发酵乳杆菌LFQ153胞外多糖对RAW264.7巨噬细胞氧化损伤的保护作用

Protective effect of exopolysaccharide from Lactobacillus fermentum LFQ153 against oxidative damage in RAW264.7 macrophages

为探究发酵乳杆菌LFQ153胞外多糖(exopolysaccharides,EPS)对RAW264.7巨噬细胞氧化损伤的保护作用与机制,该研究以DPPH自由基和羟自由基清除能力研究EPS的体外抗氧化水平。通过脂多糖(lipopolysaccharide,LPS)刺激RAW264.7巨噬细胞建立氧化损伤模型,以抗氧化酶活力、丙二醛(malondialdehyde,MDA)和NO含量,及炎症因子表达为指标,研究EPS对细胞氧化损伤的保护作用。以Nrf2/HO-1/NF-κB通路相关基因表达水平,探讨EPS保护细胞氧化损伤的作用机制。此外,该研究采用离子色谱分析EPS的单糖组成。结果表明,EPS的DPPH自由基和羟自由基清除率分别为(64.19±1.03)%和(61.87±3.09)%。与LPS处理组相比,EPS可显著提高巨噬细胞超氧化物歧化酶、过氧化氢酶和谷胱甘肽过氧化物酶的活力,降低MDA和NO含量,以及诱导型一氧化氮激酶、肿瘤坏死因子-α、白介素1β和白介素6的mRNA表达水平。并且,EPS促进氧化损伤巨噬细胞中Nrf2和HO-1的mRNA表达,抑制NF-κB的活化。此外,结构分析表明EPS由盐酸氨基葡萄糖、半乳糖、葡萄糖和甘露糖组成,摩尔比为2.48∶10.26∶50.22∶8.16。该研究表明,EPS可以保护巨噬细胞氧化损伤,且这种保护作用与Nrf2/HO-1/NF-κB通路的调节及EPS的单糖组成有关。

In order to investigate the protective effects and underlying the mechanisms of exopolysaccharides(EPS)from Lactobacillus fermentum LFQ153 against oxidative damage in RAW264.7 macrophages,the current study evaluated the in vitro antioxidant activity of EPS using the DPPH and·OH radical scavenging ability,and established the cell model of oxidative damage by stimulating RAW264.7 macrophages with lipopolysaccharide(LPS).The protective effects of EPS against cell oxidative damage were investigated based on the activity of antioxidant enzymes,the content of malondialdehyde(MDA)and NO,and the expression of inflammatory cytokines.The expression of nuclear factor E2-related factor 2/heme oxygenase-1/nuclear factor-κB(Nrf2/HO-1/NF-κB)pathway-related genes was analyzed to explore the protective mechanisms of EPS against cell oxidative damage.In addition,the monosaccharide composition of EPS was assayed by ion chromatography in the present study.The DPPH and·OH radical scavenging rates of EPS were(64.19±1.03)%and(61.87±3.09)%,respectively.Compared with LPS treatment group,EPS supplement significantly increased the activities of superoxide dismutase,catalase and glutathione peroxidase in macrophages,and decreased the contents of MDA and NO,as well as the mRNA expression levels of nitric oxide synthase,tumor necrosis factor-α,interleukin(IL)-1βand IL-6.Moreover,EPS promoted the mRNA expression levels of Nrf2 and HO-1,and inhibited the activation of NF-κB in macrophages with oxidative damage.In addition,the structural analysis showed that EPS was composed of glucosamine hydrochloride,galactose,glucose and mannose with the molar ratio of 2.48∶10.26∶50.22∶8.16.Our study indicates that EPS may protect macrophages against oxidative damage,and this protective effect is associated with the regulation of Nrf2/HO-1/NF-κB pathway and the monosaccharide composition of EPS.