| The majority of patients with type 2 diabetes mellitus in diabetic population and the most common cause of type2 diabetes is insulin resistance?IR?in the body.Existing drugs against insulin resistance?such as biguanides and thiazolidinediones?do not provide stable long-term control of blood glucose,and there are significant side effects.Therefore,finding new drugs that improve the IR state has important research and clinical significance.In recent years,fibroblast growth factor 1?FGF1?has been found to be an effective regulator of glycemic balance,regulating blood glucose,improving IR,but the mechanism of FGF1 improving insulin resistance needs further study.The aim of this study was to investigate the mechanism of action of insulin-sensitizing peptides FGF1,to improve insulin resistance by lowering blood glucose by three levels.At first,in terms of animal level,we studied the effect of recombinant human fibroblast growth factor 1?rhFGF1?on rapid hypoglycemia in a mouse model of type 2 diabetes with insulin resistance state.Secondly,at the cellular level,rhFGF1 was investigated for insulin resistance.At last,the effect of rhFGF1 on the expression of glucose transporter 1?GLUT1?and glucose regulated protein 78?GRP78?was studied at the molecular level,and preliminary study was carried out on the role of rhFGF1 in insulin sensitization mechanism.The main findings are as follows:1.By establishing two diabetes models,rhFGF1 has a good hypoglycemic effect on insulin resistance type2 diabetes mouse model in a short period of time.A mouse model of diabetic was established based on the STZ induction method.rhFGF1 had no effect on fasting blood glucose in healthy mice;the effect of single injection of hypoglycemic in hyperglycemic mice was not obvious.2 U·kg-1 insulin was screened to significantly reduce blood glucose,and rhFGF1 combined with hyperglycemia showed fasting Blood glucose levels were reduced in a dose-dependent manner.After a single injection of 1 mg·kg-1 rhFGF1,the fasting blood glucose of the spontaneous type 2 diabetic mouse model decreased significantly.Observing the pathological changes of pancreatic tissue,it was found that the cells in the hyperglycemia group showed apoptosis and rupture,and the cell boundaries were unclear,mostly scattered.After rhFGF1 treatment,the pathological findings were lighter and the IR status was improved.2.rhFGF1 is independent of insulin-inducing insulin-resistant HepG2 cells to take up glucose,which is dose-dependent and superior to pioglitazone and metformin.Insulin resistance cell model was established by treating HepG2 cells with 10-5 mol·L-1 insulin for 36 h.The optimal working concentration of the fluorescent glucose probe 2-NBDG was 10?mol·L-1 and the optimal time was 1 h.After 24 h of dosing,metformin,pioglitazone and rhFGF1 could increase the glucose uptake rate of IR cells to different degrees.The glucose uptake rate of the cells increased as the concentration of rhFGF1 increased.When the concentration of rhFGF1was 10-5 mol·L-1,IR cell glucose uptake rate is highest,and the glucose uptake was significantly higher than that of metformin and pioglitazone.3.GLUT1 labeled with red fluorescent protein?DsRed2?was transfected into C6 cells by plasmid transfection.The expression and distribution of GLUT1-DsRed2 after 5 h treatment with rhFGF1 by laser confocal technique.The expression distribution of GLUT1-DsRed2 in normal cells is roughly red-fluorescent and scattered throughout the cell.After treatment with rhFGF1,GLUT1-DsRed2 was concentrated on the surface of the cell membrane,and a small amount was distributed in the nucleus.4.GRP78 protein distribution accompanying intracellular transport of GLUT1 after rhFGF1 treatment showed translocation to the membrane by western blotting.After treatment with rhFGF1 for 30 min,the expression of GRP78 protein in cytoplasm was decreased and the cell membrane distribution was significantly up-regulated.It was concluded that rhFGF1 promoted the up-regulation of GRP78 expression and the change in distribution,consistent with the results of GLUT1-induced changes in rhFGF1-induced distribution,and involvement of external glucose into cells. |
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