Possible role of interferon-τ on in vitro development of bovine embryos

The effect of interferon-τ on in vitro development of bovine embryos was investigated. After in vitro fertilization, embryos developed to the morula stage were cultured for 3 days in TCM-199 or CR1 medium containing BSA or FCS supplemented with or without recombinant IFN-τ produced by a baculovirus expression system. Addition of baculovirus-expressed IFN-τ (100 ng/ml) significantly promoted development to the blastocyst stage in both culture media. Addition of E. coli expressed IFN-τ (2 μg/ml) also significantly promoted the embryonic development. Supplementation of BSA or FCS did not affect the growth-promoting effect of IFN-τ. To determine whether the growth-promoting effect of IFN-τ is related to the interferon type I receptors that bind to type I interferon such as IFN-α, embryos were cultured with IFN-α. Although IFN-α significantly promoted the development, a much higher concentration (25 μg/ml) was required than IFN-α. A reverse transcription polymerase chain reaction analysis revealed the expression of mRNA encoded type-I IFN receptor subunit from morula to blastocyst stage embryos. The overall results suggest a novel function for IFNs in promoting embryonic development and the effect may be related to type-I IFN receptor expressed in the early stages of preimplantation embryos.