Effects of aerobic exercise on renal function abnormalities and mitochondrial oxidative stress of obese rats
Objective To explore the effect of aerobic exercise on renal function abnormalities and mitochondrial oxidative stress of obese rats.Methods Ninety 5-week male Sprague-Dawley rats were randomly divided into a normal diet group(CON,n=10)and a high-fat diet group(n=80).The latter group was on high-fat diet for 8 weeks to induce obesity with renal function abnormality.After success-ful modelling,40 rats were chosen and randomly divided into a high-fat diet control group(HFD)and three groups of high-fat diet+aerobic exercise with different intensities(40%VO2max,60%VO2max,and 80%VO2max),each of 10.All exercise groups underwent daily 60-min aerobic exercise on treadmill,5 days per week for 4 weeks.After the intervention,their body weight,body length,perirenal and epi-didymal fat weights were measured,and morphometric indices including fat-body ratio and Lee's in-dex were calculated.Moreover,such biochemical indicators of renal function as serum creatinine(SCr),serum cystatin C and urinary microalbumin(mALB)were tested.Meanwhile,the pathological changes of the kidney were observed using hematoxylin eosin(HE)staining and Periodic acid-Schiff(PAS)staining,while the ultrastructural changes of the kidney and mitochondria were observed using the transmission electron microscopy.Moreover,the levels of superoxide dismutase(SOD),malondialde-hyde(MDA),and mitochondrial membrane potential in mitochondria were evaluated using ELISA kits.Results After 4 weeks of intervention,the average SCr,serum cystatin C,and mALB levels in the HFD group increased significantly compared with the CON group(P<0.05).Moreover,the average SCr levels of all exercise groups were significantly lower than the HFD group(P<0.05),with the average serum cystatin C and mALB levels of the 60%VO2max and 80%VO2max groups significantly lower than the HFD group(P<0.05).Meanwhile,the renal tubular epithelial cells in the HFD group showed mod-erate degeneration and increased glomerulosclerosis index(GSI)(P<0.05)and the degree of glomerular hypertrophy in each exercise group was significantly lower than the HFD group,with the renal tubules of the 60%VO2max group showing a clearer contour and decreased GSI(P<0.05).What's more,com-pared with the CON group,the number of swollen mitochondria in the HFD group increased,but the mitochondria damage of the 60%VO2max group relieved significantly compared with the HFD group.The renal mitochondrial MDA levels in the CON group increased significantly compared with the HFD group(P<0.05),and those of the exercise groups were significantly lower than the HFD group(P<0.05),with the most significant decrease in the 40%VO2max group(P<0.05).Moreover,the average renal mito-chondrial SOD and membrane potential levels in the HFD group decreased significantly compared with the CON group(P<0.05),while those in the 40%and the 60%VO2max groups were significantly higher than the HFD group(P<0.05).Conclusion Moderate to low intensity aerobic exercise can relieve renal dysfunction of obese rats by lowering the level of oxidative stress in renal mitochondria,mainly down-regulating such renal function biochemical indicators as SCr,serum cystatin C,and mALB,as well as alleviating the degree of renal tissue damage.
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维普
