| 摘 要： | Hyperlipidemia is an independent risk factor in the devel- opment of ischemic heart disease, which can increase myo- cardial susceptibility to ischemia/reperfusion （I/R） injury. Ischemic postconditioning （PostC） has now been demon- strated as a novel strategy to harness nature＇s protection against myocardial I/R injury in normal conditions. However, the effect of PostC on hyperlipidemic animals remains elusive. It has been shown in our previous study that PostC reduces the myocardial I/R injury, and hypoxia- inducible factor-1α （HIF-1α） may play an important role in the cardioprotective mechanisms of PostC on normal rats. Here, we tested the hypothesis that the cardioprotec- tion of PostC on hyperlipidemic rats is associated with the up-regulated HIF-1α expression. Male Wistar rats were fed with a high-fat diet for 8 weeks, and then randomly div- ided into five groups： sham, I/R, dimethyloxalylglycine （DMOG） ＋ I/R, PostC, and DMOG ＋ PostC group. The detrimental indices induced by I/R injury included infarct size, plasma creatine kinase （CK） activity and caspase-3 ac- tivity. The results showed that PostC could reduce the infarct size, when compared with the I/R group, which was consistent with the significant lower levels of plasma CK activity and caspase-3 activity, and that it increased the ex- pression of HIF-1α in hyperlipidemic rats. When DMOG was given before PostC to up-regulate HIF-1α protein level, the degree of I/R injury was attenuated. In conclu- sion, these data suggested that the up-regulation of HIF-1α may be one of the cardioprotective mechanisms of PostC against I/R injury in hyperlipidemic rats.
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