Prevention of spontaneous degeneration of mouse oocytes in culture by ovarian glycosaminoglycans.

Mouse follicular oocytes cultured for more than 72 h in modified Krebs-Ringer solution in vitro undergo spontaneous segmentation to form "blastomeres" with or without nuclear fragments or chromatin. Glycosaminoglycans (GAGS) isolated from bovine follicular fluid (bFF) and added to the suspending medium at concentrations of 0.25 mg/ml or greater prevented the occurrence of spontaneous segmentation in isolated cumulus-free mouse oocytes in a dose-dependent manner. The active material was isolated from bFF by chromatography on Dowex 1-X2. The fraction eluted with 0.5 M NaCl possessed the greatest biological activity. Preparations of purified bFF-GAGs and hyaluronic acid and chondroitin sulfate from a commercial source prevented the occurrence of segmentation. Hyaluronic acid was more potent than chondroitin sulfate. The present results show that GAGs prevent segmentation of oocytes in vitro.