Effect of follicular fluid on the surface ultrastructure of rat granulosa cells in vitro.

Abstract

Surface ultrastructural changes of rat granulosa cells during luteinization in vitro, as well as the effect of cow follicular fluid on this process, were studied by means of scanning electron microscopy (SEM). Granulosa cells appeared similar in control and follicular fluid media during the first day of incubation, but exhibited striking differences after 3 days; luteinized cells are enlarged and exhibit a flat and smooth surface on which blebs protrude. Cells under the influence of follicular fluid, even with LH, do not enlarge as much; they tend to retain their original thickness and their surface exhibit not only blebs but also numerous microvilli and filopodia structures; sometimes these cells show a fibroblastic appearance. These SEM results confirm our previous light microscopic observations and provide new information on a possible control by follicular fluid of the differentiation of the granulosa cell membrane needed for luteinization.