Type VI collagen expression during growth of human ovarian follicles

Objective: To identify type VI collagen expression in human ovarian follicl es during follicular growth. Design: In vitro experiment. Setting: Department of Obstetrics and Gynecology, Wakayama Medical College, Japan. Patient(s): Regularly cycling women who underwent adnexectomy. Intervention(s): Immunohistochemistry and in situ hybridization for human t ype VI collagen. Main Outcome Measure(s): Expression of type VI collagen. Result(s): Expression of type VI collagen was observed in the theca cell la yers during folliculogenesis, whereas no expression of type VI collagen was observed in the granulosa cell layers at the mRNA and protein levels. As t he follicles grew, immunostaining for type VI collagen became intense in th e theca cell layers, especially the theca externa. In preovulatory follicle s, however, weak, fragmented, or discontinuous immunostaining of the theca cell layers was observed. This fragmented or discontinuous immunostaining w as evident predominantly in the apical area of preovulatory follicles rathe r than in the basal area. Conclusion(s): Type VI collagen is present in the theca cell layers of foll icles during folliculogenesis and plays an important role in interactions b etween the theca cells and extracellular matrix. These interactions may lea d to changes in the shape, proliferation, migration, or differentiation of follicular cells during follicular development, maturation, and ovulation. (C)2000 by American Society for Reproductive Medicine.