辣椒素抑制成纤维细胞增殖的作用及其分子机制

Inhibitory effect of capsaicin on fibroblast proliferation and its molecular mechanism

背景:研究报道辣椒素具有抑制纤维化作用,可抑制增生性成纤维细胞增殖能力和胶原合成能力,但是辣椒素抑制成纤维细胞增殖的确切机制尚未明确。目的:探讨辣椒素对抑制表皮成纤维细胞增殖的影响及其相应的分子作用机制。方法:体外原代培养获得新生SD大鼠表皮成纤维细胞,采用不同质量浓度辣椒素(0.5,1,2,4,8 mg/L)作用24 h后,并以不加辣椒素为阴性对照组。倒置显微镜观察表皮成纤维细胞形态变化和MTT法检测皮肤成纤维细胞的存活率及其IC_(50)值,用Hoechst 33258染色法和AnnexinV-FITC/PI双染法观察和检测其细胞凋亡;采用流式细胞术检测表皮成纤维细胞的细胞周期;Western blot检测不同质量浓度的辣椒素(0,2,4,8,16 mg/L)诱导大鼠表皮成纤维细胞FoxO1、p-FoxO1、Akt、p-Akt蛋白表达改变。结果与结论:(1)随着辣椒素质量浓度的增高,表皮成纤维细胞的细胞存活率逐渐降低,且呈现浓度依赖性,其IC_(50)值为3.55 mg/L;(2)与对照组相比,辣椒素作用于表皮成纤维细胞24 h后,表皮成纤维细胞阻滞在G_1期而且凋亡率增加,同时能降低p-Akt及p-FoxO1的蛋白表达水平;(3)结果说明,辣椒素能抑制皮肤成纤维细胞的增殖、促进细胞凋亡,且呈现浓度依赖效应,Akt-FoxO1信号通路可能参与了辣椒素的抑制增殖效应。

BACKGROUND: Capsaicin has been reported to inhibit fibrosis and the proliferation and collagen synthesis of hypertrophic fibroblasts. However, the underlying mechanism is unclear. OBJECTIVE: To investigate the effect of capsaicin on inhibiting the proliferation of fibroblasts and the corresponding molecular mechanism. METHODS: Neonatal Sprague-Dawley rat epidermal fibroblasts were cultured in vitro, and were treated with capsaicin at different concentrations (0.5, 1, 2, 4, 8 mg/L) for 24 hours. The cells without treatment of capsaicin were included in the negative control group. Morphological changes of the epidermal fibroblasts were observed under phase-contrast microscope. The cell viability and IC50 value were detected by MTT assay. The cell apoptosis was detected by Hoechst 33258 staining and AnnexinV-FITC/PI staining. The cell cycle distribution was determined by flow cytometry. The protein expression levels of FoxO1, p-FoxO1, Akt and p-Akt were detected by western blot assay. RESULTS AND CONCLUSION: With capsaicin concentration increasing, cell survival rate decreased gradually in a concentration-dependent manner, and IC50 value was 3.55 mg/L. Compared with the negative control group, after 24 hours, capsaicin treated fibroblasts stopped in G1 phase and the apoptosis rate increased. Meanwhile, capsaicin could decrease the expression of P-Akt and P-FoxO1. Therefore, capsaicin can inhibit the proliferation of fibroblasts, promote cell apoptosis, and present a concentration-dependent effect. The Akt-FoxO1 signaling pathway may be involved in the inhibition of capsaicin on fibroblast proliferation.