title: Apoptosis is an adaptive response in bovine preimplantation embryos that facilitates survival after heat shock.
abstract: 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 > or =16-cell stage at day 4 after insemination. Heat shock of 41 degrees 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.
authors.affiliation: Department of Animal Sciences, University of Florida, P.O. Box 110910, Gainesville, FL 32611-0910, USA.
authors.forename: F F
authors.initials: FF
authors.lastname: Paula-Lopes
authors.forename: P J
authors.initials: PJ
authors.lastname: Hansen
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D017209:Apoptosis; D001755:Blastocyst / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D001757:Blastomeres / Q000648:ultrastructure; D020169:Caspases / Q000378:metabolism; D002417:Cattle / Q000196:embryology* / Q000502:physiology; D002452:Cell Count; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D005314:Embryonic and Fetal Development; D018869:Heat-Shock Response; D020287:In Situ Nick-End Labeling; D009842:Oligopeptides / Q000494:pharmacology
chemical_list: D015853:Cysteine Proteinase Inhibitors; D009842:Oligopeptides; C110772:benzoylcarbonyl-aspartyl-glutamyl-valyl-aspartyl-fluoromethyl ketone; D020169:Caspases