Changes Of Free Amino Acids Of Rat Skeletal Muscle And Serum After EIMD

Objective: On the basis of EIMD model of rats downhill running, the purpose of this paper is to find the changes of free amino acids in muscle and serum at different times, and to find out the mutative free amino acids, so as to provide instructive suggestions for supplementing amino acids correctly,speed up skeletal muscle repair.Methods: 72 healthy male SD rats participate in the experiment. Rats were distributed into two groups: control group(C, n=8) and exercise group (E, n=64)(The exercise group included 0h group, 6h group,12h group,1d group,2d group,3d group,1w group and 2w group). In the experiment, all the rats did continuous downhill running once (the speed was 16m/min, the slope was -16°, the duration was 90 min).After running, serum was got from the inferior vena cava blood and right gastrocnemius were fetched for HE staining. The contents of free amino acids in skeletal muscle and serum were tested by HPLC. The images were collected and analyzed with optical microscope of Olympus DX70 and software of Image-Pro plus 4.1. Finally, data were analyzed by statistical software of SPSS 11.5.Results: (1) HE showed: pre-exercise skeletal muscle cells were normal. In 6h, there were some circular muscle fibers, suggesting swelling. Swelled cells increased gradually until the 1d. At 2d, there were some inflammatory cells. Most inflammatory cells were found at 3d, suggesting the most severity in skeletal muscle. (2) The contents of serum free amino acids showed: At 0h most amino acids declined, and after that, glutamic acid and phenylalanine kept declining until 6h. Isoleucine, leucine continued to decline to the lowest at 12h,other amino aids increased, and the peak point appeared at different time and in different frequency. Among them, threonine, valine, isoleucine, leucine peak appear once at 2d, aspartic acid, glutamic acid, arginine, lysine and proline appeared their peak at 1d, histidine and tryptophan appeared a peak at 12h, and then, tryptophan appeared another peak.Most of amino acids increased around 3d in serum. At 2w, all amino acids were slightly lower than pre-exercise. Aspartic acid, glutamic acid, histidine, isoleucine, lysine are significantly lower than pre-exercise (P <0.05). (3)At 0h, all amino acids were increased slightly, except threonine and arginine. Threonine and arginine were up at 1d,and tryptophan at 12h.Other amino acids reached a peak at 2d, most amino acids returned slightly higher than pre-exercise levels, but threonine, arginine, isoleucine were lower than pre-exercise levels.Conclusion: (1) Free amino acids in serum decline at 0h, probably because amino acids in the blood get into skeletal muscle to take part in metabolism. free amino acids in serum are upward around at 3d and free amino acids in skeletal muscle increase after 2d. It may be caused by further muscle damage, in which muscle degradation increase.(2)Changes of amino acids in serum and skeletal muscle appear that the condition essential amino acids change significantly, arginine and threonine has not been restored, suggesting that the supplement of these amino acids may promote the repair of skeletal muscle damage.