Submission Number: KOJ-4-25-25

Abstract Number: 364

EFFECT OF BOVINE INTERFERON TAU ON THE EARLY DEVELOPMENT OF BOVINE EMBRYOS.

K Kimura ¹, H Iwata ², M Aoki ¹ and M Hirako ¹

National Grassland Research Institute, 768 Nishinasuno, Tochigi 329-2793, Japan ¹
Kobe City Horticulture Promoting Association, Kobe 651-2204, Japan. ²

Abstract:
Bovine interferon tau(bIFN-tau) is the major protein secreted from conceptuses during early pregnancy. This protein involves in the process of maternal recognition of pregnancy. It acts on the uterine endometrium and blocks the pulsatile secretion of PGF2alpha. Many studies have focused on the effect of bIFN-tau on the uterine endometirium. However, there were a few studies about the role of bIFN-tau in bovine embryo. Therefore, we investigated the effect of bIFN-tau on the development of bovine embryos. In the first experiment, bovine embryos derived from IVM-IVF-IVC were used in this study. Ovaries were collected at a local abattoir. Cumulus-oocyte complexes (COCs) were aspirated from small antral follicles. The COCs are matured for 22hr and inseminated for 6hr. Then, oocytes were washed and cultured in mSOF containing 1 % FCS. Cumulus cells were removed at 48hr of culture. The embryos, developed to morula stage on 5 days after insemination, were transferred and cultured in m-SOF containing 5% FCS supplemented with 15 microgram/mL bIFN-tau (produced by E. coli) or BSA (control). The number of embryos that reached the blastocyst stage at 6 and 7 days after insemination was compared. In the next experiment, it was investigated whether IFN receptor genes were expressed in bovine embryo. Messenger RNA (m-RNA) was extracted from 34 embryos and used for RT-PCR. After RT-PCR, PCR was performed again using nested primers and the RT-PCR products as templates. The products were resolved by agarose gel electrophoresis. The development rates to blastcyst on day 6 and 7 post insemination in culture with bIFN-tau were 58 and 69 %, respectively, whereas they were 44 and 54% in the control. There were significant differences between two groups in the development rate to blastosyst stage on day 6 and 7 (day 6; P<0.05, day 7; P<0.01). It was indicated that bIFN-tau improved the development rate of bovine embryos in vitro. The expression of bovine interferon receptor genes was detected by the second PCR, although no band was found in gels after RT-PCR. These results suggested that the effect of bIFN-tau on the development of bovine embryo might be elicited by the its binding to the receptors. .

Keywords: IFN-tau, receptor, bovine embryo

This abstract is being presented at: 8:00 AM in session:
Preimplantation Embryo/Fetus