Regulation Of Sweet Corncob Polysaccharide On Signal Transduction Pathway In Type 2 Diabetic Mice

There are 463 million adults suffering from diabetes in the world,and about 90%of them are type 2 diabetes mellitus(T2DM).T2DM is a chronic disease requiring long-term medication,and currently widely used hypoglycemic drugs(such as biguanides,sulfonylureas)have different degrees of toxic and side effects,so looking for effective antidiabetic drugs with stable effect and low toxicity has become the focus of researchers in recent years.Sweet corn cob polysaccharide(SCP-80-I),isolated from sweet corn cob(SC),is a kind of non starch water-soluble polysaccharide with biological activity.In the current research,SCP-80-I shows stable hypoglycemic effect.In order to further clarify the molecular mechanism of the substance acting on diabetes model animals,the course first explores its effect on metabolism and tissue morphology of T2DM mice,and the results are as follows:T2DM model mice were established by high-fat diet combined with intraperitoneal injection of streptozotocin.After randomly divided into groups,normal saline,positive drug and different dose of SCP-80-I were given by gavage respectively.The blood glucose,hormone and tissue morphology of each group were determined.The results showed that SCP-80-I could regulate the blood glucose of mice to 10.9%±3.2 mmol/L,significantly reduced HOMA-IR,increased oral glucose tolerance(OGTT),and reduced serum leptin secretion to 0.43 ± 0.03 ng/ml,the secretion of adiponectin increased to 162.55 ± 8.03 ng/ml,which was significantly different from the model group;In addition,SCP-80-I had a positive effect on the morphology of pancreas and liver.Combined with the results of previous studies on the hypoglycemic and lipid-lowering effects of SCP-80-I on T2DM mice,AMPK and its related proteins in pancreatic insulin secretion and liver lipid metabolism pathway were selected as potential targets for research.Real time quantitative polymerase chain reaction(RT-PCR),transmission electron microscopy(TEM)and immunohistochemistry(IHC)were used to investigate the effects of SCP-80-I on several physiological processes in T2DM mice.The results showed that SCP-80I reduced the contents of TC,TG and LDL-C in serum to 2.84±0.06、0.90±0.04,1.85±0.05 mmol/L,respectively,increased HDL-C content to 2.39±0.13 mmol/L,which was significantly different from the model group.At the same time,the content of TC and TG in liver homogenate was decreased,and the liver glycogen was increased to 7.77 ± 0.23 mg/g,which was significantly higher than that of the model group.The deposition of amylin in pancreatic tissue was reduced by 30.86%,the apoptosis of islet cells was reduced by 13.29%,and the morphology of mitochondria was improved.In addition,SCP-80-I had significant effects on AMPK,ACC,CPT1 and PGC-1 α.The mRNA expression of AMPK and CPT1 in liver was up-regulated(p<0.01),and ACC was down regulated(p<0.01);The expression of AMPK,SERT1 and PGC-1α was up-regulated(p<0.01),and UCP2 was down regulated(p<0.01).In conclusion,SCP-80-I extracted from sweet corncob can reduce blood glucose and lipid levels in T2DM mice,improve the morphology of liver and pancreas,and promote the secretion of hypoglycemic hormone.Enhance liver glucose and lipid metabolism,reduce lipid deposition,reduce islets β Apoptosis,mitochondrial function and insulin secretion were improved.These physiological functions are related to the regulation of AMPK/ACC/CPT1 in liver and AMPK/SIRT1/PGC-1α and SIRT1/UCP2 signaling pathways in pancreas.The results of this study provide a possible idea for the molecular mechanism of sweet corn cob polysaccharide on the onset of type 2 diabetes,and provide a theoretical reference for the development and application of SCP-80-I.