Electron microscopic determination of changes in the surface epithelium of the rat uterus during the estrous cycle.

VIII. SUMMARYIn this study, electron microcopic determination of changes in the surface epithelium ofthe rat uterus during the estrous cycle was examined.With this aim, 16 Sprague Dawley albino female rats were put in 4 different groupsaccording to their estrous cycles. The `estrous cycle? in female rats stages were proestrous,estrous, metaestrous and diestrous. Vaginal smears were obtained once a day and stained using anadaptation of the Papanicoalou (PAP) procedure. Suitable sections from rat uterus for light andelectron microscopic study were prepared. Half thick cross sections were painted with toluidinblue and examined with Olympus photo light microscope, thick cross section were taken frommarked areas and examined on microscope Carl Zeiss EM 900 and photographed.During proestrous in electron microscopic thick cross section, the cells haddistinguishable tight junctions in the side surface. Side surface tight junctions had interdigitations.Increase in length of epithelium, the indented lumen, the formation of pseudoglands, developedstructure of fibroblast-like stromal cells in lamina propria and the fulness in veins harmonized withdevelopment in early proliferation stage. During estrous cycle, behind the apical cells generallylike a dot were well developed. Also during this stage the interdigitations which were in the basalcytoplasm were more developed than the proestrous. In this stage, increase in length of epithelium, the presence of apoptotic cell and substances, formation of foldings in glandular lumens,developed resident stromal cells in lamina propria, increase in angiogenesis and collagen fibers,the presence of hypertrophic smooth muscle cells were proper findings for follicular phase (lateproliferate) of rat uterus in estrous cycle. Among the structural alteration in rat uterus inmetaestrous cycle, the distinctive decrease in epithelium length, the presence of highly developeduterus glands and pseudoglands, increase in developed resident stromal cells in lamina propria,smooth muscle cells with dense cytoplasm were all evaluated as convinient findings for earlysecretory phase. In diestrous stage, the alterations in metaestrous cycle increased and the findingswere harmonic with late secretory phase of human uterus.As a result, it was concluded that light and electron microscopic findings for rat estrouscycle consisting of proestrous, estrous, metaestrous and diestrous stages matched with humanproliferate, follicular and early-late secretory phase findings.