A HISTOLOGICAL AND IMMUNOHISTOCHEMICAL STUDY ON THE EFFECT OF ESTROGEN ON URINARY BLADDER IN OVARIECTOMIZED ADULT FEMALE ALBINO RATS
Mary A. Morcos, Noha M. Afifi, *Samraa, H. Abd-El Kawi and*Mai A. Mohammed
Histology Department, Faculty of Medicine, Cairo and *Benisweif University
Introduction: Periods of marked changes in female hormone levels such as puberty, pregnancy and menopause induce significant alterations in the lower urinary tract. Decrease in circulating estrogen after menopause has been associated with many urinary bladder (UB) dysfunctions.Aim of the work: The study aimed at understanding the histological changes induced in the UB after estrogen deprivation using an experimental menopause model of ovariectomized (OVX) rat and the extent to which estrogen replacement therapy can correct such changes.Materials and Methods: Forty five adult female albino rats were divided into 3 groups. The first group (10 rats) included the control sham-operated rats. The second group (15 rats) was subjected to bilateral OVX. The third group (20 rats) was subjected to bilateral OVX and 2 weeks after OVX, received Ethinyl Estradiol in a dose of 0.8 mg/kg/day orally for 8 weeks (IIIa) and for 12 weeks (IIIb). Animals were sacrificed 10 and 14 weeks following the sham operation and OVX. UB specimens were removed and processed. Sections were subjected to the following stains: H&E, Masson's Trichrome, Estrogen receptor beta (ERβ) and Alpha smooth muscle actin (α-SMA) immunostaining. Digital image analysis was applied to determine: epithelial height, area percent of collagen fibers, area percent of ERβ and α-SMA immunostaining. Results were statistically compared.Results: Microscopic examination of UB sections of OVX rats revealed epithelial shedding and exfoliation with the presence of cytoplasmic vacuolation and pyknotic nuclei. Smooth muscle (SM) fascicles appeared widely separated. In group III, restoration of the lining transitional epithelium was demonstrated. SM bundles appeared compact. Collagen fiber (CF) content in the interfascicular spaces increased in group II and then showed highly significant decrease in group III. Area percent of ERβ and α-SMA immunoreactivity showed highly significant decrease in group II and then were markedly up-regulated in group III.Conclusion: OVX rat model of menopause presented marked changes in UB histology. Such changes were markedly improved by estrogen supplementation.