Characterization of cytoskeletal proteins in follicular structures of cows with cystic ovarian disease.

The distribution of intermediate filaments (vimentin, cytokeratins, desmin) and microfilaments (alpha-smooth muscle actin and muscle specific actin) was studied immunohistochemically in bovine ovaries, with and without cystic ovarian disease. The immunohistochemically stained area (IHCSA), was quantified by image analysis, to evaluate the expression of these cytoskeletal proteins in the follicular wall of healthy antral, atretic, and cystic follicles. The granulosa cell layer of cystic follicles and atretic follicles had a significantly larger IHCSA for vimentin than did healthy antral follicles. Cytokeratins reacted lightly in the granulosa cells of antral follicles of normal ovaries, whereas granulosa cells of atretic and cystic follicles showed significantly higher IHCSA values. Immunohistochemical localization of desmin, muscle specific actin, and alpha-smooth muscle actin was restricted to the theca externa. This study supports earlier suggestions that strongly positive reactions with vimentin and cytokeratin antibodies observed in the granulosa cells of cystic follicles are due to the reorganization that occurs in the follicle during the process of cystic development, and are associated with changes in the expression of cytoskeletal proteins that are essential to proper cellular functioning.