Effect of crocetin on vascular smooth muscle cells migration induced by advanced glycosylation end products

- The current results demonstrate for the first time that crocetin can significantly inhibit AGEs-induced VSMCs migration.
- One possible molecular mechanism mediating the anti-migration effect of crocein is via suppression of RAGE expression.
- The suppression of RAGE can reduce the levels of inflammatory factors (TNF-α and IL-6) and decrease activity of MMP-2/9.
- The findings may provide a pharmacological basis for the clinical application of crocetin in diabetic vascular complications.

Crocetin is a major active constituent of Gardenia jasminoides J. Ellis, and can aid in the prevention of cardiovascular disease. The effect and possible mechanism of crocetin on the migration of vascular smooth muscle cells (VSMCs) induced by advanced glycosylation end products (AGEs) were investigated. VSMCs were pre-incubated with or without crocetin and exposed to AGEs subsequently. The invasion of the cells was investigated using a 24-well Cell Invasion Chamber. The anti-proliferative activity of crocetin was evaluated by MTT assay and VSMCs cell-cycle distribution was examined by flow cytometry. Cytokine TNF-α and IL-6 secreted by VSMCs and the amount of matrix metalloproteinase MMP-2 and MMP-9 in the culture supernatant were detected by ELISA. The expression level of RAGE (AGEs receptor), in cells was analyzed by western blot. The results demonstrated that AGEs increased about two-fold migration of VSMCs compared with control (OD = 0.778 ± 0.191 vs OD = 0.413 ± 0.214, P < 0.01), and the proliferation increased by about 20% (OD = 0.335 ± 0.043 vs OD = 0.281 ± 0.037, P < 0.01). Pre-treatment with crocetin (1.0 μM) or RAGE antibody (10 μg/ml) could inhibit the AGEs triggered migration of VSMCs obviously. Furthermore, both crocetin and RAGE antibody inhibited the increase of RAGE protein in VSMCs stimulated by AGEs. The levels of TNF-α and IL-6 decreased in the crocetin (1.0 μM) pre-treated group compared to the AGEs (without pre-treated) group (37.60 ± 3.08 pg/ml vs 46.59 ± 1.92 pg/ml, 32.11 ± 4.69 pg/ml vs 49.99 ± 8.84 pg/ml, respectively). Crocetin (1.0 μM) also reduced the value of MMP-2 and MMP-9 compared with the AGEs group (2.81 ± 0.35 ng/ml vs 6.40 ± 0.85 ng/ml, 2.69 ± 0.25 ng/ml vs 4.32 ± 0.57 ng/ml, respectively). In summary, crocetin inhibits the migration of VSMCs induced by AGEs through RAGE-dependent signaling pathway. And it is meaningful to diabetic vascular complications.