X线照射增加大鼠心肌对缺血/再灌注损伤的敏感性*

 目的：观察胸部X线放射治疗大鼠对心肌缺血/再灌注损伤的敏感性。方法：用胸部单次照射X线20 Gy构建放射性心脏损伤模型，采用完全随机分组方法将Wistar大鼠分为假损伤组、损伤组、假损伤+假手术组、假损伤+缺血/再灌注组、损伤+假手术组和损伤+缺血/再灌注组，于创伤后2周行心肌缺血/再灌注。通过BL-410生物信号记录分析系统记录各组大鼠左心室发展压（LVDP）、左心室压力上升的最大速率（+dp/dtmax）和左心室压力下降的最大速率（-dp/dtmax）；采用ELISA方法检测大鼠血清心肌肌钙蛋白I（cTnI）和肌酸激酶同工酶（CK-MB）；用BI2000图像分析软件测定心肌梗死面积占总面积的百分比。结果：损伤+缺血/再灌注组离体心功能明显低于假损伤+缺血/再灌注组（P＜0.01），损伤+缺血/再灌注组血清cTnI和CK-MB水平显著高于假损伤+缺血/再灌注组（P＜0.01），损伤+缺血/再灌注组心肌梗死面积显著大于假损伤+缺血/再灌注组（P＜0.01）。结论:X线照射增加大鼠心肌对缺血/再灌注损伤的敏感性。

X-ray irradiation increases sensitivity of myocardium to ischemia/reperfusion injury in rats

AIM：To observe the sensitivity of myocardium to ischemia/reperfusion (I/R) injury in the rats with chest radiotherapy. METHODS：The radiation-induced heart disease model was established by local 20 Gy of X-ray irradiation in the chest. Male Wistar rats (n=42) were randomly divided into 6 groups:sham trauma group, trauma group, sham trauma+sham operation group, sham trauma +I/R group, trauma+sham operation group and trauma+I/R group. The rats were subjected to 30 min of ischemia and 1 h of reperfusion 2 week after trauma. The left ventricular developed pressure (LVDP) and ±dp/dtmax were recorded by BL-410 biological signal recording and analysis system. The serum cardiac troponin I (cTnI) and creatine kinase isoenzyme (CK-MB) were measured by ELISA. The myocardial infarct size was determined by nitroblue tetrazolium(NBT) staining method and BI2000 image analysis software. RESULTS：Compared with sham trauma+I/R group, significant decreases in LVDP and ±dp/dtmax were observed in trauma+I/R group (P<0.01) with significant increases in the infarct size and the concentrations of cTnI and CK-MB (P<0.01). CONCLUSION:Chest X-ray irradiation increases the sensitivity of myocardium to I/R injury in rats.