EXTRACELLULAR-MATRIX PROTEINS AND BASEMENT-MEMBRANE - THEIR IDENTIFICATION IN BOVINE OVARIES AND SIGNIFICANCE FOR THE ATTACHMENT OF CULTURED PREANTRAL FOLLICLES

Described in the present paper is the immunolocalization of the extrac ellular matrix proteins (e.g., fibronectin, collagen Types I and III) in the bovine ovary, with special attention to preantral follicles. In addition, we have shown, histochemically and ultrastructurally, that mechanically isolated bovine preantral follicles ate surrounded by an intact basement membrane. After 24 h of culture in serum-free medium, only 20.4% of these follicles attached to a plastic substrate. We show ed that covering the plastic with extracellular matrix proteins (i.e., fibronectin, collagen Type I and matrigel) significantly increased th e percentage of attached follicles to 76.0, 65.2 and 80.4%, respective ly, while laminin had no effect (18.6%). When preantral follicles were embedded within three-dimensional collagen gels, no loss of follicles was observed. Restoring surface interactions between preantral follic les and the extracellular matrix in vitro, either in a two- or a three -dimensional system, might be important for maintaining follicular via bility and growth in the future.