补充精氨酸对运动大鼠腹主动脉L-精氨酸/一氧化氮途径的影响

目的:探讨有氧运动和补充外源性L-精氨酸(L-Arg)对腹主动脉L-精氨酸/一氧化氮(NO)途径及NO代谢方式的影响。方法:将36只SD大鼠分为安静+生理盐水组、安静+L-Arg组、有氧运动+生理盐水组、有氧运动+L-Arg组。有氧运动组进行8周有氧运动训练;L-Arg组在每次运动前1小时左右按照500mg/kg体重的剂量给予L-Arg水溶液1ml灌胃;生理盐水组每天以同等剂量生理盐水灌胃。采用3H]-L-Arg同位素标记法测定腹主动脉壁L-Arg转运量、诱导型一氧化氮合酶(iNOS)活性;采用紫外分光光度计测定血清NO、抗超氧阴离子(抗)、超氧化物歧化酶(SOD)含量。结果:(1)与其它各组相比,有氧运动+生理盐水组大鼠腹主动脉L-Arg转运量和血清NO、抗含量显著下降(P<0.01),而组织iNOS活性显著上升(P<0.01);(2)两L-Arg组与其生理盐水对照组相比,L-Arg转运量和血清NO、SOD、抗含量均显著上升(P<0.01),iNOS活性稍有上升,但无统计学意义(P>0.05)。结论:(1)8周有氧运动后,腹主动脉L-Arg/NO途径中内源性L-Arg不足,iNOS活性异常上升,血清抗含量下降,NO含量减少。(2)运动前补充外源性L-Arg可明显抑制iNOS活性,提高抗含量,增加NO含量。

Effect of Supplementation of L-Arginine and Aerobic Exercise on the L-Arginine/Nitrogen Monoxidum Pathway in Abdominal Aorta of Rats

Objective The study was to investigate the effect of the aerobic exercise and supplement of L-Arginine (L-Arg)on the L-arginine/nitrogen monoxidum pathway in abdominal aorta in rats. Methods Thirty-six SD rats were randomly divided into four groups: supplementation of saline control group(AS),supplementation of L-arginine control group(AL),supplementation of saline and aerobic exercise group(SS),supplementation of L-arginine and aerobic exercise (SL). Intragastric administration of 1ml L-Arg solution with dose of 500mg/kg body weight 1 hour before aerobic exercise was performed in rats in supplementation groups and the control groups were administered intragastrically with the same volume of saline. Isotope labelling technique was used to measure the changes in L-Arg transport, induced nitricoxide synthase(iNOS)activity in abdominal aorta. Levels of nitric oxide(NO),superoxide dismutase(SOD) and anti-superoxide anion(anti- )in serum were also measured by ultraviolet spectrophotomete(rUV). Results(1)L-Arg transport and the levels of NO and anti- in group SS decreased significantly(P <0.01),but iNOS activity and the levels of SOD increased significantly(P<0.01)after aerobic exercise in group SL.(2)L-Arg transport and the levels of NO,SOD and anti-in groups AL and SL increased significantly after L-Arg supplementation(P<0.01),but the increase in group SL was more than in group AL. The iNOS activity in two groups increased slowly without significantly difference(P>0.05). Conclusions(1)8-week long-term aerobic exercise resulted in endogenous insufficiency of L-Arg, abnormally increased in iNOS,and the increased content of anti- ,leading to decreased levels of NO.(2) Supplementation of L-Arginine could inhibit the activity of iNOS obviously,reduce the generation of superoxide anion,and enhance the levels of NO.