Pancreatic Protein Expression In Type 2 Diabetic Rats By Sweet Corncob Polysaccharide

Diabetes is caused by a disorder of glucose metabolism in the human body.It is a state in which the body’s glucose metabolism and lipid metabolism are not properly regulated by insulin,which can cause fasting and postprandial blood glucose elevation.The main clinical feature is chronic hyperglycemia.Sweet corn cob polysaccharide（SCP-80-I）is a biologically active macromolecular substance extracted from sweet corn cob.At present,research has found that SCP-80-I has good biological activity in terms of anti-oxidation and hypoglycemia.However,the hypoglycemic mechanisms and targets of SCP-80-I remain to be studied.This study investigated the effects of SCP-80-I on insulin resistance in Hep G2 cells and the hypoglycemic effect of diabetic rats,and analyzed the hypoglycemic mechanism of SCP-80-I using TMT-labeled quantitative proteomics.The main research contents and results are as follows:First,treatment with 10^-6mol/L insulin for 24 hours was used to induce Hep G2 cells to form IR-Hep G2 cells.Second,the effects of SCP-80-I at different concentrations on glucose consumption,glucose metabolism,and antioxidant activity of IR-Hep G2 cells were investigated.The results show that each SCP-80-I can increase the glucose consumption of IR-Hep G2 cells,reaching the highest value when the concentration of SCP-80-I is 200μg/m L,and the subsequent concentrations of SCP-80-I are 200μg/m L.In addition,it was also found that glycogen synthesis in the SCP group increased by 25.06%,HK activity increased by 21.37%,and PK activity increased by 29.47%.MDA content decreased by 41.69%,and SOD activity increased by31.78%.It is suggested that SCP-80-I can regulate the metabolism of glucose by regulating the activity of HK and PK and the synthesis of glycogen,and it can improve the insulin resistance of Hep G2 cells by improving the antioxidant capacity and scavenging oxygen free radicals of IR-Hep G2 cells.Second,STZ-induced Wistar male rats were used to establish a diabetic rat model,and different doses of SCP-80-I were administered orally to evaluate its hypoglycemic effect.The results show that each group of SCP-80-I can improve the blood glucose,blood lipids,insulin levels and the swelling of the liver,kidney,heart and pancreas induced by STZ-induced diabetic rats,of which the high-dose SCP-80-I group is the best.In addition,by comparing the pancreas sections of the SCP-80-I group with diabetic rats,it was found that SCP-80-I can alleviate the morphological damage of pancreatic tissue in STZ-induced diabetic rats.It is preliminarily believed that its mechanism of action may be related to the repair of isletβcells and the process of improving blood lipid levels.Finally,using TMT-labeled quantitative proteomics technology to carry out research,a total of 4,780 proteins were identified,with a fold change greater than 1.5 times（upward adjustment greater than 1.5 times or down regulation less than 0.67 times）and p<0.05 in the normal group vs model group:A total of 551 differential proteins were detected,of which 366 protein expressions were up-regulated and 185 protein expressions were down-regulated;in the model group and the SCP-80-I gavage group:116 differential proteins were detected,of which 52proteins Expression was up-regulated and 164 proteins were down-regulated.The GO annotation function analysis was used to find the biological processes,cellular components,and molecular functions of the differential proteins.The KEGG pathway analysis was used to determine the signaling pathways of the differential proteins.Finally,the six differential proteins most relevant to the occurrence and treatment of diabetes were selected.The genes are:Pik3r5,Ndufb3,Pygl,Cbl,Prkcd,Stat1.In addition,research has also found that sweet corn cob polysaccharides can regulate oxidative phosphorylation pathways by down-regulating Ndufb3 activity,thereby affecting energy metabolism;regulating PI3K pathways by up-regulating pik3r5 gene expression,and thereby regulating insulin secretion;by regulating glycogen phosphorylase The inhibitory effect can regulate the metabolism of glycogen;inhibit the proinflammatory mediator to induce insulin resistance by up-regulating Cbl;reduce the blood glucose level by reducing the expression of protein kinase C;protect the pancreatic tissue from damage by inhibiting the expression of STAT1.It is also speculated that the SCP-80-I pathway may regulate glucose metabolism,insulin secretion and protect pancreatic tissues from damage through the PI3K-AKT and JAK-STAT signal pathways,thereby regulating blood sugar and reducing blood sugar.