ABSTRACT
PROBLEM: The type I interferon (IFN), IFN-tau (τ), is the primary embryonic signal for pregnancy maintenance in ruminants. This study determined the effects of heat shock upon IFN-τ (IFNT) gene expression by bovine blastocysts in vitro. METHOD OF STUDY: In vitro-produced blastocyst-stage embryos were exposed to 42°C for 4 hr, and mRNA for heat-shock protein 70 (HSP70) and IFNT quantified. RESULTS: Heat shock increased both HSP70 and IFNT expression. There was a significant correlation between HSP70 and IFNT transcript levels irrespective of whether a blastocyst had been exposed to heat shock or not. CONCLUSION: The increase in IFNT as a result of heat shock suggests that a proportion of the variation in IFNT expression observed in blastocyst-stage embryos is a response to stress.
