Correlation Between ³¹P-MRS With Desmin Expression In Skeletal Muscle Of SD Mice After Exhaustive Swimming

ObjectiveTo evaluate the correlation between metabolic changes in ³¹P-MRS and Desmin expression in skeletal muscle of SD mice after exhaustive swimming.Methods45 SD male mice were randomized into 3 groups:control group,half exhaustive swimming group and exhaustive swimming group.³¹P-MRS(Gyroscan intera 1.5T MR, Philips) were performed in right lower limb under anesthesia.MRS observation indexes included the peak areas of Pi,PCr,ATP and the ratios of Pi/PCr,Pi/ATP,PCr/ATR The morphological changes were confirmed by histopathology,and immunohistochemical method(SP)were taken for the assessment of Desmin expression with optical density(OD).Results(1)Control group:Peak areas of Pi,PCr,ATP are 0.16±0.05,1.33±0.62,0.41±0.06,ratios of Pi/PCr,Pi/ATP,PCr/ATP are 0.14±0.08,0.39±0.13,3.28±1.62. Both morphology and arrangement of skeletal muscle cells were regular under microscope and OD was0.55±0.04.(2)Half exhaustive swimming group:Peak areas of Pi,PCr,ATP are 0.33±0.16,0.90±0.20,0.79±0.35,ratios of Pi/PCr,Pi/ATP,PCr/ATP are 0.40±0.17,0.54±0.40,1.48±1.09.The disorder arrangement of skeletal muscle cells with edema and filaments separate were found under microscope,OD was 0.32±0.01.(3)Exhaustive swimming group:Peak areas of Pi,PCr,ATP are 0.49±0.21,0.52±0.09,0.19±0.07,ratios of Pi/PCr,Pi/ATP,PCr/ATP are 0.99±0.45,3.08±1.88,3.15±1.33,part of muscle filaments breakdown and atrophy were found under microscope,OD was 0.21±0.02.(4) The peak areas of Pi,PCr,ATP and the ratio of Pi/PCr were at a high level of significance among three groups.The correlation coefficients of Pi,PCr,ATP,Pi/PCr,Pi/ATP were 0.621(P=0.000),0.775(P＜0.001),0.127(P=0.01),-0.75(P=0.000)and 0.583(P=0.001),respectively.There was no significance between PCr/ATP and OD value(r=0.205,P=0.276).Conclusions³¹p-MRS could quantitatively reflect the SD mice exercise-induced injury after exhaustive exercise,which corresponding to morphological changes and histological structure damages,the peak area of PCr and the ratio of Pi/PCr which could evaluate the degree of injury,also be taken as indexes of exercise-induced injury.