Emodin Inhibits Lipopolysaccharide-Induced Inflammation by Activating Autophagy in RAW 264.7 Cells

• 作者: TU Yan-jie TAN Bo JIANG Lei WU Zhong-hua YU Hong-ji LI Xiao-qian YANG Ai-dong
• 来源期刊: 中国结合医学杂志（英文版）
• 年，卷（期）: 2021,（5）
• 所属期刊栏目: Original Articles
• 页码范围: 345-352
• 页数: 8页
• 语种: 英文
• DOI: 10.1007/s11655-020-3477-9

摘要

Objective:To investigate the effects of emodin on inflammation and autophagy in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages and reveal its underlying mechanism.Methods:3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay was conducted to find the appropriate dose for emodin.RAW264.7 cells pretreated with different concentrations(0-50 μ mol/L) of emodin or vehicle for 2 h prior to exposure to LPS for 16 h.Cell morphology was examined and propidium iodide staining was used to examine cell cycle.Expressions of inflammation-related proteins[nuclear factor-kappaB (NF-κ B) and Ⅰ-kappaB (Ⅰ κ B) α]and autophagy-related proteins[light chain (LC)3,P62/sequestosome 1,mammalian target of rapamycin (mTOR),and p-mTOR]were examined using Western blot analysis.Expression of inflammation-related cytokines including tumor necrosis factor (TNF)-α,interleukin(IL)-1 β and IL-6 were detected by enzyme-linked immunosorbent assay.Autophagy was examined with LC3B fluorescence intensity and aggregation.The effect of emodin on autophagy was conducted witlh an autophagy inhibitor,3-methyladenine (3-MA).Results:The expression of NF-κ B in LPS-induced cells was significantly increased (P＜0.01) and simultaneously Ⅰκ B α decreased compared with the normal cell (P＜0.05).The expressions of TNF-α,IL-1 β,and IL-6 proteins in the LPS-induced RAW264.7 cells were significantly higher than in the normal cell (P＜0.05 or P＜0.01).LPS increased the percentage of cells in the G0/G1 phase,which was recovered by emodin at different doses (12.5,25,and 50 μ mol/L,P＜0.05 or P＜0.01).The medium-dose (25 μml/L) emodin decreased the expressions of NF-κ B,P62 and p-mTOR (P＜0.01) and increasedⅠ κ B α expression,LC3B Ⅱ/Ⅰ ratio as well as LC3B fluorescence intensity (P＜0.05 or P＜0.01).Meanwhile,the enhanced autophagic effects of emodin,such as the increment of LC3B Ⅱ/ratio and the decrement of P62 expression,were suppressed by autophagy inhibitor 3-MA.Conclusion:Emodin could inhibit inflammation of mice RAW264.7 macrophages induced by LPS,possibly through activating autophagy.