Study On Screening Of Antidiabetic Probiotics And Their Function

Diabetes Mellitus(DM)is a metabolic disorder resulting from many factors and characterized by chronic elevated blood sugar.The ever-increasing prevalence of diabetes has been one of the biggest health challenges in the world.And many studies have confirmed the usefulness of probiotics in the prevention and therapy of diabetes.Therefore,the present study was designed to screen for potential probiotics based on high alpha-glucosidase and dipeptidyl peptidase-IV inhibitory activity,and their beneficial effects for diabetes were evaluated in vivo.In addition,explore the impact of probiotics on intestinal microflora abundance and diversity,which provides a theoretical basis for the study of probiotics to improve the intestinal microbiota of diabetes.77 probiotic strains were screened for potential probiotics based on high alpha-glucosidase and dipeptidyl peptidase-IV inhibitory activity from cell-free excretory supernatants(CFS)and cell-free extracts(CFE).Meanwhile,probiotic properties such as tolerance to the low pH,simulated saliva(SS),simulated gastric juice(SGJ),simulated intestinal juice(SIJ),transporting,bile salts tolerance as well as adhesion to HT-29 cell assays were also examined.And the principal component analysis(PCA)showed that the strain BLP12 that have high alpha-glucosidase inhibitation and the strain ST-2 that have high dipeptidyl peptidase-IV inhibitation displayed the best combination characteristics.Type 2 diabetic mice model were successfully established by feeding with high-fat diet and injecting with low-dose of STZ.The model was used to evaluate preventive and therapeutic effects of the strain BLP12 and ST-2.The results showed that the strain BLP12 and ST-2 significantly decreased fasting blood glucose and improved oral glucose tolerance.Furthermore,they decreased the values of glycosylated hemoglobin(HbA1c),pro-inflammatory cytokines and blood lipid,and increased the levels of glycogen and Anti-inflammatory cytokines.Additionally,these two strains significantly improved oxidation indicators and protected the islets of Langerhans.And the strain BLP12 and ST-2 decreased the expressions of glucose-dependent insulinotropic polypeptide(GIP)mRNAs of the caecum in diabetic mice.The effects of the strain BLP12 and ST-2 on intestinal microbiota in type II diabetic mice were analyzed and studied by MiSeq high-throughput sequencing.The results showed that the diversity of intestinal microbiota in normal mice was higher than that in type 2 diabetic mice induced by STZ.And the species diversity and richness of intestinal microbiota in diabetic mice were changed.In the phylum,a significant decrease in Proteobacteria was observed in the BLP12 and ST-2 group compared with the control.And in the class,the strain BLP12 and ST-2 significantly decreased the level of Lachnospiraceae and Leuconostocaceae,and increased Lactobacillaceae.Furthermore,in the probiotics group compared with the control,the number of bacteria increased significantly in Lactobacillus,but decreased significantly in Desulfovibrio,Alistipesl and Intestinimonas.Finally,after the analysis of non-metric multidimensional scaling,the result showed that the intestinal flora of diabetic mice has been adjusted and improved,and the difference with the normal group is decreasing.