慢性缺氧大鼠心肌肌浆网功能及其钙泵基因表达的动态变化

THE CHANGES OF SARCOPLASMIC RETICULUM FUNCTION AND GENE EXPRESSION OF Ca 2+ PUMP IN RAT HEART DURING CHRONIC HYPOXIA

将实验大鼠放置模拟５０００ｍ海拔高度低压舱内１、２和４周。结果表明：与对照组比较，１，２和４周组动物的心肌重量分别增加１５％，１８％和５７％；心肌ＳＲＣａ２＋摄取分别降低３３％，３８％和５３％；心肌ＳＲＣａ２＋ＡＴＰａｓｅ活性分别降低５４％，６０％和７４％；钙泵ｍＲＮＡ含量（基因表达分别降低１４％，４６％和６８％。这些结果提示，缺氧导致的ＳＲ钙泵功能降低可能是心肌功能受损的重要生化基础之一，而钙泵数目减少可能是钙泵功能降低的分子生物学机制。

Wistar rats were exposed to 5000m above sea level hypoxia in a hypobaric chamber for 1, 2 and 4 weeks respectively. The effects of hypoxia on the myocardium weight, myocardium sarcoplasmic reticulum (SR) calcium uptake, SR Ca 2+ ATPase activity and its gene expression were observed.The results showed that the myocardium weights increased by 15%, 18% and 57%, SR calcium uptakes decreased by 33%, 37% and 52%, SR Ca 2+ ATPase activities decreased by 54%, 60% and 74% and its mRNA contents (gene expresseion) also decreased by 14%,46% and 68% after 1, 2 and 4 weeks of hypoxia respectively, as compared with those of the control group. These results suggest that the decrease in SR calcium pump function induced by hypoxia may be one of the important biochemical bases of the cardiac hypofunction and the decrease in its mRNA content may be an important molecular mechanism responsible for the decrease in SR calcium pump function.