氨基胍和L-精氨酸对内毒素性肺损伤大鼠肺脏线粒体损伤的影响

Effect of aminoguanidine and L-arginine on mitochondria injury in acute lung injury rats induced by endotoxin

目的观察选择性诱生型一氧化氮合酶(iNOS)抑制剂氨基胍(aminoguanidine,AG)和一氧化氮供体L-精氨酸(L-arginine,L-Arg)对急性肺损伤大鼠肺脏线粒体功能的影响,并探讨其改善急性肺损伤的作用机制。方法将雄性SD大鼠随机分为对照组、急性肺损伤模型组(模型组)、AG治疗组(AG组)、AG+L-Arg治疗组(AG+L-Arg组)、L-Arg治疗组(L-Arg组),采用舌静脉注射内毒素脂多糖(lipopolysaccharide,LPS)复制大鼠急性肺损伤模型,大鼠急性肺损伤3 h后,给药治疗3 h,断头放血处死,迅速取出大鼠肺脏,匀浆器混匀后,离心提取肺脏组织线粒体,测定线粒体总ATP酶、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、总一氧化氮合酶(T-NOS)、iNOS、结构型一氧化氮合酶(cNOS)的活性,以及线粒体肿胀度、膜流动性和线粒体一氧化氮(NO)、丙二醛(MDA)含量。结果大鼠内毒素性急性肺损伤后,肺脏组织中线粒体表现为肿胀、膜流动性降低,线粒体中的T-NOS和iNOS活性显著升高(P<0.05或<0.01),线粒体NO生成明显增加(P<0.05或<0.01),而cNOS活性无明显变化(P>0.05);线粒体总ATP酶、SOD、GSH-Px活性均明显下降(P<0.05或<0.01),线粒体MDA含量明显升高(P<0.05或<0.01)。急性肺损伤3 h给予不同药治疗3 h与急性肺损伤组比较,一氧化氮合酶(NOS)活性、NO生成有所变化(P<0.05或<0.01),总ATP酶、SOD、GSH-Px活性均显著升高(P<0.05或<0.01),MDA含量明显下降(P<0.05或<0.01)。结论AG和L-Arg能够通过抑制肺线粒体中iNOS活性,增强eNOS活性,改变NO的产生,对抗LPS诱导的肺损伤,有效的保护肺组织。

Objective To investigate the effect of aminoguanidine and L-arginine（L-Arg）on mitochondria injury in acute lung injury rats induced by LPS. Methods The rats were randomly divided into control group, acute lung injury group, AG group （model group）, AG＋ L-Arg group, and L-Arg group. The model of acute lung injury was prepared with injection of LPS in rats. Different drugs were respectively administrated through intraperitioneal injection 3 h after the injury induced by LPS, and rats were killed and the mitochondria of lungs was isolated by differential speed centrifugation. The activities of T-NOS, iNOS, ATPase, SOD and GSH-Px, the contents of NO and MDA in mitochondria were respectively measured. Results The activities of T-NOS and iNOS were significantly increased（ P 〈 0.05 or 〈 0.01）, the activities of ATPase, SOD and GSH-Px were significantly decreased too（ P 〈 0.05 or 〈0.01）, and the contents of NO and MDA were increased after acute lung injury （ P 〈 0.05 or 〈 0.01 ）. Conclusion Aminoguanidine and L-arginine can inhibit effectively the activity of iNOS, enhance the activity of eNOS, improve mitochondria energy pump, change the production of NO, relieve oxidative injury, so that which can effectively protect lung tissue against acute lung injury induced by LPS.