Protective effect of heat-stress preconditioning on anoxic endothelial cells and its mechanism

AIM:To observe the protective effect of heat stress preconditioning on endothelial cells under anoxia and explore its mechanism. METHODS:The endothelial cells were divided into 4 groups: (1) anoxia; (2) heat stress; (3) heat stress preconditioning + hypoxia; (4) control. LDH activity was measrued by using Automatic Biochemistry Analysis-Meter. Cell death rate was determined by trypan blue, NO production was tested by measuring NO₂^-/NO₃^- content in cellular culture medium by using Griess assay. RESULTS:LDH release and cell death rate of the anoxia endothelial cells significantly increased compared with control; 39℃ heat stress preconditioning reduced those increment by 29.47%, 33.67% respectively. 41℃ heat stress preconditioning has no protection against the anoxia-induced injury in endothelial cells. The NO production in anoxic endothelial cells decreased markedly. 39℃ heat stress preconditioning induced the increase in NO production in endothelial cells, but 41℃ heat stress preconditioning made the NOS activity decrease. The NO production was correlated negatively with LDH release and cell death rate in anoxic endothelial cells. CONCLUSION:The heat stress preconditioning within the limits can protect the endothelial cells from anoxia injury. The increase in NO in endothelial cells may play an important role in the mechanism of the protective effect.