Sato et al. reported that hyaluronic acid-like GAGs possess viability-promoting activity for porcine and murine oocytes in vitro. We found previously that the proportion of degenerated porcine embryos was lower in the presence than in the absence of hyaluronic acid. By this beneficial effect, 70% of 1- and 2-cell-stage embryos developed to the blastocyst stage without degeneration. In the present study, the proportions of fragmented and degenerated embryos were high at all concentrations of hyaluronic acid during culture, and only 17% of the inseminated oocytes developed to the blastocyst stage (Table 4). It has been reported that the frequent occurrence of fragmented and degenerated embryos following in vitro fertilization is due to unfertilized and polyspermic oocytes. ventolin inhaler
In the present study, polyspermic fertilization was frequently observed in the porcine oocytes (61% in Table 1), although 92% of the oocytes were penetrated by spermatozoa. In the present study, furthermore, the percentage of IVM and IVF oocytes developing to blastocysts on a cleaved oocyte basis (2- to 8-cell stage after 2 days in culture) was 60% (blastocyst stage after 6 days in culture/2-8-cell stage after 2 days in culture: 12/9+11 in Table 4) in 0.5 mg/ml hyaluronic acid-supplemented medium.