Apoptosis induced by changes in the temperature during whole embryo culture of postimplantation rat embryos / 대한해부학회지

ABSTRACT

It has been reported that heat shock (43degrees C) induces an episode of cell death in developing central nervous system as part of pathogenesis leading to abnormal growth and development. Cell death induced by heat shock is likely to occur by a process termed apoptosis. On the other hand, protective role of mild heat shock on heat shock-induced apoptosis has also been suggested. In this study, the effect of 43degrees C heat shock on the induction of apoptosis was investigated in detail firstly by determining internucleosomal DNA fragmentation (DNA laddering) and secondly by determining apoptotic bodies using TUNEL (TdT-mediated dUTP-biotin nick end labeling). In addition, the effect of mild heat shock (42degrees C) on the apoptotic process was examined. In order to modulate the environmental temperatures of the developing embryos, we used whole embryo culture technique. DNA fragmentation and apoptotic body was induced a little by 42degrees C exposure but embryos exposed to 43degrees C showed strong DNA fragmentations. In comparison, the amount of DNA fragmentation was significantly reduced in embryos with 42degrees C pretreatment than 43degrees C group. In the control embryos (37degrees C exposure), basal levels of DNA fragmentation and apoptotic bodies were observed. From this study, it was evident that thermotolerance could protect the early postimplantation embryos from hyperthermia.