Changes in Cell Adhesion Molecules during Follicular Atresia in Porcine Ovaries.

Abstract

Abstract. Determination of the expression level and localization of cell adhesion molecules is crucial for understanding the mechanism of maintenance and remodeling of the ovarian follicle structure. We immunocytochemically investigated expression of the cell adhesion molecules, "classic" cadherins and β-catenin, in developing and/or atretic follicles of porcine ovaries. Healthy follicles showed strong staining for cadherin-8 and β-catenin in granulosa cells tightly attached to the basement membrane, and moderate/weak staining was seen on the inner surface of the granulosa cell layer. Strong VE-cadherin expression was seen in a single cell layer attached to the basement membrane in the theca interna layer of healthy follicles. The expression of cadherin-8, β-catenin and VE-cadherin decreased during follicular atresia. No positive staining was observed for R-cadherin, E-cadherin, Tcadherin, BR-cadherin or P-cadherin, and a weak positive reaction for N-cadherin was seen only in the granulosa cells of healthy and early atretic follicles. These findings indicate that cadherin-8, Ncadherin and VE-cadherin have important roles in follicular development and/or degeneration, and that decreases in the expression of these cadherins are involved in follicular atresia in porcine follicles.

Changes in Expression and Localization of Connexin 43 mRNA and Protein in Porcine Ovary Granulosa Cells during Follicular Atresia

“…We confirmed the up-regulation of the mRNA expression of ST6Gal I, which is a α2,6 sialyltransferase and catalyzes the transfer of α2,6-sialic acid in cell-membranous glycoproteins, in granulosa cells during follicular atresia [24]. Moreover, our previous findings on extracellular matrix (ECM) components [32,33] and cell adhesion factors, cadherins and β-catenin [34] in porcine follicles showed that the cell adhesion factors act as a survival factor, and intracellular signaling through these factors may depend on the protein tyrosine-kinase cascade [35]. It is considered that the expression of cell death receptors [36][37][38][39] and decoy receptors [40,41], and apoptosis inhibiting factors [42] also depends on cell to cell contact through the cell adhesion factors.…”

TRADD is Involved in Apoptosis Induction in Granulosa Cells during Atresia in Pig Ovaries.

“…More than 99% of follicles selectively undergo atresia and disappear during follicular development in mammalian ovaries. Such atretic degeneration may be explained by selective apoptosis of granulosa cells [24][25][26][27][28][29][30]. Many researchers believe that the cell death ligandreceptor system plays critical roles in selective apoptosis of granulosa cells during follicular atresia.…”

TRAIL-Decoy Receptor-1 Disappears in Granulosa Cells of Atretic Follicles in Porcine Ovaries.

“…Frozen sections of follicular sections of pig ovaries were prepared as described previously [38][39][40][41][42]. Briefly, individual preovulatory antral follicles, 3-5 mm in diameter, were dissected from ovaries obtained from mature sows at a slaughterhouse.…”