Study On The Role And Mechanism Of H₂S In Exercise Intervention For Myocardial Fibrosis In Diabetic Rats

Research purpose:In this experiment,a 6-week-old male SD rat was fed a high-fat diet,and then a small dose of STZ was injected intraperitoneally to establish a type 2 diabetic rat model.After successful modeling,aerobic exercise intervention was performed.On the one hand,through HE and Masson staining observation of rat myocardial tissue and analysis of the immunohistochemical results of type?and?collagen fibers,we can understand the pathological changes of myocardial tissue fibrosis and explore the intervention effect of aerobic exercise on myocardial fibrosis On the other hand,by detecting changes in H₂S and Ang?/TGF-?1/Smad2 pathways in myocardial tissue,from the MMPs/TIMPs system,to explore the relationship between aerobic exercise,H₂S,Ang?/TGF-?1/Smad2 pathway Provide experimental basis for the study of the mechanism of exercise-mediated diabetes and complications.Research methods:In this study,Randomly divide male SD rats into two groups:the control group?NC group,n=10?normal diet,and the diabetes model group?DM group,n=30?high-fat diet.After 5 weeks of high-fat diet feeding,the DM group was injected with 1%STZ at a dose of 40mg/kg.One week later,blood was collected from the tail vein of the rat.If the fasting blood glucose was measured to exceed 7.8 mmol/L,the modeling was successful.After successful modeling,return to normal diet.The rats were divided into two groups,diabetes control group?DM group,n=7?,and diabetes exercise group?DME group,n=7?.In the DME group,there is no weight-bearing swimming training every day,6 days a week,60 minutes each time,a total of 8 weeks of training.After the last training of the rats,they were fasted for 12 hours.The next day they were anesthetized with a dose of 2.5ml/kg and intraperitoneal injection of 10%chloral hydrate,and then the blood was collected from the thoracic aorta and stored at-20°C for future testing.Part of the left ventricular myocardial tissue is placed in 4%formaldehyde solution,and the other part is put into liquid nitrogen,and stored in a refrigerator at-80°C.Results of the study:1)Compared with the NC group,the serum FBG and HOMA-IR of the DM group increased significantly?P<0.01?,while the serum INS content of the rat decreased,and there was no significant difference?P>0.05?;compared with the DM group In comparison,the serum FBG and HOMA-IR of the DME group were significantly reduced?P<0.05?,while the serum INS content of the rat was reduced,and there was no significant difference?P>0.05?;2)HE staining results showed:Under the microscope,the myocardial cells of the NC group were arranged neatly,with normal cell morphology,size and gap,and the nuclei were evenly distributed.The distribution of myocardial cells in the rats in the group was relatively smooth,and the cell morphology,size,and gaps were still normal.The results of MASSON staining showed that the interstitial blue staining area of the NC group was small,and no obvious fibrosis was observed.Obvious fibrosis?P<0.01?;the interstitial blue staining area of the DME group was reduced,and there was a little fibrosis change?P<0.01?;3)The semi-quantitative results showed that:compared with the NC group,the DM group myocardial tissue?Type III collagen fibers increased significantly?P<0.05?;Type III collagen fibers increased,but there was no significant difference?P>0.05?;Compared with DM group,DME group myocardial tissue type?,type III collagen fibers decreased,but No significant difference?P>0.05?;4)Compared with the NC group,the H₂S content in the myocardial tissue of the DM group was significantly reduced?P<0.01?;compared with the DM group,the H₂S content in the myocardial tissue of the DME group Very significant increase?P<0.01?;5)Compared with the NC group,the expression of TGF-?1,Smad2,TIMP2 protein in the myocardial tissue of the DM group increased,but there was no significant difference?P>0.05?,while the rats The expression of MMP2 protein in myocardial tissue decreased,and there was no significant difference?P>0.05?;compared with DM group,the expression of TGF-?1,Smad2,MMP2,TIMP2protein in myocardial tissue of DME group rats decreased,and there was no significant difference?P>0.05?;6)Compared with the NC group,the mRNA expression of TGF-?1,type III collagen fibers in the myocardial tissue of the DM group was significantly increased?P<0.05?,myocardial tissue Ang?,Smad2,?,Type collagen fibers,TIMP2mRNA expression increased,but no significant difference?P>0.05?,while MMP2mRNA expression decreased,there was no significant difference?P>0.05?;compared with DM group,DME group myocardial tissue The mRNA expression of TGF-?1,?,and?collagen fibers decreased significantly?P<0.01?,while the mRNA expression of Ang?,Smad2,MMP2,and TIMP2 all decreased,but there was no significant difference?P>0.05?.Conclusion:?1?In this experiment,a diabetes model was successfully constructed,and type?and type?collagen in myocardial tissue of diabetic rats increased significantly,indicating a certain degree of fibrosis.?2?Aerobic exercise can effectively prevent the development of diabetic myocardial fibrosis,and its mechanism may be related to the inhibition of H₂S on the Ang?/TGF-?1/Smad2 signaling pathway.