植物乳植杆菌IMAU30043胞外多糖对脂多糖诱导的RAW264.7巨噬细胞氧化损伤的保护作用

Protection of Exopolysaccharide from Lactiplantibacillus plantarum IMAU30043 Against Oxidative Damage in RAW264. 7 Macrophages

摘要:

为探究植物乳植杆菌IMAU30043胞外多糖（exopolysaccharides，EPS）对RAW264.7巨噬细胞氧化损伤的保护作用，作者以还原能力、超氧阴离子自由基抑制能力和DPPH自由基清除能力来评价EPS的体外抗氧化水平。通过离子色谱分析IMAU30043 EPS的组成，并采用脂多糖（lipopolysaccharide，LPS）刺激RAW264.7巨噬细胞建立氧化损伤模型，测定其超氧化物歧化酶（superoxide dismutase，SOD）酶活力、丙二醛（malondialdehyde，MDA）质量摩尔浓度、NO质量摩尔浓度及炎症因子表达水平的变化。根据Nrf2/HO-1/NF-κB通路关键基因表达水平的变化，探讨EPS保护细胞免受氧化损伤和抑制炎症反应的作用机制。结果表明，IMAU30043 EPS的体外抗氧化活性最强，由岩藻糖、鼠李糖、半乳糖、葡萄糖、木糖、甘露糖、葡萄糖醛酸和甘露糖醛酸组成，其摩尔比为4.50∶51.49∶256.73∶95.96∶3.64∶5.35∶111.10∶16.93。另外，EPS可显著提高LPS诱导的RAW264.7巨噬细胞氧化损伤后的SOD酶活力，降低MDA和NO质量摩尔浓度；在基因水平上能显著下调iNOS、TNF-α、IL-1β和IL-6的表达量，但显著上调IL-10的表达量。此外，EPS促进了模型细胞中Nrf2和HO-1基因的mRNA表达，并抑制了NF-κB的激活。表明植物乳植杆菌IMAU30043产生的EPS能有效保护巨噬细胞免受氧化损伤，且该功能与Nrf2/HO-1/NF-κB信号通路有关。

Abstract:

To explore the protective effect of exopolysaccharides (EPS) of Lactiplantibacillus plantarum IMAU30043 on oxidative damage in RAW264.7 macrophages, the author assessed the in vitro antioxidant activity of EPS using reducing ability, superoxide anion free radical inhibition ability, and DPPH free radical scavenging ability. The composition of IMAU30043 EPS was analyzed by ion chromatography, and an oxidative damage model in RAW264.7 macrophages was established by stimulating the cells with lipopolysaccharide (LPS). The changes in superoxide dismutase (SOD) enzyme activity, malondialdehyde (MDA) and NO molality, and inflammatory factor expression levels were determined. In addition, the mechanism by which EPS protect cells from oxidative damage and inhibit inflammatory responses were further investigated by analyzing the expression levels of key genes in the Nrf2/HO-1/NF-κB signaling pathway. The results showed that IMAU30043 EPS exhibited strong in vitro antioxidant activity and were composed of fucose, rhamnose, galactose, glucose, xylose, mannose, glucuronic acid, and mannuronic acid, with a molar ratio of 4.50∶51.49∶256.73∶95.96∶3.64∶5.35∶111.10∶16.93. Additionally, EPS significantly increased SOD enzyme activity and reduced the MDA and NO molality following LPS-induced oxidative damage in RAW264.7 macrophages. At the gene level, EPS significantly down-regulated the expression of iNOS, TNF-α, IL-1β, and IL-6, while up-regulating IL-10 expression. Moreover, EPS enhanced the mRNA expression of Nrf2 and HO-1 gene and inhibited NF-κB activation in the model cells. This study found that the EPS from Lactiplantibacillus plantarum IMAU30043 can effectively protect macrophages from oxidative damage, with this protective effect being associated with the Nrf2/HO-1/NF-κB signaling pathway.