Tetramethylpyrazine protects against high glucose-induced vascular smooth muscle cell injury through inhibiting the phosphorylation of JNK, p38MAPK, and ERK

OBJECTIVES: High glucose-induced alterations in vascular smooth muscle cell behavior have not been fully characterized. We explored the protective mechanism of tetramethylpyrazine (TMP) on rat smooth muscle cell injury induced by high glucose via the mitogen-activated protein kinase (MAPK) signaling pathway. METHODS: Vascular smooth muscle cells (VSMCs) isolated from rat thoracic aortas were divided into control, high glucose (HG), and pre-hatching TMP groups. The effect of different glucose concentrations on cell viability and on the migration activity of VSMC cells was examined using MTT analysis and the wound scratch assay, respectively. Superoxide dismutase (SOD) and malondialdehyde (MDA) levels were measured using enzyme-linked immunoassays. The levels of extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38MAPK, and MAPK phosphorylation were assessed by western blotting. RESULTS: Cell proliferation was remarkably increased by increased glucose concentrations. Compared with the HG group, the migratory ability of VSMC cells was reduced in the presence of TMP. TMP also decreased the MDA content in the supernatant, but significantly increased the SOD activity. Western blotting showed that TMP inhibited the phosphorylation of JNK, p38MAPK, and ERK. CONCLUSIONS: TMP appears to protect against HG-induced VSMC injury through inhibiting reactive oxygen species overproduction, and p38MAPK/JNK/ERK phosphorylation.