左旋精氨酸对冷暴露大鼠骨骼组织氧化应激酶系的影响

Effect of L-arginine on Oxidative stress enzymes in Rats Skeletal Muscles during Cold Exposure

目的研究补充左旋精氨酸(L-Arg)对冷暴露大鼠骨骼肌组织氧化应激酶系的影响,了解一氧化氮(NO)对冷暴露大鼠骨骼肌氧化应激酶系的调节作用。方法将88只大鼠分为3组:①对照组(8只);②冷暴露组(40只);③L-Arg+冷暴露组(40只)。冷暴露组和L-Arg+冷暴露组又分别分成5个小组,每组8只:分别于冷暴露1、3、7、14、21 d处死,对照级饲养7d处死。对照组于室温下饲养,冷暴露组和L-Arg+冷暴露组于(0±4)℃饲养1、3、7、14、21 d,L-Arg+冷暴露组大鼠每天给予L-Arg水溶液2 ml灌胃,相当于50 mg/kg的剂量。在冷暴露后各时间点取大鼠小腿骨骼肌组织检测丙二醛(MDA)含量和抗氧化酶活力:铜锌超氧化物歧化酶(CuZnSOD)、锰超氧化物歧化酶(MnSOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)。结果冷暴露组在冷暴露1～14 d时,大鼠骨骼肌组织中MDA含量明显高于对照组(P<0.05,P<0.01);在冷暴露21 d时恢复正常。L-Arg+冷暴露组在冷暴露1～7 d时明显高于对照组(P<0.01),在冷暴露1～3 d时明显高于冷暴露组(P<0.05,P<0.01),在冷暴露14d时恢复对照水平。CuZnSOD、MnSOD、CAT、GSH-Px的活力在冷暴露组从冷暴露第3天开始明显升高(P<0.05),除CuZnSOD活力在冷暴露14～21 d时恢复正常外,其他抗氧化酶活力在整个冷暴露期间均明显高于对照组(P<0.05,P<0.01)。而L-Arg+冷暴露组CuZnSOD、MnSOD、CAT、GSH-Px的活力在冷暴露1～21 d时均明显高于对照组和冷暴露组(P<0.05,P<0.01)。结论补充L-Arg能明显提高冷暴露过程中大鼠骨骼肌抗氧化防护能力,同时提示,NO对冷暴露大鼠骨骼肌氧化应激酶系有一定调节作用。

[Objective]To investigate the effect of L-arginine（L-Arg） on the oxidative stress enzymes in rats skeletal muscles during cold exposure,and understand the possible role of nitric oxide（NO） in the modulation of the oxidative stress enzymes in this tissue.[Methods]A total of 88 rats were randomly divided into 3 groups：① control group（8）,② cold exposure group（40）,③L-Arg＋ cold exposure group（40）.Cold exposure group and L-Arg＋cold exposure group were divided into respectively 5 subgroups with 8 rats in each which were killed respectively after 1,3,7,14,21 days cold exposure.The control group was killed after 7 days.The Control group was exposed to room temperature,while the cold exposure group and L-Arg＋cold exposure groups were exposed to（0±4） ℃ for 1,3,7,14,21 days.Each rat in L-Arg＋cold exposure groups was given 2 ml L-Arg solution（equivalent to 50 mg/kg） per day.The contents of malondialdehyde（MDA） and activity of antioxidant enzymes（CuZnSOD,MnSOD,CAT,GSH-Px） in the skeletal muscle were determined on day 1,3,7,14 and 21 of cold exposure.[Results]Comparing with control group,the level of MDA in cold exposure group was significantly higher after 1-14 days of cold exposure（P〈0.05,P〈0.01）;and recovery after 21 days of cold exposure.The level of MDA of L-Arg＋cold exposure group was significantly higher than that of control group（P〈0.01） after 1-7 days of cold exposure,and significantly higher than that of cold exposure group（P〈0.05,P〈0.01） after 1-3 days,and restored the control level after 14 days.In the cold exposure group,the activities of CuZnSOD,MnSOD,CAT and GSH-Px were increased significantly after 3 days（P〈0.05）;except for the recovery of CuZnSOD activity during 14-21 days of cold exposure,the other enzymes＇ activities were all significantly higher than that of control group during whole process of cold exposure（P〈0.05,P〈0.01）.While the activities of CuZnSOD,MnSOD,CAT,GSH-Px in L-Arg＋cold exposure group were all significantly higher than those of control group and cold exposure group during the whole cold exposure（P〈0.05,P〈0.01）.[Conclusion] L-Arg supplement can improve obviously the antioxidative defence in the rat skeletal muscles during cold exposure.These data also suggest the role of NO in the modulation of the oxidative stress enzymes in rats skeletal muscles during cold exposure.