一氧化氮对严重烫伤大鼠心功能的影响

目的 探讨一氧化氮（NO）对严重烫伤大鼠心功能的影响及其机制。方法 采用30％TBSAⅢ度烫伤模型，将90只SD大鼠随机分为5组，即烫伤对照组、假烫组、左旋精氨酸组（L－Arg)组、N－亚硝基左旋精氨酸甲酯（L－NAME）组和L－Arg L-NAME组，分别进行心功能参数和丙二醛及心肌摄钙测定。结果 与烫伤组比较，L－NAME组的平均动脉压、左室压峰值、左室内压最大上升／下降速率和心力环总面积可明显升高，而L－Arg组的以上参数却明显降低，L－Arg L-NAME组上述参数的变化无显著性意义。L－NAME组心肌丙二醛含量显著低于烫伤对照组，肌质网转运钙参数值却明显升高。结论 烧伤后大量产生的NO通过自身和其它自由基的细胞毒共同作用发挥其抑制心功能的效应，NO介导严重烫伤后的心功能下降与肌质网转运钙功能减弱有关。

Effects of nitric oxide (NO) on the cardiac function in severely scalded rats

OBJECTIVE: To investigate the effects of NO on the cardiac function in severely scalded rats and to elucidate its mechanism. METHODS: Ninety Sprague-Dawley (SD) rats inflicted with 30% TBSA III degree scalding were employed as the model and divided randomly into five groups, i.e. burn (B), shamburn (SB), L-arginine (L-Arg), N-nitroso-L-argininemethylester (L-NAME) and L-Arg + L-NAME groups. Cardiac functional indices, myocardial content of malondialdehyde (MDA) and myocardial Ca (calcium) transport were examined in the rats of all the groups, respectively. RESULTS: Compared to those in B group, the mean arterial pressure (MAP), left ventricular summit pressure (LVSP), the +/- dp/dt max in left ventricle pressure and the cardiac Lo in L-NAME group increased obviously. While those in L-Arg group decreased significantly but those in L-Arg + L-NAME group exhibited no remarkable change. The MDA content in L-NAME group was evidently lower than that in B group, while the calcium transport index of sarcoplasmic reticulum in L-NAME group increased obviously. CONCLUSION: Nitric oxide, massively produced postburn, exerted inhibitory effects on cardiac function by means of the cytotoxicity of its owns and other free radicals, which might be closely related to the decrease of its calcium transport function of sarcoplasmic reticulum.