| PurposeBy establishing a model of renal dysfunction in SD obese rats,detecting changes in the expression levels of key autophagy factors LC3,P62,Beclin1 m RNA and protein,as well as changes in blood and urine indicators and renal tissue structure,this study aims to explore whether different intensities of aerobic exercise can improve chronic renal dysfunction caused by obesity by activating autophagy,providing a basis for exercise and fitness for patients with chronic renal dysfunction caused by obesity.MethodsNinety sterile five week old male rats were selected for the experiment.After one week of adaptive feeding,the experimental rats were randomly divided into a regular diet group(n=10)and a high-fat diet group(n=80).The high-fat diet group induced the establishment of a chronic renal dysfunction model in obese rats.Eight weeks after modeling,a total of forty-nine rats in the high-fat diet group established a chronic renal dysfunction model.Forty successfully modeled rats with excellent athletic performance were randomly divided into a high-fat diet control group,a high-fat diet+40% VO2 max aerobic exercise group(40% VO2max),a high-fat diet+60% VO2 max aerobic exercise group(60% VO2max),and a high-fat diet+80% VO2 max aerobic exercise group(80% VO2max),with 10 rats each.Each exercise group received four weeks of aerobic exercise intervention with different intensities,five days per week for 60 minutes per day.After the last exercise intervention,rats were euthanized and sampled for 24 hours.Morphological indicators such as body weight,body length,perirenal and epididymal fat weight were measured,blood lipids and renal function biochemical indicators were detected.Renal tissue structural changes were observed using HE staining,PAS staining,and transmission electron microscopy.Autophagy related factors were detected using RT-q PCR and Western Blot.Results1.Morphological indicators: There was no significant change in the weight of the rats in the regular diet group,while the weight of the rats in the high-fat diet group showed a decreasing trend among the exercise groups.After four weeks,compared with the regular diet group,the high fat diet group showed a significant increase in body weight,fat to body ratio,perirenal and epididymal fat weight(P<0.01),and a significant increase in Lee’s index(P<0.05);The fat to body ratio,Lee’s index,and perirenal and epididymal fat weight increased in all exercise groups.Compared with the high-fat diet group,the 40% VO2 max group,60% VO2 max group(P<0.05),and 80% VO2 max group(P<0.01)showed significant weight loss;The fat to body ratio and Lee’s index of the 80% VO2 max group significantly decreased(P<0.05);The 40% VO2 max group and 80% VO2 max group showed a significant decrease in perirenal fat(P<0.05);The epididymal fat of each exercise group decreased significantly(P<0.01).There was no significant difference between the exercise groups.2.Blood lipid indicators: After four weeks,compared with the regular diet group,the high fat diet group(P<0.01),the 60% VO2 max group,and the 80% VO2 max group all had significantly higher levels of triglycerides and total cholesterol.Compared with the high-fat diet group,the 40% VO2 max group(P<0.01),60% VO2 max group,and 80% VO2 max group(P<0.05)showed a significant decrease in triglyceride levels;The total cholesterol levels in the 40% VO2 max group and 80% VO2 max group significantly decreased(P<0.05);The level of high-density lipoprotein cholesterol in 60% VO2 max group increased significantly(P<0.01);The 80% VO2 max group showed a significant decrease in low-density lipoprotein cholesterol levels(P<0.05).Compared with 40% VO2 max group,the level of high-density lipoprotein cholesterol in 60% VO2 max group increased significantly(P<0.01);The 80% VO2 max group showed a significant decrease in low-density lipoprotein cholesterol levels(P<0.05).3.Biochemical indicators of renal function: After four weeks,compared with the regular diet group,the high fat diet group showed a significant increase in serum creatinine and serum cystatin C levels(P<0.05);The level of microalbumin in urine increases;There were no significant changes in serum creatinine and cystatin C in each exercise group,while urinary microalbumin levels decreased.Compared with the highfat diet group,the serum creatinine levels in the 40% VO2 max group,60% VO2 max group(P<0.05),and 80% VO2 max group(P<0.01)were significantly reduced;The levels of serum cystatin C and urinary microalbumin were significantly reduced in the 60% VO2 max group and 80% VO2 max group(P<0.05).Compared with the 40% VO2 max group,the 60% VO2 max group and 80% VO2 max group showed a significant decrease in serum cystatin C(P<0.05).4.Renal tissue structural indicators:HE staining,PAS staining and transmission electron microscope: four weeks later,compared with the normal diet group,the renal tubular epithelial cells in the high-fat diet group showed mild to moderate degeneration, some renal interstitial blood vessels were dilated and congested,focal necrosis,and some glomeruli were slightly enlarged.At the same time,the number of round crosssection linear granules of renal tubules increased and swelled,the matrix and crista electron density decreased,and some mitochondrial matrices showed high electron density.Compared with the high-fat diet group,the degree of glomerular hypertrophy in each exercise group was reduced,with the 60% VO2 max group having clearer outlines of renal tubules and more regular glomerular morphology.Glomerular sclerosis index(GSI)and glomerular area: After four weeks,compared with the regular diet group,the high-fat diet group showed a significant increase in GSI(P<0.01)and glomerular area(P<0.05);GSI significantly increased in all exercise groups(P<0.01);The glomerular area increased in the 40% VO2 max group and 80% VO2 max group,while decreased in the 60% VO2 max group.Compared with the high-fat diet group,GSI in all exercise groups decreased significantly(P<0.05);The glomerular area of the 60% VO2 max group and the 80% VO2 max group decreased significantly(P<0.05).There was no significant difference between the exercise groups.5.Autophagy related factors:RT-q PCR: After four weeks,there were no differences in the expression of autophagy related factors Beclin-1,Lc3,and P62 m RNA among the groups.Western Blot: After four weeks,compared with the regular diet group,the high fat diet group,40% VO2 max group,and 60% VO2 max group showed increased expression of Beclin1 and LC3 proteins,while the expression of P62 protein decreased;The 80% VO2 max group showed a decrease.Compared with the high-fat diet group,the 40% VO2 max and 60% VO2 max groups showed an increase in protein expression of Beclin1 and LC3,while the expression of P62 protein decreased;The 80% VO2 max group showed a decrease.There was no significant difference between the exercise groups.Conclusions1.Three different intensities of aerobic exercise can reduce body weight,fat to body ratio,Lee’s index,and perirenal and epididymal fat in obese rats.Among them,80% VO2 max aerobic exercise intensity is more effective in reducing body weight.Three different intensities of aerobic exercise can improve the blood lipid status of obese rats with chronic renal dysfunction.Among them,60% VO2 max aerobic exercise intensity is more effective in increasing high-density lipoprotein cholesterol.2.Three different intensities of aerobic exercise can reduce serum creatinine,serum cystatin C,and urinary microalbumin levels in obese rats,with 60% VO2 max aerobic exercise intensity being more effective in improving urinary microalbumin levels.3.Three different intensities of aerobic exercise can reduce glomerulosclerosis and restore glomerular area,among which 60% VO2 max aerobic exercise intensity is more effective in improving renal structural abnormalities in obese rats.4.40% VO2 max and 60% VO2 max aerobic exercise intensity can increase the expression levels of Beclin1 and LC3 proteins,and reduce the expression levels of P62 proteins,indicating the activation of autophagy levels in renal cells and improving chronic renal dysfunction.5.Based on comprehensive analysis of morphology,blood lipids,renal function biochemistry,renal structure,and autophagy related indicators,60% VO2 max aerobic exercise intensity has the best effect on improving chronic renal dysfunction caused by obesity. |
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