<Original Article>lmmunohistochemical localization of tenascin and ki-67 nuclear antigen in human endometrium throughout the normal menstrual cycle

Abstract

To elucidate the possible regulation of endome­trial growth, we investigated the expression of tenascin, an extracellular matrix protein associated with cell proliferation and morphogenetic events, in relation to the mitotic marker ki-67 antigen in human endometrium throughout the menstrual cycle. The endometrial tissue was obtained from women with regular menstruation undergoing hysterectomy due to benign uterine disease. Cryostat sections were subjected to double immunohistochemistry to detect both tenascin and ki-67. During the proliferative phase, an intense deposition of tenascin fibrils occurred in the extracellular matrix of the stroma immediately subjacent to the uterine epithelium that showed the highest proportion of ki-67 positive cells. In the secretory phase, the amount of tenascin expres­sion and the proliferative index of the epithelium were markedly reduced. The topological immunoreactivity of tenascin, however, was clearly related to ki-67 localization close to the tortuous endometrial gland and spiral artery. Expression of tenascin, showing changes depending on the menstrual phase, appears to be influenced by ovarian steroid hormones, and it might play a role in regulating human endometrial development by interaction with mitotic cells.