Tumor necrosis factor alpha inhibits in vitro bovine embryo development through a prostaglandin mediated mechanism

Mastitis or other infectious diseases have been related to reduced fertility in cattle. Inflammatory cytokines such as tumor necrosis factor alpha (TNF alpha) are released in response to infection and may have negative effects on embryo development. In the current study the effect of exposure to TNF alpha on the development of in vitro fertilized bovine embryos was examined. Indomethacin, a prostaglandin synthesis inhibitor, was used to determine if blockade of prostaglandin synthesis would alter the effects of TNF alpha. Ovaries were obtained from a local abattoir and immature COC were isolated from 2-10 mm follicles, in vitro matured and fertilized. After fertilization, groups of presumptive zygotes were randomly placed into either control development medium, medium containing 25 ng/mL TNF alpha or medium containing 25 ng/mL TNF alpha plus 1 mu g/mL indomethacin. The proportion of blastocysts formed was assessed at day 7 of culture. Fewer embryos exposed to TNF alpha alone reached the blastocyst stage (17.5 +/- 2.4%, P < 0.01) compared with controls (30.5 +/- 2.4%) or embryos developed in TNF alpha plus indomethacin (25.8 +/- 2.8%). There was no difference between control embryos and embryos developed in TNF alpha plus indomethacin. These results indicate that TNF alpha is inhibitory to the in vitro development of bovine embryos and that this inhibition may be mediated by prostaglandins because it can be blocked by indomethacin.