Objective To explore the protective effects of dipeptidyl peptidase-4 inhibitor (DPP-4I) on AD-like neurodegenerative changes and its mechanism. Methods The human neuroblastoma cell line SH-SY5Y on the logarithmic phase was divided into six groups:control group (CON group, treated with PBS contained 1‰DMSO for 12 h), wortmannin intervention group (W group, treated with 0.03 μmol/L wortmannin for 12 h), DPP-4I intervention group (DPP-4I group, treated with 10μmol/L DPP-4I for 12 h), both DPP-4I and wortmannin intervention group (DPP-4I+W group, pre-treated with 10 μmol/L DPP-4I for 2 h, then 0.03 μmol/L wortmannin for 12 h), DPP-4I, wortmannin and Ex9-39 intervention group (DPP-4I+W+Ex9-39 group, pre-treated with 10μmol/L Ex9-39 for 2 h, then 10μmol/L DPP-4I for 2 h followed by 0.03μmol/L wortmannin for 12 h), and Ex9-39 intervention group (Ex9-39 group, treated with 10μmol/L Ex9-39 for 12 h). MTT assay was used to detect the cell vitality. Western blot assay was used to detect the level of total tau protein (tau-5) and phosphorylated tau at different sites (pSpS199/202, pT231 and pS396), the level of phosphorylated neurofilaments (NF-H, NF-M) and phosphorylation of critical enzyme in PI3K/Akt/GSK-3β signaling pathway. Results (1) The cell vitality decreased, the levels of pSpS199/202, pT231, pS396 and NF-H/M increased significantly in W group than those in CON group. However, comparing with CON group, the above mentioned parameters reversed in DPP-4I group. Comparing with W group, the cell vitality increased and phosphorylated levels of above mentioned indices were decreased in DPP-4I+W group. (2) The cell vitality showed a decline trend while the levels of phosphorylation tau at three different sites and NF-H/M were higher in Ex9-39 group than those in CON group. Comparing with DPP-4I+W group, the results of the phosphorylated levels showed the same changes in DPP-4I+W+Ex9-39 group. (3) Comparing with CON group, the expression levels of phosphorylated PI3K, Akt and GSK3β increased significantly in DPP-4I group, while those decreased in W group. Additionally, the expression levels of phosphorylated PI3K, Akt and GSK3β were significantly increased in DPP-4I+W group than those in W group. Conclusion DPP-4I can enhance the level of GLP-1 and activate PI3K/Akt/GSK-3βinsulin signaling pathway to improve the hyperphosphorylated tau and NFs induced by wortmannin, and to protect AD-like neurodegeneration.

Objective: To investigate the levels of vitamin D and the correlation between DPN and vitamin D in elderly patients with diabetic peripheral neuropathy(DPN). Methods: A total of 849 patients aged 60 years and over admitted into endocrinology department from June 2016 to September 2017 were enrolled in this retrospective case-control study.According to DPN diagnostic criteria, patients were divided into the non-DPN group(n=542)and the DPN group(n=307). The 25(OH)-vitamin D[25(OH)D]level and blood biochemical parameters were determined and compared between the two groups.The risk factors for DPN were analyzed using logistic regression analysis and plotting receiver operating characteristic(ROC)curves. Results: The mean of serum 25(OH)D level in the 849 patients was 43.9±19.4 nmol/L.Serum 25(OH)D level was lower in the DPN patients than in the non-DPN patients[(40.9±20.4)nmol/L vs.(45.7±18.6)nmol/L, P<0.05]. The incidence of 25(OH)D deficiency was higher in the DPN group than in the non-DPN group(72.3% or 222/307 vs. 64.6% or 350/542, P<0.05). Binary logistic regression analysis indicated that 25(OH)D was a protective factor for DPN(OR=0.980, 95% CI: 0.964~0.995, P<0.05)and the disease duration was a risk factor for DPN(OR=1.048, 95% CI: 1.027~1.070, P<0.001). ROC analysis indicated that the diagnostic cut-off value of serum 25(OH)D for predicting DPN was 37.5nmol/L, with a Youden index of 0.17, sensitivity of 0.65 and specificity of 0.52. Conclusions The 25(OH)D level is much lower in diabetic patients, especially in DPN patients.Higher 25(OH)VD level might be a protective factor for DPN, and vitamin D might be one of potential biomarkers for DPN in diabetic patients.

Objective To label granulocytes in a state of differentiation in mouse bone marrow (BM) with EdU (5-ethynyl-2′-deoxyuridine) for further understanding the changes in granulocyte produc-tion at different stages of differentiation during inflammation. Methods C57BL/6 mice were intraperitoneal-ly (i.p.) injected with EdU and heat-inactivated Escherichia coli(HI E.coli). BM cells were harvested at different time points after HI E.coli injection and then stained with fluorescent-conjugated antibodies(Abs). Myeloblasts,promyelocytes,myelocytes, metamyelocytes and band and segmented neutrophils were identi-fied by fluorescence-activated cell sorting(FACS). The percentage of EdU-positive cells in each population was recorded. Results The percentage of EdU-positive myeloblasts in mice increased by 10.0% at 24 h af-ter intraperitoneal injection with HI E.coli,but decreased by 75.0% and 23.0% at 48 h and 72 h,respec-tively. The percentage of EdU-positive promyelocytes declined by 23.0%,54.5%,64.3% and 77.8% at 24 h,48 h,72 h and 96 h,respectively. The percentage of EdU-positive myelocytes increased by 60.0% and 10.0% at 24 h and 48 h,but decreased by 80.0% and 90.0% at 72 h and 96 h. The percentage of EdU-positive metamyelocytes increased by 50.0% at 24 h,but decreased by 33.3%,61.5% and 66.7% at 48 h,72 h and 96 h. The percentage of EdU-positive band and segmented cells increased by 14.0% at 24 h,but decreased by 50.0%, 77.8% and 88.0% at 48 h, 72 h and 96 h. Conclusion Emergency granulopoiesis occurred 24 h after the establishment of HI E.coli-induced model of acute peritonitis, which meant that the proliferation of myeloid precursor cells,especially that of myelocytes and metamyelocytes,was accelerated and resulted in increasing number of mature neutrophils immigrating to sites of inflammation.