Development of 5-day rabbit blastocysts after culture at 37 degrees C.

Abstract

The rabbit ovum readily cleaves to the late morula or early blastocysts stage upon culture, but difficulty has been experienced in obtaining further develop¬ ment in vitro. The cultured zygotes remain viable and come to term if trans¬ ferred into host uteri. Expanded blastocysts have been cultured in vitro at approximately 37e C with some success (Brachet, 1912; Waterman, 1932; Pincus & Werthessen, 1938; Chang, 1950; Lutwak-Mann, Hay & Adams, 1962), but their successful development following transfer has not been re¬ ported. However, 5-day rabbit blastocysts will increase in size (Daniel, 1965) when cultured at 37° C in a modification of the cell culture medium F,0 of Ham (1963). The increase occurred after both 4 and 24 hr in modified F10 alone, but added serum was required to match the size range attained in vivo. The purpose of this investigation was to culture such blastocysts in vitro at 37° C, in the modified F)0 medium with and without serum added, and to test the capacity of the cultured blastocysts to develop into normal foetuses. Mature, Dutch-Belted does weighing more than 1-75 kg were used (Staples & Holtkamp, 1966). One hundred and eleven virgin does were utilized as blasto¬ cyst donors: fifty-eight post-partum does served as recipients of control and cultured blastocysts. Donor females received an ovulating dose of luteinizing hormone (lh) and