摘要目的 探讨烧冲复合伤大鼠心肌损伤及钙蛋白酶的变化规律.方法 128只雄性SD大鼠按随机数字表法分为对照组、烧伤组、冲击伤组、复合伤组各32只.对照组:37℃温水中12 s,烧伤组:94℃的沸水中12s,冲击伤组:5 g黑索今距离大鼠左胸壁75 cm爆炸,复合伤组:5g黑索今距离大鼠左胸壁75 cm爆炸后94℃的沸水中12s.伤后6、24、48、72 h4个观察点,采集腹主动脉血和心肌标本;测定左心室射血分数(EF)、左心室短轴缩短指数(FS);心肌组织HE染色;血清肌钙蛋白Ⅰ(CTnI)、肌酸激酶同工酶(CK-MB)检测;Tunel染色检测心肌组织细胞凋亡;实时荧光定量聚合酶链反应(RT-PCR)及Western印迹法分析心肌中钙蛋白酶mRNA及蛋白表达变化;荧光光度法检测钙蛋白酶活性.结果 复合伤组伤情变化明显,心肌间质水肿明显,可见大面积心肌细胞变性及崩解,中性粒细胞浸润数量增多.伤后24h烧伤组、冲击伤组、复合伤组心功能下降,EF和FS均显著低于对照组(均P＜0.05).复合伤组伤后72 h时FS和EF,48 h时FS均显著低于烧伤组、冲击伤组(均P＜0.05);复合伤组cTnI上升,各个时间点均显著高于对照组,48 h时均显著高于烧伤组与冲击伤组(均P＜0.05);复合伤组CK-MB伤后逐渐升高,24h时降低,48 h时再升高且均显著高于对照组与烧伤组(均P ＜0.05).伤后烧伤组、冲击伤组、复合伤组心肌凋亡指数均显著高于对照组(均P＜0.05),烧伤组24、48 h时分别为(25.3±4.0)、(28.8±5.3),均显著低于同时间点复合伤组的(43.3±9.4)、(53.3±10.4),烧伤组72 h时为(31.9±6.7),显著高于冲击伤组的(17.3±6.3)(均P＜0.05).各时间点复合伤组心肌组织中钙蛋白酶mRNA和蛋白相对表达量均显著高于对照组(均P＜0.05).复合伤组心肌钙蛋白酶活性伤后24h达到高峰,后逐渐下降,各时间点均显著高于对照组(均P＜0.05).结论 烧冲复合伤后大鼠出现心肌损伤,钙蛋白酶蛋白表达升高、活性增强.

abstractsObjective To study myocardial damage and rules of calpain change in rats with burnblast combined injury.Methods One hundred and twenty-eight male SD rats were randomly divided into control group,bum group,blast group,bum-blast group,with 32 rats in each group.Control group:37 degrees' warm water for 12 s;Burn group:94 degrees' boiling water for 12 s;Blast group:5 g cyclonite explode in 75 cm distance from left chest wall of rat;Burn-blast group:burn group and blast group combined modeling method.At 6,24,48,72 h observation points after injury,abdominal aorta blood samples and myocardial specimen were collected.Left ventricular ejection fraction (EF),left ventricular fractional shortening index (FS) were measured through color Doppler ultrasound instrument;Myocardial tissue was stained with hematoxylin-eosin (HE);serum cardiac troponin Ⅰ (CTnI) and creatine kinase isoenzyme (CKMB) were detected;detection of cell apoptosis in myocardial tissue was performed by terminal deoxynuclcotidyl transferase-mediated dUTP notch labehng technique (Tunel).Expression levels of calpain mRNA levd and protein were detected with Real-time fluorescent quantitative polymerase chain reaction (RT-PCR) and Western imprinting method analysis;calpain activity was detected by fluorescence spectrophotometry.Results The injury of burn-blast combined injured rats was obvious,including myocardial interstitial edema,large area of myocardial cell degeneration and disintegration and the number of neutrophil infiltration increased.Cardiac function decreased 24 h after injury in burn group,blast group,burn-blast group;both EF and FS were significant lower than those of control group (all P ＜ 0.05).FS at 48,72 h and EF at 72 h in burn-blast group were significantly lower than those of burn group,blast group at the same time points (all P ＜ 0.05);the level of cTnI in burn-blast group rose and was higher than control group at all time points,higher than the burn group,blast group at 48 h (all P ＜ 0.05).CK-MB in burn-blast group rats increased after injury,lowered at 24 h and rose again at 48 h.The level was significantly higher than control group and burn group (both P ＜ 0.05).Comparing to control group,myocardial apoptosis index in burn group,blast group and burn-blast group were significantly increased (all P ＜0.05).Those of burn group (25.3 ± 4.0) at 24 h and (28.8 ± 5.3) at 48 h were significantly lowered than burnblast group (43.3 ±9.4),(53.3 ± 10.4) at same time points,and burn group (31.9 ±6.7) at 72 h was signicantly higher than blast group (17.3 ± 6.3) (all P ＜ 0.05).Compared to control group,Calpain mRNA and protein expression in myocardial tissue were significantly increased in burn-blast group at all time points (all P ＜0.05).Calpain activity reached the peak at 24 h after injury,then gradually declined,and was significantly higher than control group (all P ＜ 0.05).Conclusion Calpain expression and activity increase in burn-blast combined injured rats which leads to myocardial damage.