Objective To investigate the effect of DPP-4 inhibitor sitagliptin on atherosclerosis and its mechanism.Methods Thirty male ApoE-/-mice were randomly divided into two groups:experimental group(n=15) and control group(n=15).The mice in the experimental group were fed with high-fat mixture of sitagliptin and the control group was fed with high fat.Collected blood in the eyeballs in order to analyze serum levels of blood lipids and blood glucose after 16 weeks of feeding,and detected serum nitric oxide synthase(eNOS),vascular adhesion molecule-1(VCAM-1) with ELISA method.Collected aortic tissue in order to analyze atherosclerotic plaque.Results There was no significant difference in blood glucose,triglyceride and total cholesterol level between the two groups(P>0.05).The serum high density lipoprotein in the experimental group was significantly higher than that in the control group(P<0.05).The atherosclerotic plaque in the experimental group(7.55±1.87)%, which was significantly smaller than that in the control group(11.67±1.32)%.The serum VCAM-1 in the experimental group was lower and the eNOS was higher than that in the control group(P<0.05).Conclusion DPP-4 sitagliptin can increase the expression of HDL and eNOS and inhibit the expression of VCAM-1,thereby inhibiting the progression of atherosclerosis in ApoE-/-mice.

ObjectiveTo investigate the effect of mesenchymal stem cells （MSCs） combined with immunosuppressants （IS） on immune rejection in a rat model of liver transplantation. MethodsF344 rats were divided into Normal group （without any intervention）， PS group （injected with an equal volume of normal saline）， MSC group （injected with MSC）， IS group （injected with IS）， and MSC+IS group （injected with MSC and IS）， with 8 rats in each group. For all rats except those in the Normal group， the Kamada’s double-cuff method was used to establish a model of orthotopic liver transplantation， without reconstruction of the hepatic artery. HE staining and Masson staining were performed for rat liver tissue， and the degree of liver fibrosis was analyzed； immunohistochemical experiments were used to measure the infiltration of T cells and NK cells， and immunofluorescence assay was used to analyze macrophage M2 polarization. A one-way analysis of variance was used for comparison of continuous data between multiple groups， and the least significant difference t-test was used for further comparison between two groups. The Kaplan-Meier method was used to plot survival curves， and the log-rank test was used for survival analysis. ResultsCompared with the PS group， the MSC+IS group had a significantly prolonged survival time （P<0.01）， and the MSC group， the IS group， and the MSC+IS group had a significant improvement in the histological structure of the liver and a significant reduction in the degree of liver fibrosis （all P<0.000 1）， as well as a significant reduction in the infiltration of NK and T cells （all P<0.000 1） and a significant increase in the degree of macrophage M2 polarization （all P<0.000 1）. The MSC+IS group had a significantly better effect than the MSC group and the IS group. ConclusionMSCs combined with IS can improve liver histopathology， reduce inflammatory cell infiltration， promote macrophage M2 polarization， and exert an immunosuppressive effect in rats after liver transplantation.