Abstract: AIM: To investigate the effects of crocetin on proliferation and collagen synthesis in cultured neonatal rat cardiac fibroblasts (CFB) stimulated by angiotensinⅡ(AngⅡ), and to explore the action mechanism of crocetin. METHODS: We used cultured cardiac fibroblasts from neonatal 1-3 days rat and treating with AngⅡ to induce fibrosis model. The effects of crocetin on proliferation of CFB were observed by MTT assay, synthesis of collagen was observed by the hydroxyproline concentration measured. Cell cyclin distribution was determined with flow cytometre. CollagenⅠ, collagen Ⅲ, matrix metalloproteinase (MMP-2), the tissue inhibitor metalloproteinase (TIMP-1) and TGF-β₁ mRNA expression were examined by Q-PCR. The expression of P27 was tested by Western blotting. RESULTS: Within a concentration coverage, crocetin inhibited CFB proliferation and collagen synthesis induced by AngⅡ in a dose-dependent manner. The percentage of cells in G₀/G₁ phase in crocetin groups increased with concentration, the percentage of cells in S and G₂/M phases and the proliferation index in crocetin groups decreased with concentration, which compared with AngⅡ group difference was statistically significant (P<0.05, P<0.01, respectively). Crocetin decreased the levels of CollagenⅠmRNA, Collagen Ⅲ mRNA, TIMP1 mRNA and TGF-β₁ mRNA expression, but increased MMP-2 mRNA expression. ④Crocetin decreased the protein expression of P27 stimulated by AngⅡ. CONCLUSION: Crocetin inhibited CFB proliferation and collagen synthesis stimulated by AngⅡ, which related to the cytokines excreting and the regulation of extracellular matrix.

Key words: Crocetin, Cardiac fibroblasts, AngiotensinⅡ, Collagen