IMPROVEMENT IN BOVINE EMBRYO PRODUCTION IN-VITRO BY GLUTATHIONE-CONTAINING CULTURE MEDIA

Bovine oocytes were matured, fertilized, and cultured (TCM 199 with se rum and co-culture) in vitro (IVMFC) with addition, during different p hases of the procedure, of antioxidants: superoxide dismutase (SOD) an d reduced glutathione (GSH). The addition of SOD (1,500 or 3,000 IU/ml ) did not improve proportions of oocytes undergoing cleavage or the de velopment of embryos to morula and blastocyst stages. The cleavage rat es were significantly lower than in the control group (CTR 57.5%) when SOD was present during the insemination interval (IVF) or throughout the entire procedure (IVMFC). Thus when the lower concentration was pr esent for IVF and IVMFC, 35.1% and 36.4% of inseminated oocytes cleave d (P < 0.01 compared to CTR) and cleavage results with the higher conc entration during IVF and IVMFC were 38.5% and 29.2% (P < 0.025 and P < 0.001 compared to CTR, respectively). Significant improvements in pro portions of oocytes undergoing cleavage (84.5% vs. 57.0%, P < 0.001) a nd morula/blastocyst development (33.3% vs. 13.9%, P < 0.005) were ach ieved when GSH (1 mM) was added to the culture medium. In a defined me dium for culture (mSOF and BSA) the presence of SOD (3,000 IU/ml) was ineffective, but in a defined medium supplemented with GSH (1 mM) at d ay 6 postinsemination (i.e., when 90% of developing embryos were in 8- 16 cell stages), development to the morula and blastocyst stages was s upported for 35.5% of cultured oocytes (P < 0.005 compared to 19.2% fo r CTR). These data suggest that bovine embryos are sensitive to oxidat ive stress and that medium supplementation with the radical scavenger glutathione can improve embryo development in vitro. (C) 1996 Wiley-Li ss, Inc.