Abstract:

Abstract:Objective To discuss the relationships between  the serum creatine kinase (CK),lactate dehydrogenase (LDH) and skeletal muscle injury in rats after different load movement and to provide a theoretical basis for study on muscle injury with scientific and accurate judgement.Methods 70 Wistar male rats were divided into non-exercisegroup (control group), a bout of eccentric exercise group(AE) and 7 d  eccentric movement group(SE).Gastrocnemius were taken immediately，24 h and 7 d aftera bout of eccentric exercise or the last exercise, respectively.The changes of tissue structure and serumCK,LDH,malondialdehyde(MAD) and superoxide dismutase(SOD) activities were observed.Results The tissue structure of skeletal muscle of rats in AE group was damaged seriously  24 h after a bout of eccentric exercise;the tissue structure in SE group was also damaged seriously in the immediate time at the last exercise,showing the muscle fiber distortion, shrinkage,disappearance of cross striations and other changes.The activities of serum CK,LDH and MDA reached the peak in the immediate time after exercise in AE group,there were significant differences compared with control group  (P<0.001).The activity of serum SOD was increased significantly 24 h after exercise in AE groups compared with control group  (P<0.001).The activities of serum CK,LDH,MDA,and SOD in SE group were significantly increased in the immediate time  after the last exercise,and the differences between SE group and control group were significant (P<0.001).Conclusion The activities of serum CK,LDH and MAD of rats appears time course changes,and it is not consistent with the skeletal muscle tissue damage,and the changes of skeletal muscle injury has a certain delay phenomenon.The activity peaks of  serum CK,LDH,MAD,and SOD 7 d after eccentric exercise  are consistent with the skeletal muscle injury.LDH can be the indirect index to evaluate the repair degree of the skeletal muscle injury after eccentric exercise.

Key words: eccentric exercise；skeletal muscle injury；tissue structure； creatine kinase； lactate dehydrogenase