吸入一氧化氮对烟雾吸入伤大鼠心脏的毒副作用

目的　评价吸入外源性一氧化氮 (NO)对烟雾吸入伤大鼠心脏的毒副作用。方法　 72只大鼠随机分为单纯吸氧组 (G1 ) (FiO2 0 40 ) ,低浓度NO吸入组 (G2 )和高浓度NO吸入组 (G3) ,G2 和G3除吸氧外 ,分别吸入 40 ppm和 80ppmNO ,每组分别与伤后 2、8、12、2 4小时检测血清中肌酸激酶 (CK)、肌酸激酶同工酶 (CK MB)、高铁血红蛋白 (MHb)、呼出气中NO2 浓度和心肌组织含水量 ,并进行光镜和电镜检查。另取 6只正常大鼠和 6只致伤后半小时大鼠测定伤前与伤后值作为对照。数据行多个样本均数间方差分析。结果　三组心肌含水量均高于伤前 (P <0 0 1) ,但三组间差别不显著。G3组呼出气中NO2 浓度明显高于G1 和G2 组 ;G1 组MHb明显高于G2 和G3组 (P <0 0 1) ;三组CK、CK MB均高于伤前值(G1 组P <0 0 1,G3组P <0 0 5 ) ,G2 组则明显低于G1 (P <0 0 1)和G3组 (P <0 0 5 ) ;G2 组心肌形态学和超微结构改变轻于G1 和G3组。结论　吸入 40ppmNO能明显改善吸入伤后大鼠心肌损害程度 ,对心脏有保护作用 ,80 ppm的NO对心肌存在一定损伤作用

Toxic and side effects of inhaling nitric oxide on the heart of rats with smoke inhalation injury

Objective To evaluate the toxic and side effect of exogenous nitric oxide (NO) on heart of rats with smoke inhalation injury.Methods 72 rats were divided into three groups rondomly,Group 1(G 1 n=24)was on oxygen inhalation(FiO 2 0 40); Group 2 (G 2 n=24) on low content of NO inhalation (40ppm);Group 3 (G 3 n=24) on high content of NO inhalation(80ppm).In additon,the last two groups were given oxygen inhalation at the same time.After 2,8,12 and 24 hours of the experiment,sera creatine phosphate kinase (CK),CK MB and MHb were determined respectively in each group,NO 2 contents in expiratory air and water content in cardiac muscles were measured.Cardiac muscle tissue from the three groups were examined with light and electron microscopy.6 animals without inhalation injury served as normal controls and another 6 animals subjected to inhalation injury were sacrificed at 30 minutes.ANOVA was used for multiple mean comparison.Results The water content in the cardiac muscle tissues of 3 groups were higher than in normal controls ( P< 0 01),but there was no difference among the 3 study groups.NO 2 content in expiratory air of G 3 was significantly higher than those in G 1 and G 2 ( P <0 05 and P< 0 01).MHb of G 1 was higher than those of G 2 and G 3( P< 0 01).CK ,CK MB of 3 groups were higher than that in normal controls (G 1 P <0 01; G 3 P <0 05;G 2 P >0 05),while these three parameters in G 2 were lower than G 1( P< 0 01) and G 3 ( P< 0 05).Moreover,morphological and ultrastructural alterations of cardiac muscle in G 2 were not as noticeble as those in G 1 and G 3.Conclusions Inhaling 40 ppm NO could reduce the pathological changes in cardiac muscle of rats injured with smoke inhalation,wheras 80 ppm NO might be harmful at varying degree to cardiac tissue of rats with inhalation injury.