Collagen matrix influences the morphologic features and steroid secretion of human granulosa cells

Steroid secretion and structure of granulosa cells on floating collagen gels were compared with those of cells grown on plastic. Granulosa cells from follicles of gonadotropin-treated women were plated either onto dishes coated with type I collagen or onto plastic dishes. Medium containing serum was removed after 24 hours, defined medium was added, and the gel was floated. Medium was changed daily for 3 days, after which the granulosa cells were prepared for light and electron microscopy. Cells grown on collagen secreted significantly more estradiol and progesterone than those grown on plastic during the 3 days of culture. The round multilayered granulosa cells on collagen had abundant mitochondria and lipid droplets and they formed numerous intercellular junctions. On plastic surfaces, flat granulosa cells grew as a monolayer with few junctions and less abundant mitochondria or lipid droplets. We conclude that growth on floating collagen promotes structural changes of human granulosa cells that enhances cell interaction and secretion of steroid hormones.