Effects of apigenin on lipopolysaccharide induced proliferation of rat aortic vascular smooth muscle cells

Abstract

Objective: To investigate the effect of natural active compounds apigenin (API) on the proliferation of rat aortic vascular smooth muscle cells (VSMCs) induced by lipopolysaccharide (LPS) and related mechanisms. Methods: VSMCs of primary cultured SD rats were obtained and the cytotoxic effects of API (0, 10, 20, 40 and 80 μmol/L) was explored by CCK-8 method. Impact of LPS (0, 0.1, 1, 10 and 100 μg/ml) on VSMCs proliferation and the impact of API (0, 10, 20, 40 μmol/L) on LPS (10 μmol)-induced VSMCs proliferation by CCK-8 methods. Using EdU and FCM method, we observed the effect of API on proliferation of VSMCs induced by LPS. VSMCs proliferation and cell cycle were also assessed by EdU method and FACS in 10 μg/ml LPS, 10 μg/ml LPS+ 40 μmol/L API and equal volume DMSO treated VSMCs. Results: (1) CCK-8 cell vitality test showed that cell vitality was not affected by 0-40 μmol/L API, while cell vitality was significantly reduced by 80 μmol/L API (57%), which was significantly lower than in blank group (P<0.05). (2) VSMCs proliferation was significantly promoted by 0.1, 1 and 10 μg/ml LPS and peaked in 10 μg/ml LPS stimulated VSMCs group, while VSMCs proliferation was significantly reduced in 100 μg/ml LPS stimulated group (P<0.05 vs. blank group). (3) LPS (10 μm/ml) induced VSMCs proliferation was not affected by 10 μmol/L API, which was significantly inhibited by 20 and 40 μmol/L API (both P<0.05 vs. LPS). (4) VSMCs proliferation assessed by EdU was significantly higher in LPS group than in blank group (P<0.01), which could be significantly reduced by cotreatment with API (P<0.01). (5) FACS results showed that percent of VSMCs in G0/G1 stage was significantly lower in LPS group compared to blank group (P<0.05), which could be significantly increased post API treatment (P<0.05 vs. LPS), while percent of VSMCs in S stage was significantly lower post API treatment in comparison with LPS group. Conclusion: API can significantly inhibit LPS-induced proliferation of VSMCs, partly through inhibiting mitosis and inducing G0/G1 cell cycle arrest.