ABSTRACT
Estrous cycle -related histological and histochemical changes in the vaginal epithelium of mature female rats were studied with PAS (periodic acid Schiff) alcian blue pH 2.5 and biotinylated lectins (DBA, SBA, PNA, BSL -1, sWGA, UEA -1, RCA -1, Con A and LCA).The prominent characteristic changes that occured during the estrous cycle were mucinous transformation in proestrus and cornification in estrus. In proestrus, the superficial mucinous cells of the epithelium were increased in number and enlarged in size, and the amount of acid and neutral mucosubstances was more increase in proestrus than in diestrus and metestrus. About the binding pattern of all lectins examined to the superficial mucinous cells, in diestrus, the binding pattern of these cells showed a similar affinity as in metestrus with intense DBA and UEA -1 reactivity. In proestrus, however, these cells were reactive with seven lectins examined except LCA and PNA, and DBA, SBA, BSL -1, RCA -1 and UEA -1 reacted more strongly than in diestrus and metestrus. In estrus, the superficial cornified cell layers showed a weak reactivity of SBA, BSL -1 and PNA. In diestrus and metestrus, the mucinous cells in the intermediate layers of the basal portion of vaginal fold stained with eight lectins examined except LCA and showed the same binding pattern to the superficial mucinous cells. About the distribution of glycoconjugates in the intermediate layer, the upper spindle cells showed different binding pattern according to the estrous stages. In diestrus, estrus, and metestrus, these cells showed a affinity for all lectins examined. In proestrus, however, DBA and PNA staining were not observed, and stained more intensely with sWGA, SBA and UEA -1, and less intensely with BSL -1 and RCA - 1. In estrus, DBA and PNA reactivity reappeared as trace, and RCA -1 and sWGA reactivity increased. In metestrus, sWGA reactivity reduced and BSL -1 and UEA -1 increased continually. The lower rounded cells of the intermediate layers stained with all lectins examined in estrus, with six lectins examined except Con A, DBA and UEA -1 in proestrus and with five lectins examined except DBA, UEA -1, sWGA and BSL -1 in diestrus and metestrus. BSL -1 reactivity for the layers increased in proestrus, estrus and metestrus, and PNA reactivity increased in estrus and reduced in metestrus. The basal layer of the vaginal epithelium showed different binding pattern to the different portion of vagina, and showed faint staining of BSL -1, SBA and RCA -1, and moderately staining of BSL -1 in proestrus and estrus. In conclusion, alpha /-N -acetyl -D -galactosamine, alpha /-D -galactose and alpha -L -fucose participate in the mucinous transformation of the vaginal epithelium, and beta -N -acetyl -D -glucosamine participates in the cornification of the vaginal epithelium.