缺血/再灌注时心肌细胞线粒体钙超载及保护的超微结构“定量”观察

A time—related study about morphometry in myocardial ultrastructure and Ca distribution in ischemia and reperfusion damage and the protective effect of Danshen for the heart

本文应用焦锑酸分子探针、X射线显微分析及图像分析方法,对不同缺血时相再灌注时心肌细胞线粒体的体积密度及其内含物性质和含量进行了定量分析。结果表明:线粒体内含物为含钙的化台物,线粒体及其钙盐颗粒的体积密度随着缺血时间的延长而逐渐增加,并被再灌注所加重,尤以缺血40min再灌注组最明显,而缺血60min再灌注组线粒体钙盐颗粒的体积密度较缺血40min再灌注组明显减少,这提示不同缺血时间的心肌对再灌注的反应有一定的规律性,是由可逆向不可逆转变的过程,在本实验条件下,缺血40min至60min可能是可逆性与不可逆性再灌注损伤的临界点。应用丹参制剂能明显减少钙盐颗粒的体积密度,提示丹参对心肌“钙超载”呈明显的保护作用,具有良好的钙拮抗效应。

Calcium overload has been discovered in the ischemia and reperfusion injury of the heart recently, but there were less reports about changes in myocardial Ca distribution under this same condition by electronmicroscopy. Using the potassium-pyroantimonate method and X-ray microanalysis, we studied cytochemical calcium localization in the rabbit's myocardium at various time periods of ischmia with or without subsequent reperfusion. At the same time, we had the morphometric estimation of Ca granule volume density in the mitochondria by TAS(texture analysis system) and evaluated Danshen's protection for ischemia and-reperfusion injury. The results showed that mitochondrial Ca granule volume density increased significantly with the development of ischmia and post-ischemic reperfusion, especially during reperfusion following 40min of ischemia, however following 60min of ischemia, Ca granule volume density decreased than that observed following 40 min of ischemia. This meant that the limit time point for reversible and irreversible injury could be in the range of 40～60min of ischemia. Danshen pretreatment to the rabbits reduced Ca granule volume density significantly. This demostruted that Danshen acted as a calcium antagonist and contributed an outstanding protection to the myocardial calcium overload.