| Chronic hyperglycemia is the main characterized in Type II Diabetic Mellitus(TIIDM),which was caused by the relative or absolute lack of insulinand lead to metabolic syndrome of sugar, protein and fat metabolism dysfunction.TIIDM was often accompanied with a variety of chronic complications and also caused damage of multiple organ and system. Diabetes had become the second serious noninfectious chronic disease harmful to people’s health after the heart and brain vascular diseases. Raw banana powder(RBP) has good hypoglycemic material base,which is rich in resistant starch, pectin, soluble dietary fiber, flavonoids, polyphenols and other active ingredients.In this paper, researched the effective and improvement on hypoglycemic, glycolipid metabolism dysfunction and insulin resistance by animal models with type Ⅱ diabetic mellitus after RBP intervention,and explored the mechanism of insulin resistance from amino acid metabolism, insulin signal transduction pathway, Key enzymes and regulation factor in glycolipid metabolism signaling pathway. The main research results were as follows in this paper: 1. Improvement on glycolipid metabolism dysfunction in TIIDM rats after RBP intervention.(1) After intervention 8 weeks,the result showed that compared with diabetic control group, RBP intervention group rats weight increased 7.80%, food intake, water intake and urine volume reduced by 5.66%, 53.29% and 53.34%, and made hair shiny closer to normal rats, indicating that RBP intervention can significantly improve the state of polydipsia, polyphagia, polyuria and weight loss in Type II Diabetic Mellitus rats(2) RBP had certain regulation function of blood glucose, could reduce 32.75% fasting blood glucose, increased 74.12% glycogen content, and significantly reduced blood sugar peaks, stabilized blood sugar and improved glucose tolerance in Type II Diabetic Mellitus rats after RBP intervention.(3) After intervention 8 weeks,the result showed that compared with diabetic control group, high density lipoprotein cholesterol ratio(HDL-C/TCH) in serum of RBP group rats increased 86.96%, low density lipoprotein cholesterol(LDL-C), total cholesterol(TCH), triglyceride(TG), atherosclerosis index(AI) and free fatty acid(FFA) were reduced by 94.74%, 50.65%, 79.63%, 61.70% and 28.42%, which in serum LDL-C, TCH, TG and HDL-C/TCH level close to normal rats. It showed that RBP intervention could be used to correct the disorder of lipid metabolism in type Ⅱ diabetic rats.(4) RBP intervention could significantly reduced liver and body weight ratio and hepatomegalyin TIIDM rats, reduced the level of AST and ALT, improve the level of total protein(TP), globulin(GLB),AST/ALT and the A/G ratio in TIIDM rats. It indicated that, RBP had protection effect on liver injury in T2 DM rats by combined with liver biopsy 2. Improvement on insulin resistance in TIIDM rats after RBP interventionAfter intervention 8 weeks,the result showed that compared with diabetic control group, plasma fasting insulin decreased by 31.48%, C peptide levels and insulin clearance rate increased by 74.16% and 133.33% in RBP group rats, indicate that of RBP could improve hyperinsulinemia in type2 diabetes by increasing insulin clearance; RBP group rats HOMA- IRI decreased 105.24%,HOMA-ISI, HOMA-β,GLP-1 and pancreatic index were increased by 14.87%, 38.31%, 15.89% and 19.43%, protect islet cell damage in type Ⅱ diabetes mellitus rats by combined with pancreatic biopsy 3. Influence on amino acid metabolism of plasma in Type II Diabetic mellitus after RBP intervention.RBP intervention could significantly affect the locus of amino acid metabolism, and have a clear-cut recovery of amino acid metabolism of plasma in T2 DM rats. By significant analysis and trend analysis, discovered that had impact on changes trend of metabolism spectrum of plasma amino acid, and found a significant change of 12 kinds of amino acids in TIIDM rats after banana powder intervention, including glutamine, alanine, cysteine, β-alanine, arginine amino acids and color amino acid which levels have significantly improved and aspartic acid, valine, methionine, leucine, isoleucine and histidine which levels were significantly reduced. The results suggests that RBP had plays role of maintaining islet function and improving insulin resistance maybe through amino acid-m TOR-S6K1 signaling pathway. 4. Improvement and mechanisms of insulin resistance in the liver of db/db diabetes ratsPI3K/Akt signal transduction pathway: RBP intervention could up regulated m RNA expression of IR、IRS-2 in the liver of db/db diabetes rats, significantly down regulated m RNA expression of PI3K( p85) to activate PI3 K, and up regulated m RNA expression of Akt in PI3 K downstream signaling molecule, thus to improve insulin PI3K/Akt signal transduction pathway, improving insulin resistance; and RBP intervention could significantly up regulated m RNA expression of Gl UT2 in the liver of db/db diabetes rats and increasing glucose intake;m TOR-S6K1 signal pathway: RBP intervention could significantly down regulated m RNA expression of m TOR and S6K1 in the liver of db/db diabetes rats, inhibited m TOR-S6K1 signal pathway, thus to activate the insulin PI3K/Akt signal transduction pathways,thereby improved insulin resistance;Glucose metabolism pathway: RBP intervention could significantly down regulated m RNA expression of key regulatory factor Foxo1 and key enzyme PEPCK, CHREBP of gluconeogenesis and key enzymes GSK-3 of glycogen synthesis in the liver of db/db diabetes rats, thus promoted glucose uptake in the liver, increased glycogen synthesis, reduced gluconeogenesis and hepatic glucose output, thereby improved insulin sensitivity and reduced insulin resistance;Lipid metabolism signal pathway: RBP intervention could significantly down regulated m RNA expression of key regulatory factor PPAR-γ and key enzymes ACC and FAS of lipid metabolism in the liver of db/db diabetes rats, thereby reduced hepatic fatty acid synthesis and increased hepatic fatty acid oxidation, reduced lipid deposition in the liver, increased insulin sensitivity and improved insulin resistance;In summary,RBP improve insulin resistance may be by inhibiting diabetic db / db mice liver m TOR / S6K1 signaling pathway and restored insulin PI3 K / Akt signal transduction pathway, sugar metabolism and lipid metabolism signaling pathway, and revealed the mechanism of banana powder improved insulin resistance in the liver of db/db diabetes ratsin was a multi-channel, multi-target. 5. The hypoglycemic effect on db/db diabetes rats after RBP and RS.Raw banana powder and banana resistant starch(RS) had good improvement on the common symptoms,insulin resistance and pancreatic β-cell function, glucagon, GLP-1 and Amylin levels in db/db diabetic rat, but the effect of RBP was significantly superior than RS; Meanwhile, RBP could significantly reduce the level of blood glucose and Ghrelin,increased liver glycogen level and improved glycolipid metabolism dysfunction and hyperinsulinemia in db/db diabetic rat, but there was not obvious effect in RS.It showed that, RS played a role in RBP to improve insulin resistance, but other one or several components of RBP might be played a key role of hypoglycemic. The results suggested that the hypoglycemic effect of banana powder is not only the function of resistant starch, but also the result of the synergistic action of several components. |
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