On the Structural Changes of Granulosa Cells Cultured in vitro

Abstract

Granulosa cells from porcine ovarian follicles were cultured in vitro in standard medium and in medium supplemented with HCG. After culture the cellular 3β HSD enzymatic activity was evaluated and the cells were studied by TEM and SEM. A stereological evaluation of the smooth and rough endoplasmic reticulum was carried out. The results indicate that the cultured cells undergo a luteinization process which is more evident in the presence of HCG. In fact, in comparison with the controls, in these cells the enzymatic activity is higher, the rough endoplasmic reticulum decreases and the smooth endoplasmic reticulum increases, the cytoplasm shows lipid droplets and vesicular mitochondria. The cell surface develops a number of microvillus-like evaginations.

The ultrastructure of human cumulus-corona cells at the time of fertilization and early embryogenesis. A scanning and transmission electron microscopic study in an in vitro fertilization program.

“…This morphodynamic pattern well correlates with a gradual establishment of the steroidosynthetic capability in the CC cells that appears to be enhanced during and after fertilization. It is worth noting that such a cytoplasmic maturation is similar and contemporaneous to that occurring in the developing corpus luteum (GULYAS, 1984) and in cultured granulosa cells (BALBONI and ZECCHI, 1981;ROTMENSCH et al, 1986;AMSTERDAM and ROTMENSCH, 1987), confirming our hypotheses that the CC cells are capable of undergoing luteinization, and that their steroidosynthetic activity may be useful for the embryo, particularly when its growth and metabolism increase.…”

“…Surface expansions have been described by SEM on the surface of the CC cells of various mammals, including humans (GWATKIN and CARTER, 1975;SUNDSTROM, 1982;FLECHON et al, 1986). Similar structures, even increased in number, are also present on the surface of granulosa cells that are undergoing luteinization ( VAN BLERKOM and MOTTA, 1979;MAKABE et al, 1980;MOTTA and VAN BLERKOM, 1980;BALBONI and ZECCHI, 1981;MOTTA and MAKABE, 1981).…”

“…Free ribosomes and polysomes appeared also slightly reduced in this latter group. These aspects are also present in cultured granulosa cells that undergo luteinization (BALBONI and ZECCHI, 1981;AMSTERDAM and ROTMENSCH,1987). The presence of elements of rough endoplasmic reticulum and free ribosomes, together with the other organelles, makes the highly developed metabolic machinery of the luteinizing CC cells capable of also being involved in proteic synthesis, particularly during the initial phases of the process.…”

“…The presence of microvilli, as well as their increase in number after fertilization, may be due to an increased necessity for a metabolic exchange with the culture medium by cells that gradually acquire a complex steroidosynthetic capability, as hypothesized for the other granulosa cells ( VAN BLERKOM and MOTTA, 1979;MAKABE et al, 1980;BALBONI and ZECCHI, 1981). Microvilli also might represent a morphodynamic response of the CC cells to a given luteinization stimulus, as has been reported for the cells destined to form the corpus luteum (GULYAS, 1984;ROTMENSCH et al, 1986).…”

“…The presence of elements of rough endoplasmic reticulum and free ribosomes, together with the other organelles, makes the highly developed metabolic machinery of the luteinizing CC cells capable of also being involved in proteic synthesis, particularly during the initial phases of the process. This additional activity of the CC cells can be likely related to the production of the enzymes involved in steroidosynthetis, as occurs in the luteinizing parietal granulosa cells (BALBONI and ZECCHI, 1981;GULYAS, 1984).…”