Abstract: Objective To investigate the effects and mechanism of high glucose on the osteopontin (OPN) expression in rat aortic vascular smooth muscle cells (VSMCs). Methods SD rats were intraperitoneally injected with streptozotocin, OPN and PCNA expression in rat thoracic aortas were detected by immunohistochemical staining, RT-PCR and western blot analysis; After primary rat aortic VSMCs treated with DMEM medium supplemented with normal glucose (5.5mmol/L), high glucose (25mmol/L), mannitol (25mmol/L), high glucose + GF109203X (PKC inhibitor, 10μmol/L) and high glucose + NAC (N-acetyl-l-cysteine, NF-κB inhibitor, 10μmol/L) for 48 h, OPN expression was examined by immunofluorescence and western blot, expression of PCNA, PKC, and p65 were assessed by western blot analysis. Results OPN and PCNA expression were increased in hyperglycemic rat aortic VSMCs. Expression of OPN, PCNA, PKC, and p65 were significantly up-regulated in VSMCs exposed to high glucose. Expression of PCNA was attenuated by GF109203X and NAC in high glucose-treated VSMCs, while the expression of OPN was only inhibited by GF109203X. Conclusion High glucose induces OPN expression and cell proliferation in VSMCs may be due to the activation of PKC signal, which play a critical role in diabetic vascular complications.

Key words: vascular smooth muscle cells, high glucose, osteopontin, PKC, NF-κB