title: Increasing carbon dioxide from five percent to ten percent improves rabbit blastocyst development from cultured zygotes.
abstract: One-cell rabbit zygotes were cultured at 39 degrees C in basal synthetic medium II (BSM-II) with 5%, 10%, or 15% CO2 and humidified air to determine the effect of CO2 concentration on development in vitro. After 4 days in culture, 37% of the embryos grown in 10% or 15% CO2 had reached the hatching blastocyst stage, but only 10% of the embryos were hatching when cultured under 5% CO2 (P = 0.01). Over all blastocysts, cell numbers were 207, 246, and 205 for the 5%, 10%, and 15% CO2 treatments, respectively. In a second experiment to determine if there was a beneficial effect, particularly at the blastocyst stage, of a higher concentration of CO2, embryos were cultured 4 days in either 5% or 10% CO2 or for 2 days in 5% CO2 followed by 2 days in 10% CO2. The numbers of blastomeres per embryo and embryo diameter were greater (P < 0.05) in embryos cultured continuously in 10% CO2 or in 10% CO2 only during days 3 and 4 of culture than in embryos cultured continuously in 5% CO2. In a third experiment, one-cell rabbit zygotes were cultured with 5% or 10% CO2 in a defined, protein-free medium consisting of 1:1 RPMI 1640 and Dulbecco's modified Eagle's medium. The proportion of embryos hatching and cell counts were significantly greater (P < 0.01) when cultured in the presence of 10% CO2. These data indicate that a 10% CO2 atmosphere exerts a beneficial effect on the development of zygotes into expanding and hatching rabbit blastocysts in vitro.
authors.affiliation: Department of Animal Science, Cornell University, Ithaca, New York 14853-4801.
authors.forename: K
authors.initials: K
authors.lastname: Hallden
authors.forename: J
authors.initials: J
authors.lastname: Li
authors.forename: E W
authors.initials: EW
authors.lastname: Carney
authors.forename: R H
authors.initials: RH
authors.lastname: Foote
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000166:cytology*; D002245:Carbon Dioxide; D003470:Culture Media; D046508:Culture Techniques; D005314:Embryonic and Fetal Development; D011817:Rabbits
chemical_list: D003470:Culture Media; D002245:Carbon Dioxide