| Objective:To explore the effect of DPP4 on aortic calcification in diabetic mice and its possible mechanism.Methods:The 60 male C57 mice were randomly divided into 6 groups: control group,diabetic calcification group,Sitagliptin group,PD98059 group,BAY 117082 group,PD + BAY group,Each group of mice were fed with high-sugar and high-fat fodder.After 4 weeks of feeding,a type 1 diabetic mouse model was established(intraperitoneal injection chain ureurelin STZ).Random blood glucose of mice was measured continuously after injection of STZ.Random intravenous blood glucose concentration of mice was more than 16.7 mmol/L for three consecutive times,which indicated that the model was successful and the mice whose blood glucose did not reach the standard could be given a small dose of STZ again.The blank control group was fed with high-sugar and high-fat diet,the DPP4 inhibitor group was fed with high-sugar and high-fat + sitagliptin(200 mg/kg/d)diet,and the ERK inhibitor group was given high-sugar and high-fat diet + intraperitoneal injection.PD98059(10mg/kg/d),NF-κB inhibitor group was given high glucose and high fat diet + intraperitoneal injection of BAY117082(5mg/kg,three times a week),ERK+NF-κB inhibitor group was given high sugar and high fat diet + Intraperitoneal injection of PD98059 and BAY117082,The body weight and blood glucose concentration of the mice were measured weekly and recorded,and continuously tested for 4 weeks,4 weeks later,the concentration of DPP4 in mice was detected by ELISA kits.Calcium ion kit was used to determine the aorta calcium ion content.The abdominal aortic calcification in each group was determined by VONKOSSA calcification staining.The expression conditions of ERK1/2 、 NF-κB 、RUNX2、OPG、OPN protein in vascular tissue were determined by immunohistochemistry and Western blot.Results:The blood glucose of the mice with diabetes was significantly higher than that of the control group,and the difference was statistically significant(P<0.05).Compared with control group,the concentrations of aorta calcium ion and DPP4 were significantly higher in diabetic mice group(P<0.05).Compared with diabetic mice group,the concentrations of aorta calcium ion and DPP4 were significantly decreased in sitagliptin group and different inhibitors groups(P<0.05).In VONKOSSA calcification staining in aortic arteries of mice,the aortic black calcium salt silver staining particles in the type 1 diabetes group were significantly deposited,and black calcium appeared in the sitagliptin group,PD98059 group,Bay117082 group and PD98059+BAY117082 group.Salt silver stained granules,but significantly reduced(P<0.05)compared with black calcified silver stained granules in diabetic calcification group.HE staining showed vascular tissue disorder and elastic fiber rupture in the diabetic calcification group.The vascular tissue disorder and the elastic fiber rupture were significantly reduced in the sitagliptin group,PD98059 group,Bay117082 group and PD98059+BAY117082 group(P<0.05).In immunohistochemistry,both ERK and NF-κB proteins were expressed in tissues of diabetic mice.Compared with diabetic mice group,the expression levels of ERK and NF-κB protein were decreased in sitagliptin group,PD98059 group,Bay117082 group and PD98059+BAY117082 group.In Western blot quantitative experiments,the expression levels of p-ERK and NF-κB protein were significantly increased in diabetic mice group compared with those in control group(P<0.05).Compared with diabetic mice group,the expression levels of p-ERK and NF-κB protein were significantly decreased in sitagliptin group,PD98059 group,Bay117082 group and PD98059+BAY117082 group(P<0.05).Conclusions:Serum DPP4 concentration increased in diabetic mice.Sigliptin,a DPP4 inhibitor,could inhibit aortic calcification in diabetic mice.The possible mechanism of aortic calcification in diabetic mice is that DPP4 promotes aortic calcification by activating ERK1/2 and NF-kappa B signaling pathways. |
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