Effects Of Aerobic Exercise Combined With Ala-Gln On The Formation Of NAFLD In Type 2 Diabetic Rats And Its Mechanism

Objective:(1)To explore the intervention and interaction of aerobic exercise and Ala-Gln on formation of fatty liver in type 2 diabetes mellitus.(2)Fromthe changes of SREBP-lc/Cidea pathway and its related miRNA in liver tissue,the biological mechanism of exercise and Ala-Gln intervention in fatty liver formation of T2DM was explored.Method:10 rats were randomly selected rats as normal control group(Control,NC=10)from 804-week-old male SD rats,did not exercise training,fed a standard normal diet.The remaining 70 rats were fed a high fat diet.Six weeks later,in an empty stomach,injected low-dose streptozotocin according to 40 mg/kg,seven days to keep feeding,tail vein blood,blood sugar levels more than 11.1mol/L or diabetes mice model success.And then the type 2 diabetes rats were randomly divided into 4 groups:DM control group(DMC,n=10),DM+aerobic exercise training group(DME,n=10),DM+Ala-Gln group(DMAG,n=10),DM+aerobic exercise training+Ala-Gln group(DMEAG,n=10).The DM did not exercise training and feed standard normal diet;Exercise were used 60 minutes unloaded swimming for 8 weeks,6 times per week;Ala-Gin were irrigationed after the end of each training 30min,the supply of 1.5 g/Kg weight,6 times per week.8 weeks later,the serum FBG,INS,TG,TC,LDL,ALT,GLP-1 contents in every groups were examined,the expression of SREBP-lc,Cidea mRNA,miR-122,miR-34a in liver tissue were examined in each group ofrats,MDA,GSH contents in liver tissue and the morphology and ultrastructure of liver tissue were observed.Results:(1)Compared with NC group,in DMC group,the contents of FBG,LDL and serum ALT activity increased significantly(P<0.05),the content of INS,TG and TC increased,but there were no significant(P>0.05),GLP-1 contents decreased significantly(P<0.01).Through the double factor variance analysis,aerobic exercise could decrease the rates FBG,TG,LDL significantly(P<0.01),serum INS,GLP-1 contents increased,but no significant(P>0.05);the effect of Ala-Gln control on T2DM rates FBG(P<0.05)decreased significantly,TG,TC,LDL contents decreased significantly.serum INS,GLP-1 increased significantly(P<0.05);the effect of aerobic exercise and Ala-Gln control on T2DM rates to increase the serum INS contents had significantly obvious interaction(P<0.01),but decreased FBG,TG,TC,LDL contents had no significantly obvious interaction(P>0.05).(2)Under light microscope and electron microscope,compared with the NC group,DMC group showed varying degrees of fat vacuolar degeneration,partial hepatic lobule disorder,and hepatic sinus narrowing.In DME group,lipid vacuoles appear in rat liver cells,and the disorder of liver cells line becomes lighter.The degree of steatosis was significantly decreased in the DMAG group,and the hepatocyte structure became normal.Compared with DME and DAG rats,the DMEAG rats had more obvious improvement in their Liver tissue morphology.The hepatocyte sinusoids tend to be normal but a small amount of lipid droplets were still visible.The activity of ALT in serum of DMC rats was significantly increased(P<0.05),Aerobic exercise did not significantly increase the activity of ALT in serum of T2DM rats,supplementation with Ala-Gln could significantly reduce the activity of ALT(P<0.01),Aerobic exercise combined with Ala-Gln had no significant interaction with the decrease of serum ALT activity(P>0.05).(3)Conlpared withNC grounp,DMC grovp rats liver tissue the expression of SREBP-lc(P<0.05)Cidea mRNfA,miR-34a(P<0.01),increased significantly,miR-122 decreased significantly(P<0.01).Throughthe double factor variance analysis,aerobic exercise could decrease the T2DM rats liver tissue the expression of Cidea mRNA,miR-34a significantly(P<0.01),SREBP-1c decreased,but no significantly(P>0.05),miR-122 increased significantly.the effect of Ala-Gln control on T2DM rats liver tissue could the expression of SREBP-1c,miR-34a decrease significantly(P<0.01),Cidea mRNA decreased but no but no significantly(P>0.05).The effect of aerobic exercise and Ala-Gln control on T2DM rates to decrease the Cidea mRNA,miR-34a and increase miR-122 had no significantly obvious interaction(P>0.05),however,there was a significant interaction between reducing liver SREBP-lc mRNA expression(P<0.05).(4)Cormpared with NC group,DMC group liver tissue MDA content increased significantly(P<0.05),content of GSH decreased significantly(P<0.01);Through the double factor variance analysis,aerobic exercise could decrease the T2DM liver tissue MDA significantly(P<0.05),increased GSH significantly(P<0.01);the effect of Ala-Gln control on T2DM liver tissue MDA contents decreased significantly(P<0.05),GSH contents increased significantly(P<0.01);the effect of aerobic exercise and Ala-Gln control on T2DM rates to the MDA,GSH had no significantly obvious interaction(P>0.05).Conclusion:(1)The T2DM rat model replicated in this study was successful.Simple aerobic exercise or Ala-Gln supplementation can promote insulin secretion and reduce FBG in T2DM rats,while aerobic exercise combined with Ala-Gln have no significant additive effective effect on reducing FBG.(2)Eight weeks after successful mode ling,T2DM rats showed some lipid deposition in the liver,which formed fatty liver,and to some extent non-alcoholic steatohepatitis.While aerobic exercise and Ala-Gln supplementation can effectively inhibit the formation of fatty liver in T2DM rats,and to some extent,Aerobic exercise combined with Ala-Gln is better than pure aerobic exercise or Ala-Gn supplementation.(3)The expression of miR-34a in liver tissue of T2DM rats increased,and miR-122 decreased,and the accumulation of fat in the liver was accelerated by targeted activation of the SREBP-lc/Cidea signaling pathwy.This is the main mechanism of non-alcoholic fatty liver formation in T2DM rats.Aerobic exercise and Ala-Gln supplementation can inhibit the hepatic SREBP-1c/Cidea signaling pathway,thereby reducing the deposition of hepatic TG and effectively preventing the formation of fatty liver.(4)With the development of T2DM,oxidative stress in liver tissue increased significantly,while aerobic exercise and Ala-Gln supplementation can significantly improve liver oxidative stress,thus preventing the formation of fatty liver.