Medycyna Wet. 63 (1), 23-28, 2007
Włodarczyk R., Izdebska M., Grzanka A., Jaśœkowski J. M.
Influence of heat shock on the development of bovine embryos in the early preimplantation stage
This article presents the results of thermal stress on embryos exposed to heat stress during early preimplantation stage. The repercussions of heat stress are, among others, uterus hyperthermia, the inhibition of embryonic development and death. It seems that embryos are most frequently endangered or damaged by heat shock the early stage of development (2-4 cells), because during this period most embrionic genes remain inactive. Embryos at a more advanced stage of development are able to activate a range of mechanisms in order to protect embryonic cells against the destructive influence of heat shock. One of the defensive reactions activated by embryos is the increased secretion of antioxidants and HSP; i.e. Heat Shock Proteins. Apoptosis is a natural process activated as a response to heat shock, eliminating the damaged cells. Consequently, some embryos at the stage of ³ 8 cells have developed mechanisms responsible for activating apoptosis, thus damaged cells go under selective and controlled elimination with omitting general necrosis. If damage concern a small number of embryonic cells, the embryo is still able to continue its development. Subtle biological mechanisms responsible for embryonic reaction to heat shock are still unknown. There are attempts to explain a part of them of through laboratory research.
Key words: bovine, embryo, heat shock