| Objective:To establish a rat model of type 2 diabetes mellitus(T2DM)by high-sugar and high-fat diet combined with injection of streptozotocin(STZ),and to apply different intensity of exercise intervention during model establishment to explore its role in type 2 diabetes.The effect of modeling rate,serum TNF-α content and expression of MMP-9/TIMP-1 protein in kidney tissue were observed.Methods:50 Sprague Dauley(SD),divided into five groups:the control group(N).the diabetes model(DM),the small-intensity exercise intervention group(LE),the moderate-intensity exercise intervention group(ME),the high-intensity exercise intervention group(HE),and 5 groups of 10 per group.Group N was fed with normal feed,group DM was fed with high-sugar and high-fat diet,and all were freely active in cages;group LE,ME,and HE were fed with high-sugar and high-fat diets,and different stages of treadmill exercise were performed during the period.At the end of the 8th week,after measuring the body weight and fasting blood glucose(FBG)of each group of rats,the rats were fasted for 12 hours overnight,and group N was given intraperitoneal injection of citrate buffer,and group DM,LE,ME,and HE were injected intraperitoneally 2%STZ solution.The body weight and FBG of each group were measured on the 7th day after STZ injection,and the OGTT experiment was performed to compare the area under the curve(AUCFBG).The concentration of serum tumor necrosis factor(TNF-α)and glycated serum protein(GSP)in each group was determined by eyelid blood sampling.Taking kidney tissues.Part of the rats were embedded in paraffin,stained with HE.and the morphology of the kidney was observed under light microscope.The diameter of the glomeruli was measured.Partial homogenization and Western blotting(WB)were used to detect the expression of matrix metalloproteinase-9(MMP-9)and its inhibitor(TIMP-1)in kidney tissue.Result:1、There was no significant difference in initial body weight(P>0.05).At the end of the 8th week,the body weight of group DM was significantly higher than that of group N(P<0.05);the weight of group LE,ME,and HE was not significantly different from that of group N(P>0.05),while the weight of group HE was significantly lower than that of group DM,LE,and ME(P<0.05).On the 7th day after STZ injection,the weight of group HE was significantly lower than that of group N,DM.LE and ME(P<0.05).There was no significant difference in body weight between groups N,DM,LE and ME(P>0.05);compared with the 8th week,there was no significant change in body weight of group N and group ME on the 7th day after injection(P>0.05),while the body weight of group DM,LE and HE decreased significantly(P<0.05).2、Effects of different intensity exercises on glucose metabolism.2.1 There was no significant difference in FBG between the initial and the 8th week(P>0.05).On the 7th day after STZ injection,the FBG of group DM,LE,ME and HE was significantly higher than that of group N(P<0.05);the FBG of group ME and HE was significantly lower than the DM and LE groups(P<0.05).Compared with the 8th week,the FBG of the DM,LE,ME,and HE groups on the 7th day of STZ injection was significantly increased(P<0.05),and there was no significant change in the N group(P>0.05).2.2 On the 7th day after injection of STZ,the GSP content of each group was detected.Compared with group N,GSP in group DM,LE and HE was significantly increased(P<0.05),and there was no significant difference in group ME(P>0.05).Compared with group DM,there was a significant decrease in GSP in group ME(P<0.05),and there was no significant difference in group LE and HE;there was no significant difference between groups LE,ME and HE(P>0.05).2.3 The AUCFBG of rats in group DM,LE,ME and HE were significantly higher than those in group N(P<0.05).There was no significant difference between groups DM and LE(P>0.05).The AUCFBG in group ME was significantly lower than that in groups DM and LE(P<0.05);The AUCFBG in group HE was significantly lower than groups DM and LE(P<0.05);there was no significant difference between groups ME and HE(P>0.05).3、At the end of the 7th day of STZ injection,the rat tail vein blood was taken to detect random blood glucose to determine the mold formation rate of each group.The modulus of DM,LE,ME and HE were significantly higher than that of group N(P<0.05);There was no significant difference between the LE and ME groups(P>0.05);the HE composition rate was significantly lower than that of the DM group(P<0.05).4、Effects of Different Intensity Exercises on Morphological Structure of Kidney.4.1 HE staining showed that the kidney structure of group N was clear and intact with no obvious pathological changes.In the DM group.the glomerular structure of the kidney was unclear,the glomerular hypertrophy,the basement membrane thickened,the mesangial area widened,and the number of glomerular cells increased.In the LE group,the kidney glomerular hypertrophy,the mesangial area was broadened,and the number of glomerular cells increased.Renal tubules and glomerular injury were significantly alleviated in ME and HE groups,glomeruli were not significantly hypertrophied,and the number of glomerular cells was decreased.4.2 The glomerular diameter measurement showed that compared with group N.the glomerular diameter of group DM and group LE increased significantly(P<0.05),and there was no significant difference between group ME and E(P>0.05);Compared with group DM,the glomerular diameter of group ME and HE was significantly decreased(P<0.05),and there was no significant difference between group LE(P>0.05).Compared with group LE,the glomerular diameter of group ME and group HE decreased significantly.(P<0.05);there was no significant difference between the ME and HE groups(P>0.05).5、The levels of serum TNF-α in group ME and group HE were significantly lower than those in groups N,DM and LE(P<0.05).There was no significant difference between groups N,DM and LE(P>0.05).There was no significant difference between the ME and HE groups(P>0.05).6、There was no statistical difference in the expression of MMP-9/TIMP-1 protein between the two groups.Conclusion:1、During the 8-week high-sugar-high-fat diet combined with low-dose STZ to construct the T2DM rat model,the body weight,FBG,GSP,and AUCFBG of the different intensity exercise intervention groups were improved compared with the diabetic model.Moderate and high-intensity exercise interventions can more effectively regulate T2DM blood glucose levels and improve glucose tolerance,while high-intensity exercise intervention can more effectively reduce the rate of T2DM.2、During the 8-week high-sugar and high-fat diet combined with low-dose STZ to construct a T2DM rat model,moderate-intensity and high-intensity exercise interventions can slow renal structural changes and reduce serum TNF-α levels,but on renal tissue MMP-9/TIMP-1 protein has no effect. |
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