Transmission and scanning electron microscopic examination of rat vaginal epithelium in the normal estrous cycle and in persistent estrous

Abstract

AbstractThe rat vaginal epithelium in both normal and persistent estrous (PE) cycles was examined by transmission and scanning electron microscopy utilizing cardiac perfusion and ruthenium red staining. It was demonstrated that surface vaginal epithelium in persistent estrous exhibited irregularly shaped cells. Borders were not well defined as is the case in normal estrous, and cells lacked the complex, interconnecting microridges and pits. Vaginal surfaces were completely smooth or covered with few microvilli. In the control specimens the fine structure en block stained with ruthenium red showed distinct cell membranes bordering the intercellular spaces between epithelial cells. With PE rats, this finding was absent, and there was instead a significant expansion of intercellular space with villiform processes of the cytoplasm projecting into the space. Utilization of the combination of techniques described provided the investigators with a better definition of vaginal tissue ultrastructure and revealed significant morphological differences between the normal estrous cycle and persistent estrous in vaginal specimens from rat models.