烫伤大鼠心肌收缩功能与细胞内游离钙的研究

目的：观察烧伤后心肌功能与心肌细胞浆游离钙浓度之间的关系。方法：成年SD大鼠Ⅲ度烫伤，面积43％TBSA，另设对照组（假烫组），大鼠烫伤24h后，对心脏进行离体Langendorff灌注，通过导管连接心功能记录仪，持续监测左心室收缩压力的动态变化（left ventricular develop pressure,LVDP)，于灌注液中加入TF－BAPTA前后，检测心脏的^19F和^31P磁共振波谱图。结果：与对照组相比，烫伤大鼠心脏的LVDP降低了40％（P＜0．01），心肌细胞胞浆游离钙浓度高出对照组4倍（P＜0．01），心肌细胞摄入TF－BAPTA后，心脏LVDP仅降低15％－20％，PCr/Pi比值下降，但ATP无变化。结论：体表烧伤使心脏的收缩功能受抑制，这种功能抑制与心肌细胞胞浆游离钙浓度增高同时存在。

A study on the myocardial contractile function and intracellular free calcium in scalded rats

Objective To explore the relationship beween postburn myocardial function and intracellular free calcium concentration. Methods Sprague-Dawley (SD) rats were employed as the model in which 7 were inflicted with 43% TBSA degree scalding (S group) and 7 as sham scalding control group (C group).The hearts of the injured rats were isolated and perfused in vitro by Langendorff method after 24 postburn hours (PBHs).The hearts were connected to a cardiac function monitor,and the dynamic changes in left ventricular develop pressure (LVDP) were continuously monitored.The cardiac 19 F and 31 P NMR spectroscopy was determined before and after and TF-BAPTA was added to the perfusate. Results When compared with those in C group,the LVDP of scalded rat heart decreased by 40% (P<0.01),and the myocardial cytoplasmic free calcium concentration was four times above that in C group (P<0.01).After TF-BAPTA was taken by myocytes,cardiac LVDP only decreased by 15% to 20%,and the PCr/Pi ratio decreased,while there was no change in ATP. Conclusion Myocardial contractile function could be inhibited after burn injury,which might be related to the increase of myocardial cytoplasmic free calcium concentration.