(School of Physical Education,South China Normal University,Guangzhou 510006,China) Abstract: In order to observe the changing of and relationship between the myocardial inflammatory injury and CD8+ T lymphocyte expression of rats exercising with an incremental load, and to probe into the function of laser therapy of different intensities on protecting a heat undergoing a high intensity exercise, the authors divided 8-week old male SD rats randomly into a control group (C) consisting of 54 rats, and an experiment group consisting of 54 rats, including a low intensity laser + exercise group (LE), a high intensity laser + exercise group (HE), and an exer-cise group (E), each of which consisted of 18 rats, sampled the rats in the groups in weeks 2, 4 and 6 respectively, evaluated their heart coefficients, overall heart shapes, myocardial pathological scores, apoptosis of myocardial CD8+T lymphocytes and cardiocytes, and revealed the following findings: as compared with the rats in group C, the rats in group E in week 6 showed significant cardiocytes inflammatory infiltrating, myocardial fibers twisting, swelling and rupturing, a significantly different pathological score (P<0.01), increased serum TNF-α, myocardial CD8+T lymphocytes filtrating, and a very significantly increased cardiocyte apoptosis index; as compared with the rats in group E in the same period (week 2, 4 or 6), the rats in group LE had slightly lighter myocardial inflamma-tion; in week 6, the numbers of apoptosis of CD8+T lymphocytes and cardiocytes increased as compared with those of the rats in group C, yet decreased significantly as compared with those of the rats in group E (P<0.01). The said findings indicate that laser therapy can, to a certain extent, alleviate myocardial inflammatory infiltration and in-flammatory factors, reduce the degree of myocardial pathology, and restrain the process of apoptosis of cardiocytes. Key words: sports medicine;myocardial inflammatory injury;exercising with an incremental load;low intensity laser;CD8+T lymphocyte;rats |