PREIMPLANTATION DEVELOPMENT OF IN-VITRO-MATURED AND IN-VITRO-FERTILIZED OVINE ZYGOTES - COMPARISON BETWEEN COCULTURE ON OVIDUCT EPITHELIAL-CELL MONOLAYERS AND CULTURE UNDER LOW-OXYGEN ATMOSPHERE
Aj. Watson et al., PREIMPLANTATION DEVELOPMENT OF IN-VITRO-MATURED AND IN-VITRO-FERTILIZED OVINE ZYGOTES - COMPARISON BETWEEN COCULTURE ON OVIDUCT EPITHELIAL-CELL MONOLAYERS AND CULTURE UNDER LOW-OXYGEN ATMOSPHERE, Biology of reproduction, 50(4), 1994, pp. 715-724
The roles of medium composition, serum source, embryo coculture, and c
ulture under low O2 conditions on the development of in vitro-matured
and in vitro-fertilized (IVMF) ovine zygotes were investigated in thre
e separate experiments. In the first experiment, the proportion of coc
ultured IVMF zygotes developing to the blastocyst stage was significan
tly higher (38.0% vs. 3.5%; p < 0.05) than that of non-cocultured zygo
tes treated within three embryo culture media (TCM-199 + 10% fetal bov
ine serum [FBS]; bicarbonate-buffered, glucose-free synthetic oviduct
fluid medium [mod-SOFM] + 10% FBS; and bicarbonate-buffered BSA-free T
yrode's salt solution [mod-TALP] + 10% FBS) under a 5% CO, atmosphere
in air. In a second experiment, a significantly higher (p < 0.05) prop
ortion of cocultured zygotes placed in TCM-199 medium survived to the
blastocyst stage (37.4% blastocysts vs. 23.4% in mod-SOFM). No signifi
cant effect of serum (FBS vs. human serum [HS]) was observed on embryo
nic development, but coculture was confirmed to exert a significant in
fluence on development to the blastocyst stage. In the final experimen
t, survival of the embryo under a reduced oxygen (5% CO2:5% O2:90% N2)
atmosphere was investigated. In contrast to results in the initial ex
periments, embryonic survival was significantly higher (p < 0.05) in t
he non-cocultured treatment groups (21.9% blastocysts vs. 0.4% for coc
ultured zygotes). Serum source also had a significant (p < 0.05) influ
ence upon the development of non-cocultured zygotes: 32.3% of zygotes
cultured with HS progressed to the blastocyst stage vs. 11.5% of zygot
es cultured in FBS-supplemented medium. These results have characteriz
ed two distinct culture environments, each capable of supporting the d
evelopment of high frequencies of unselected IVMF zygotes to the blast
ocyst stage in vitro.