热应激对兔慢性心力衰竭血浆NOS与血流动力学的实验研究

Experimental study of the effects of heat stress on NOS of plasma and hemodynamic in rabbits with chronic heart failure

目的 :探讨热应激对慢性心衰家兔血流动力学与血浆一氧化氮合成酶 (NOS)的影响。方法 :新西兰兔 2 5只作冠状动脉结扎 (CAL) ,另外 5只作对照 ,不作结扎为假手术组。冠脉结扎后 8周 ,CAL 组 2 5只兔随机分为常温对照组 (n=5 ) ,L- NAME组 (n=5 ) ,左旋精氨酸 (L- Are)组 (n=5 ) ,热应激组 (n=5 ) ,热应激 +左旋硝基精氨酸甲酯 (L-NAME)组 (n=5 ) ,并测定血流动力学、血浆 NOS。然后将动物放置在温度 4 2℃ ,待肛温达到 4 2℃ ,维持 15～ 2 0min,热应激结束后 ,将动物移到常温环境下 ,分别测定热应激终止后 2、4、8、2 4 h的血流动力学及血浆 NOS。结果 :1CAL 组血流动力学与假手术组比较差异非常显著 (P<0 .0 1)。2热应激组 2 4 h后血流动力学与对照组比较有改善 ;热应激 +L- NAME组血流动力学与对照组比较无改善 ;常温 +L- Arg组血流动力学与对照组比较有改善。 3CAL 组血浆 NOS比假手术组高 (P<0 .0 1)。结论 :热应激作用于慢性心衰后有保护心肌作用 ,改善血流动力学 ,其与升高的 NOS有关。

AIM:To investiagte the effects of heat strss on nitric oxide synthase of plasma and hemdynamic in rabbits with chronic heart failure. METHODS:coronary arteries of twenty-five rabbits were ligated(CAL), and thorax of five rabbits(sham group) were only operated on but not ligated. The 25 rabbits were divided into control group(n=5),L-NAME group(n=5), L-Arg group(n=5),heat stress(HS) group( n=5) , HS+ LNAME group( n=5) . Hemodynamic and NOS of plasma are examinated 8 weeks after CAL,then heat stress animals were placed in room where temperature about 42℃, and the animals will be taken out until recta temperature ofthe animals is about 42℃, and continous 15~20 min. Hemodynamic and NOS of plasma of heart failure animals were examinated 2, 4, 8,24 hours after heat stress. RESULTS:①Hemodynamic of CAL groups aredeteriorative than that of sham group follow 8 weeks ( P<0.01) . ②Hemodynamic of HS group were improved follow heat stress 24 hours(P<0.01). ③ NOS of plasma in CAL groups is higher than sham group 8 weeksafter CAL(P<0.01). ④ NOS of plasma in heat stress groups is elevated 24 hours after heat stress than those of control group and before heat stress(P<0.01). CONCLUSION:Heat stress influenced chronic heart failure can play a role of protecting myocardium and can improve hemodynanmic. That may be related to high NOS of plasma.