Apoptosis is an adaptive response in bovine preimplantation embryos that facilitates survival after heat shock

• Published in: Biochemical and biophysical research communications 2002-07, Vol.295 (1), p.37-42
• Main Authors: Paula-Lopes, F.F, Hansen, P.J
• Format: Article
• Language: English
• Subjects: Adaptation, Physiological; Animals; Apoptosis; Blastocyst - cytology; Blastocyst - drug effects; Blastocyst - physiology; Blastomeres - ultrastructure; Caspases - metabolism; Cattle - embryology; Cattle - physiology; Cell Count; Cysteine Proteinase Inhibitors - pharmacology; Embryo; Embryonic and Fetal Development; Heat shock; Heat-Shock Response; In Situ Nick-End Labeling; Oligopeptides - pharmacology; z-DEVD-fmk
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/S0006-291X(02)00619-8

Heat shock compromises development of preimplantation bovine embryos and the percentage of blastomeres labeled as TUNEL-positive. It was hypothesized that TUNEL labeling represents apoptosis and that apoptosis after heat shock is beneficial for continued embryonic development. To test these hypotheses, experiments were performed with z-DEVD-fmk, an inhibitor of group II caspases, on heat shock responses of embryos ⩾16-cell stage at day 4 after insemination. Heat shock of 41 °C for 9 h increased group II caspase activity and the proportion of TUNEL positive cells; z-DEVD-fmk blocked these effects. The reduction in development of embryos exposed to heat shock for 6–9 h was magnified in the presence of z-DEVD-fmk. Results indicate that group II caspases mediate heat-induced apoptosis in bovine embryos and that inhibition of these caspases has a detrimental effect on embryonic resistance to heat shock. Apoptosis can be viewed as an adaptative mechanism to allow embryonic survival and development following stress.