Molecular Mechanisms Of Pumpkin Polysaccharides On Regulating Oxidative Stress Mediated Apoptosis Of Islet ? Cells

PPe?PPe-s-1 and PPe-s-2 were used as research objects to detect the antioxidant capacity in vitro and in vivo,aiming to explore the regulation mechanism of oxidative stress-related genes,to explore possible T2DM genes and analyze its chemical structures.Main results are as follows:1.The antioxidant activity and the ability of inhibit AGEs of PPe?PPe-s-1PPe-s-2 were determined by colorimetry.The results showed that PPe?PPe-s-1 and PPe-s-2 were able to improve the ABTS⁺·,scavenging of·O₂^-,reducing power and metal chelate ability significantly and which can inhibit the product of AGEs effectively,with apparent concentration dependent manner.2.INS-1 cells were used to study the antioxidant capacity of PPe?PPe-s-1 and PPe-s-2 in vitro.The results showed that PPe and PPe-s-2 could improve the oxidative damage of INS-1 cells induced by alloxan,delayed the cellular apoptosis under oxidative stress,and protected cells;PPe and PPe-s-2 can improve the mRNA expression of two key transcription factors PDX-1 and MafA,and PI3K/Akt/FOXO1signaling pathway in INS-1 cells under oxidative stress.3.C.elegans were used to study the anti-oxidation ability of PPe?PPe-s-1 and PPe-s-2 in vivo.RNA-Seq was used to study the genes of expression levels and differences of oxidative stress and glucose metabolism,which treatment by pumpkin polysaccharide and acid hydrolysate.The results showed that pumpkin polysaccharide and acid hydrolysate can alleviate the biofilm damage caused by oxidative stress,and the lifespan of nematodes after oxidative stress can be prolonged.PPe-s-1 and PPe-s-2 could increase the activity of SOD,CAT and GR,reduce the content of MDA and increase the content of GSH significantly.The differently expressed genes about 16 oxidative stress and 46 glucose metabolism were obtained by PPe-s-1 and negative control.The differently expressed genes about 9 oxidative stress and 10 glucose metabolism were obtained by PPe-s-2 and negative control.4.The molecular weight and structure of polysaccharide and acid hydrolysate were determined.The results demonstrated that the average molecular weights of PPe,PPe-s-1 and PPe-s-2 were 104.27 kDa,16.32 kDa and 0.73 kDa,respectively.In addition,PPe-s-1 and PPe-s-2 are composed of arabinose,rhamnose,glucose and galactose which molar ratios were 1.583:1.134:1.000:3.988 and 0.032:0.021:1.000:0.136,respectively.Further analysis showed that both PPe-s-1 and PPe-s-2 have branched side chains at the C1 position.Thus,it was speculated that the possible connection mode of PPe-s-1 is?-Rha?1?3?-?-Gal and the possible connection of PPe-s-2is?-Rha?1?3?-?-Gal.