[摘 要] 目的：探究2'-岩藻糖基乳糖（2'-FL）对小鼠免疫检查点抑制剂（ICI）相关结肠炎（ICIC）的作用及其机制。方法：用随 机数字表法将BALB/c小鼠随机分为对照组、葡聚糖硫酸钠（DSS）组、ICIC组、ICIC + 2'-FL组。DSS组连续7 d自由摄取含3.5% DSS的饮用水诱导结肠炎；ICIC组在摄取含3.5% DSS的饮用水的同时在实验第0天和第4天通过腹腔注射细胞毒性T淋巴细胞 相关抗原4抗体（CTLA?4抗体，剂量为150 μg/只）构建ICIC模型；ICIC + 2'-FL组在ICIC造模同时从实验开始每日灌胃给予2'-FL [150 mg/(kg·d）]。统计分析小鼠体质量和疾病活动性评分（DAI）变化。第7天处死小鼠，测量结肠长度，用H-E染色法观察各组 结肠组织学形态变化，用免疫组织化学（IHC）法检测CD3+ T细胞和CD19+ B细胞在结肠组织中的浸润情况，用转录组学方法对结 肠组织进行RNA测序，统计分析各组结肠组织中的差异表达基因（DEG）并进行基因本体论（GO）功能注释和京都基因与基因组 百科全书（KEGG）富集分析。结果：与对照组和 DSS 组比较，ICIC 组小鼠体质量明显下降、DAI评分上升、结肠长度更短（均 P < 0.05），结肠黏膜完整性受损，呈现典型的溃疡性病变；与ICIC组比较，ICIC + 2'-FL组小鼠体质量下降显著缓解、DAI评分降 低，结肠长度恢复（均P < 0.05)。转录组学检测结果显示，与ICIC组相比，2'-FL处理组有51个DEG，GO功能注释和KEGG富集 分析提示，2'-FL缓解ICIC样症状与B细胞受体、B细胞增殖调控、炎症反应和修复相关通路的上调有关。结论：人乳寡糖2'-FL 可显著缓解ICIC的病理进程，其可能通过B细胞受体相关信号通路及与炎症反应和修复相关通路减轻ICIC小鼠结肠组织的损伤。

[Abstract] Objective: To investigate the effect of 2'-fucosyllactose (2'-FL) on immune checkpoint inhibitor-induced colitis (ICIC) in mice and its possible mechanisms. Methods: BALB/c mice were randomly assigned into the normal control (NC) group, dextran sulfate sodium (DSS) group, ICIC group, and ICIC + 2'-FL group, using a random number table method. Mice in the DSS group were provided with 3.5% DSS-containing drinking water for seven days to induce colonic inflammation. The ICIC group was intraperitoneally injected of cytotoxic T lymphocyte-associated antigen 4 (CTLA-4; dose: 150 μg) on day 0 and day 4, while simultaneously consuming 3.5% DSS-containing drinking water. The ICIC + 2'-FL group received daily intragastric administration of 2'-FL (150 mg/[kg·d]) concurrently with the establishment of ICIC model. Changes in body weight and disease activity index (DAI) were statistically analyzed. On day 7, all mice were sacrificed, and the colon length was measured. Hematoxylin and eosin (H&E) staining was performed to observe histomorphological changes in colon tissues across groups. Immunohistochemistry (IHC) was conducted to assess the infiltration of CD3+ T cells and CD19+ B cells in colonic tissues. RNA sequencing (RNA-seq) was performed on colon tissues. The differentially expressed genes (DEGs) were subjected to Gene Ontology (GO) functional annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. Results: Compared with the NC and DSS groups, the ICIC group showed significant body weight loss, elevated DAI scores, and shorter colon length (all P <0.05); besides, the colon mucosal integrity was damaged, with typical ulcerative lesions. Compared with the ICIC group, ICIC + 2'-FL group demonstrated significantly alleviated body weight loss, reduced DAI score, and restored colon length (all P < 0.05). Transcriptomic results revealed 51 DEGs in the ICIC + 2'-FL group (vs ICIC group). GO functional annotation and KEGG enrichment analysis suggested that the protective effect of 2'-FL against ICIC-like symptoms might be associated with upregulation of signaling pathways related to B cell receptor, B cell proliferation regulation, inflammatory responses, and tissue repair. Conclusion: Human milk oligosaccharide 2'-FL significantly alleviates the pathological progression of ICIC by modulating B-cell receptor-related signaling pathways and pathways associated with inflammation responses and tissue repair, thereby reducing colonic damage in ICIC mice.

[基金项目] 中国博士后科研基金（No. 2021M700546）；江苏省卫健委科研课题（No. MQ2024030）；常州市科技计划项目（No. CJ20245049； No. CE20235066）；南京医科大学常州医学中心重点项目（No. CMCM202314）；南通大学临床专项（No. 2023LY027）