Abstract: Objective To identify the effect of both high glucose and high insulin on miRNA-145 level was observed. Methods The human vascular smooth muscle cells (VSMCs) were cultured and the proliferation of VSMCs was induced by high glucose and high insulin medium. The samples were divided into 4 groups: normal group, high glucose group (25 mmol/L), high insulin group (300 mU/L), high glucose and high insulin group. The expression of miRNA-145 in VSMCs was assayed by real-time PCR. Proliferation of VSMCs was determined by MTT method After 72 h cultivation. The migration of VSMCs was analyzed by cell scratch test. VSMCs in each group was transfected by miRNA-145 virus (lentiviral vector). Proliferation and migration were assayed after 48 h transfection. Results Compared with normal group, the expression of miRNA-145 in VSMCs of other three groups was decreased (P<0.05), especially the expression in the high glucose and insulin group was the lowest (P<0.01). Proliferation and migration of VSMCs was promoted by high glucose and/or high insulin medium. Under fluorescent, transfection rate of VSMCs was about 80% after 48 h transfection. Proliferation and migration of VSMCs in each group after transfection were significantly lower than before (P<0.05). Conclusions High glucose and high insulin could decrease the expression of miRNA-145 in VSMCs, The overexpression of miRNA-145 could inhibit the proliferation and migration of VSMCs.

Key words: miRNA-145, vascular smooth muscle cells, diabetes mellitus