[Involvement of microRNA-145/TGF-β in the regulation of swimming exercise on vascular calcification in type 2 diabetic rats].

The present study aimed to explore the effect of swimming exercise on vascular calcification in type 2 diabetic rats and its related molecular mechanism. Male Sprague Dawley (SD) rats were randomly divided into normal control (NC), diabetes control (DC) and diabetes+exercise (DE) groups. The DC and DE groups were intraperitoneally injected with streptozotocin (STZ) and fed with high-fat diet to establish type 2 diabetes mellitus model. The NC and DC groups did not exercise, and the DE group performed swimming exercise for 8 weeks. ELISA was used to detect the serum glycated hemoglobin A1c (HbA1c) level. The aortas of rats were taken as sample. Assay kits were used to detect vascular calcium content and alkaline phosphatase (ALP) activity. Von Kossa staining was used to detect calcium deposition. qRT-PCR was used detect the expression of microRNA-145 (miR-145). Western blot was used to detect the protein expression levels of smooth muscle contraction markers, calcification marker and related proteins. The results showed that, compared with the NC group, the blood glucose, serum HbA1c level, vascular calcium content and ALP activity in the DC group were significantly increased, the protein expression levels of smooth muscle contraction markers smooth muscle protein 22α (SM22α) and α-smooth muscle actin (α-SMA) were significantly down-regulated, and the protein expression level of calcification marker osteopontin (OPN) was significantly up-regulated; Compared with the DC group, the serum HbA1c level, vascular calcium content and ALP activity in the DE group were significantly decreased, the protein expression levels of SM22α and α-SMA were significantly up-regulated, and the protein expression level of OPN was significantly down-regulated; Compared with the NC group, the expression of miR-145-5p in the DC group was significantly down-regulated, and the protein expression levels of transforming growth factor-β (TGF-β), SMAD2, ERK1/2 and p-ERK1/2 were significantly up-regulated; Compared with the DC group, the expression of miR-145-5p was significantly up-regulated in the DE group, while the expressions of TGF-β, ERK1/2 and p-ERK1/2 were significantly down-regulated. These results suggest that miR-145/TGF-β signaling is involved in the improving effects of 8-week swimming exercise on glucose metabolism disorder, vascular smooth muscle cell phenotype switching and vascular calcification in type 2 diabetes mellitus.