Comparison of the Effects of Oviductal Cell Coculture and Oviductal Cell-conditioned Medium On the Development and Metabolic-activity of Cattle Embryos

摘要

The objective of this study was to compare the development and metabolic activity of cattle embryos co-cultured with bovine oviductal cells or cultured in serum-free medium previously conditioned by bovine oviductal cells. Zygotes were produced by in vitro fertilization of oocytes from bovine ovaries obtained from an abattoir. Development to the four-cell stage occurred by 48 h after fertilization in both culture systems, but co-cultured embryos reached the 16-cell stage by 96 h, whereas those cultured in conditioned medium did not do so until 24 h later. Similarly, the morula and blastocyst stages were reached 24 h earlier in co-culture than in conditioned medium. There were significantly more cells in the blastocysts from co-culture (96.8 +/- 6.1 versus 56.7 +/- 3.3; P less than or equal to 0.0001). The metabolism of glutamine did not differ between embryos cultured in the two systems, but the metabolism of glucose was significantly greater in embryos cultured in conditioned medium. The first significant increase in glucose metabolism occurred between the four-cell and the 16-cell stages in embryos cultured in conditioned medium, but occurred between the 16-cell and morula stages in the co-cultured embryos, such that the glucose metabolism was significantly greater at the 16-cell stage in embryos cultured in conditioned medium compared with co-cultured embryos (6.5 +/- 1.0 versus 2.5 +/- 0.4 pmol per embryo per 3 h, P less than or equal to 0.0001). The concentration of glucose was significantly less, and that of lactate significantly greater, in co-culture medium than in conditioned medium. The results suggest that the activity of enzymes involved in glucose transport or metabolism in the early cattle embryo can be affected by the prior culture conditions, and that a high rate of glucose metabolism may be unfavourable for development.