谷氨酰胺对大鼠运动性疲劳的改善作用及其机制

Effects of glutamine on exercise-induced fatigue,skeletal muscle oxidation and liver cell apoptosis in rats

目的:探讨谷氨酰胺(Gln)对大鼠运动性疲劳、骨骼肌氧化应激和肝脏细胞凋亡的改善作用。方法:将8周龄SPF级雄性SD大鼠20只,体重180~220 g,适应性喂养1周后随机分为对照组和谷氨酰胺干预组,每组10只。谷氨酰胺干预组采用每天1.0 g/kg/d谷氨酰胺灌胃(约2 ml),对照组以等体积生理盐水灌胃(约2 ml),持续7 d。随后进行力竭实验,禁食不禁水12 h后处死大鼠,检测血清及骨骼肌谷胱甘肽(GSH)和丙二醛(MDA)水平及超氧化物歧化酶(SOD)活力,检测血清乳酸(LD)水平及肌酸激酶(CK)和乳酸脱氢酶(LDH)活力;荧光实时定量PCR检测肝组织Bcl-2和Bax基因表达水平。结果:与对照组相比,谷氨酰胺干预组大鼠力竭时间显著延长(P<0.05),血清CK、LDH及LD水平显著降低(P<0.05),血清与骨骼肌中GSH和SOD水平显著提高(P<0.05),MDA水平明显降低(P<0.05);肝组织Bax基因表达水平显著降低(P<0.05),Bcl-2基因表达水平明显显著增高(P<0.05)。结论:谷氨酰胺有缓解大鼠运动性疲劳的作用,其机制可能与降低骨骼肌氧化应激程度和延缓肝脏细胞凋亡率有关。

Objective:To investigate the effects of glutamine on exercise-induced fatigue,skeletal muscle oxidation and liver cell apoptosis in rats.Methods:Twenty SPF grade SD rats aged at 8 week and weight from 180 to 220 g,were divided into control group and glutamine-treated group after one week of feeding,10 rats in each group.The rats in the glutamine group were treated with glutamine at the dose of 1.0 g/(kg·d)by intragastric administration,and the rats in control group were administrated with equal volume of normal saline.After 7 days,the exhaustion test was conducted,the content of glutathione(GSH)was detected by high-performance liquid chromatography.Superoxide dismutase(SOD),malondialdehyde(MDA),lactic acid 2-hydroxypropanoic acid(LD)were detected by enzyme-linked immunosorbent assay,and the creatine kinase(CK)was detected by electroluminescence.Activities of CK,Lactate dehydrogenase(LDH),and expression levels of Bcl-2 and Bax mRNA were detected by fluorescence quantitative RT-PCR.Results:The duration of exhaustion in the glutamine group was greater than that in the control group(P<0.05).The serum glutathione level in the glutamine group was lower than that in the control group(P<0.05).After exhaustion,the levels of GSH,SOD and MDA in serum and skeletal muscle of the glutamine group were higher than those of the control group significantly differences(P<0.05).The serum Bax mRNA level in the glutamine group was lower than that in the control group significantly(P<0.05).The serum bcl-2 mRNA level in the glutamine group was higher than that in the control group significantly(P<0.05).Conclusion:Glutamine can effectively alleviate exercise-induced fatigue in rats,reduce the oxidation degree of skeletal muscle,and decrease the apoptosis rate of liver cells.