Table_2_Alleviation of DSS-induced colitis in mice by a new-isolated Lactobacillus acidophilus C4.XLS

IntroductionProbiotic is adjuvant therapy for traditional drug treatment of ulcerative colitis (UC). In the present study, Lactobacillus acidophilus C4 with high acid and bile salt resistance has been isolated and screened, and the beneficial effect of L. acidophilus C4 on Dextran Sulfate Sodium (DSS)-induced colitis in mice has been evaluated. Our data showed that oral administration of L. acidophilus C4 remarkably alleviated colitis symptoms in mice and minimized colon tissue damage.
MethodsTo elucidate the underlying mechanism, we have investigated the levels of inflammatory cytokines and intestinal tight junction (TJ) related proteins (occludin and ZO-1) in colon tissue, as well as the intestinal microbiota and short-chain fatty acids (SCFAs) in feces.
ResultsCompared to the DSS group, the inflammatory cytokines IL-1β, IL-6, and TNF-α in L. acidophilus C4 group were reduced, while the antioxidant enzymes superoxide dismutase (SOD), glutathione (GSH), and catalase (CAT) were found to be elevated. In addition, proteins linked to TJ were elevated after L. acidophilus C4 intervention. Further study revealed that L. acidophilus C4 reversed the decrease in intestinal microbiota diversity caused by colitis and promoted the levels of SCFAs.
DiscussionThis study demonstrate that L. acidophilus C4 effectively alleviated DSS-induced colitis in mice by repairing the mucosal barrier and maintaining the intestinal microecological balance. L. acidophilus C4 could be of great potential for colitis therapy.

引言
益生菌（Probiotic）是溃疡性结肠炎（UC）传统药物治疗的辅助疗法。本研究分离筛选出一株耐酸耐胆盐的嗜酸乳杆菌（Lactobacillus acidophilus）C4，并评估了该菌株对硫酸葡聚糖钠（Dextran Sulfate Sodium, DSS）诱导的小鼠结肠炎的益生功效。研究数据显示，口服嗜酸乳杆菌C4可显著缓解小鼠结肠炎症状，并减轻结肠组织损伤。
方法
为阐明其潜在作用机制，本研究检测了结肠组织中炎症细胞因子及肠上皮紧密连接（tight junction, TJ）相关蛋白（闭合蛋白（occludin）和闭锁小带蛋白1（ZO-1））的表达水平，同时分析了粪便样本中的肠道菌群与短链脂肪酸（short-chain fatty acids, SCFAs）含量。
结果
与DSS模型组相比，嗜酸乳杆菌C4干预组小鼠体内的炎症细胞因子IL-1β、IL-6及TNF-α水平显著降低；而抗氧化酶超氧化物歧化酶（superoxide dismutase, SOD）、谷胱甘肽（glutathione, GSH）及过氧化氢酶（catalase, CAT）的活性或含量显著升高。此外，嗜酸乳杆菌C4干预可上调紧密连接相关蛋白的表达。进一步研究发现，该菌株可逆转结肠炎导致的肠道菌群多样性降低，并提升粪便中短链脂肪酸的水平。
讨论
本研究证实，嗜酸乳杆菌C4可通过修复黏膜屏障、维持肠道微生态平衡，有效缓解DSS诱导的小鼠结肠炎。嗜酸乳杆菌C4在结肠炎治疗领域具有良好的应用潜力。