| Objective: The goal of this research was to investigate the effects of the dipeptidylpeptidase-4inhibitor,sitagliptin on the protein expressin of vascular cell adhesionmolecule-1(VCAM-1) and intercellular adhesionmolecule-1(ICAM-1) and the serumlevel of stromal cell derived factor-1α(SDF-1α) in apolipoprotein E geneknockout(Apoe-/-) atherosclerosis mice model,and to explore direct action and the partpossible mechanism of sitgliptin improves on the atherosclerotic lesions.Method:1.The establishment of the atherosclerosis model:(1)Apoe-/-mice（n=61）wereallowed to adjust to their new environment for one week, and then randomized into twoeither a normal diet group(n=13) or an model group(n=48) according to the weight.Thenormal diet group mice were fed with a astandard diet until the end of the experiment.The atherosclerosis mice model were established by feeding a high-fat diet for12weeks.(2)After feeding for12weeks, selected6mice respectively from normal dietgroup and model group.The pathological changes of mice aortas were observed underlight microscope after HE staining. The atherosclerosis model was established afterobtering atherosclerotic plaque was formed in model mice by HE staining.2.Groups and treatment: When atherosclerosis model was established, the modelgroup animals randomly assigned to six groups(n=7): higt-fat diet group(control group);atorvastatin group: mice were given high-fat diet and drinking water with atorvastatin(10mg/kg/d); sitagliptin small dose group: higt fat diet and drinking water withsitagliptin(50mg/kg/d); sitagliptin large dose group: higt fat diet and drinking water withsitagliptin(200mg/kg/d); atorvastatin combined sitagliptin small dose group:high-fat dietand drinking water with atorvastatin(10mg/kg/d) and sitagliptin(50mg/kg/d);atorvastatin combined sitagliptin large dose group: higt fat diet withatorvastatin(10mg/kg/d) and sitagliptin(200mg/kg/d). The normal diet group mice fed with a astandard diet as a vehicle group.The animal were given dringking water with orwithout drug for6weeks.3.Detection indexes and measures:(1)weights and blood glucose:detece the weightand blood glucose once a week.(2) blood lipid,serum insulin and SDF-1α: Serum levelsof total cholesterol, triacylglycerols, LDL-cholesterol, insulin and SDF-1α weremeasured at the end of6weeks treatment. Mice were fasted for12h, blood wascollected from the retro-orbital sinus.Serum was centrifugaled and storde at-20untilanalysis.Serum TG and TC were measured by enzymatic determination.LDL-C wasmeasured by selective precipitation method.Serum insulin and SDF-1α were detected byEnzyme Linked ImmunoSorbent Assay(ELISA).(3)HE staining: At the end of6weeksintervention, detecting the pathological changes of vascular intima and atheroscleroticplaque each group by HE staining.(4)Western blot: The protein expressin of ICAM-1and VCAM-1were measured by Western blot in mice aortic after6weeks intervention.Results:1.HE staining of aortic arch show there were no marked difference between thedrug intervention groups and higt-fat diet group.2. There was no notable difference between the drug intervention groups andhigt-fat diet group in weight after6weeks (p=0.708).3. There was no marked difference in blood glucose and the level of serum insulinbetween each group after6weeks involved(p=0.421, p=0.345).4. Blood lipid: LDL-C:The drug intervention groups were lower than higt-fat dietgroup,there was statistically significant difference between sitagliptin small dose group,sitagliptin large dose group, atorvastatin combined sitagliptin small dose group andhigt-fat diet group(p=0.02；p=0.002；p=0.01); sitagliptin intervention and combinedintervention groups were lower than atorvastatin group, and there was statisticallysignificant difference between sitagliptin large dose group, atorvastatin combinedsitagliptin small dose group and atorvastatin group(p=0.011；p=0.044). There was nodifference between each group after6weeks drug intervention(p=0.938). TG and TC:There was no difference between higt-fat diet group and drug interventiongroups(p>0.05).5.Western blot analysis:①VCAM-1:Atorvastatin add sitagliptin small dose group was less than others,and no difference between normal diet group(p=0.57). sitagliptin small dose group and atorvastatin combined sitagliptin small dose groupwere effectively reduced compared with the higt-fat diet group or atorvastatin gro up(p<0.01).The sitagliptin small dose group was obviously lower than sitagliptinlarge dose group(p<0.01); atorvastatin combined sitagliptin small dose group was noticeably lower than atorvastatin combined sitagliptin large dose group(p<0.01).②ICAM-1: Atorvastatin combined sitagliptin small dose group was less than normal diet group(p=0.014). Drug intervention groups were obviously lower comparedwith the higt-fat diet group(p<0.01). The sitagliptin small dose group and atorvastatin combined sitagliptin small dose group were lower than atorvastatin group,but the difference was insignificant between sitagliptin small dose group and atorvastatin group(p=0.144);There was a significant difference between atorvastatin combined sitagliptin small dose group and sitagliptin small dose group(p<0.01). Thesitagliptin small dose group was obviously lower than sitagliptin large dose group(p=0.037); atorvastatin combined sitagliptin small dose group was noticeably lower than atorvastatin combined sitagliptin large dose group(p<0.01).6.The level of serum SDF-1α had no marked difference among each group(p=0.894）。.Conclusion:1.The study demonstrated that the effect of sitagliptin on atherosclerosis in Apoe-/-mice was independent on the mice weight，blood glucose and the level of serum insulin.2. Sitagliptin reduce the level of LDL-C in Apoe-/-atherosclerosis mice,anddecrease risk factor of cardiovascular disease.3. Small dose of sitagliptin could significantly reduce the expression of VCAM-1and ICAM-1in the Apoe-/-atherosclerosis mice, and the effects of combination withatrovastatin were more obvious.4. Compared with small dose of sitagliptin/combined with atorvastatin, large doseof sitagliptin/combined with atorvastatin could significantly increased the expressin ofVCAM-1and ICAM-1in Apoe-/-atherosclerosis mice.5. Compared with higt-fat diet group, different doses of sitagliptin increase theserum level of SDF-1α,but atorvastatin decrease the serum level of SDF-1α; Comparedwith different doses of sitagliptin intervention, atorvastatin combined with the samedosage of sitagliptin decrease the serum level of SDF-1α.Therefore, small dose of sitagliptin could significantly reduce the expression ofVCAM-1and ICAM-1in the Apoe-/-atherosclerosis mice, and blocking the progress ofAS by reduce inflammatory. It shows the opposite tendency for the dose of sitagliptinon the expression of VCAM-1and ICAM-1.The effect could relecvant to the increase of the serum level of SDF-1α which caused by the inhibitory activity of sitagliptin onDPP-4. |
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