氨基胍等对严重烧伤大鼠一氧化氮表达及烧伤休克的影响

目的:研究一氧化氮合酶(NOS)抑制剂与严重烧伤大鼠体内NO产量、NOS表达以及平均动脉压(MAP)变化的关系。方法:复制大鼠重症烧伤模型,检测应用非选择性NOS抑制剂L-NAME和选择性诱生型NOS(iNOS)抑制剂氨基胍(AG)后大鼠血液中NO代谢产物(NO₂^-／NO₃^-)以及肺和十二指肠组织中神经型NOS(nNOS)mRNA的表达水平,同时测定各组大鼠的MAP。结果:烧伤后大鼠血液中NO₂^-／NO₃^-含量显著增高,L-NAME和AG都能抑制NO₂^-／NO₃^-的升高,P<0.01;烧伤后nNOS的mRNA表达在肺和十二指肠中均有不同程度升高,AG和L-NAME使nNOS表达增加,L-NAME作用更为显著,P<0.01;烧伤后大鼠MAP略有上升,然后进行性下降,L-NAME组大鼠MAP显著升高,但于3h后急剧下降,AG组大鼠MAP下降速度明显低于对照组。结论:结构型NOS(cNOS)与iNOS在烧伤休克病理生理过程中的作用明显不同,iNOS活性过度增高与烧伤休克发病关系密切。

Effects of nitric oxide inhibitors on NO mRNA expression and burn shock in rats with thermal injury

AIM: To identify the effects of nitric oxide synthase (NOS) inhibitor on NO production, expression of NOS and mean artery pressure (MAP) in rats with severe burns. METHODS: After administration of non-selective NOS inhibitor, L-NAME, and selective inducible NOS (iNOS) inhibitor, aminoguanidine (AG), to rats with severe burns, levels of NO - 2/NO - 3 in blood, mRNA expression of nerve NOS (nNOS) in lung and duodenum, MAP in each group were calculated. RESULTS: Levels of NO - 2/NO - 3 in blood of rats increased significantly post burn, which could be inhibited by L-NAME and AG, especially by L-NAME. Expression of nNOS mRNA in lung and duodenum of rats increased post burn, which could be enhanced by AG and L-NAME. MAP of rats decreased gradually post burn and administration of AG could slow down this process significantly. CONCLUSION: cNOS and iNOS could play different roles in the pathophysiology of burn shock. Over-expression of iNOS could be closely related to the pathogenesis of burn shock.