the GE0.5mg and GE1mg groups was only slight.


CONCLUSIONS
Our data suggest that CEE at a dose of 2 mg/kg may induce marked proliferation of rat ovarian epithelium.
Perniconi
Sergio Eduardo
SE
Morphology Department, UNIFESP, São Paulo, SP, Brazil.
Simões
Manuel de Jesus
Mde J
Simões
Ricardo Dos Santos
Rdos S
Haidar
Mauro Abi
MA
Baracat
Edmund C
EC
Soares
Jose Maria
JM
D000284:Administration, Oral; D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects; D004195:Disease Models, Animal; D004353:Drug Evaluation, Preclinical; D004848:Epithelium / Q000187:drug effects / Q000473:pathology; D015914:Estrogen Replacement Therapy; D004967:Estrogens / Q000009:adverse effects* / Q000627:therapeutic use; D004966:Estrogens, Conjugated (USP) / Q000009:adverse effects* / Q000627:therapeutic use; D030762:Estrous Cycle / Q000187:drug effects; D005260:Female; D010051:Ovarian Neoplasms / Q000139:chemically induced; D010053:Ovary / Q000187:drug effects* / Q000473:pathology; D011230:Precancerous Conditions / Q000139:chemically induced; D011897:Random Allocation; D051381:Rats
D004967:Estrogens; D004966:Estrogens, Conjugated (USP)