Objective: Modeling the immune-related adverse events (irAE) colitis in mice, and explore the protective effect and related mechanism of Lactobacillus rhamnosus GG (LGG) on irAE colitis. Methods: C57BL/6 mice were divided into dextran sodium sulfate (DSS) group (n=3), DSS+anti-programmed death receptor 1 (PD-1) group (n=4), DSS+anti-PD-1+anti-cytotoxic T lymphocyte associated protein 4 (CTLA-4) Group (n=4), DSS+anti-PD-1+anti-CTLA-4+LGG group (n=4), all were given corresponding drugs and probiotics intervention. The severity of colitis were assessed by weight loss, disease activity index (DAI), colon length, colon histopathological score. The inflammatory cytokines and T cell immunity of CD4+, CD8+, FoxP3+regulatory T cells (Treg), were detected by real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and immunohistochemical staining respectively. Results: Compared to DSS group, the Day 9 weight [(87.40±1.79)% vs (94.57±0.53)%, P<0.05], colon length [(5.33±0.27)cm vs (6.63±0.12)cm, P<0.05] were lower, and DAI score(2.66±0.24 vs 0.89±0.48), colon histopathological score (12.50±1.04 vs 5.67±0.33), tumor necrosis factor-α (TNF-α) (6.73±1.68 vs 0.91±0.40) (P<0.05), as well CD8+T cells (156.80±8.84 vs 89.00±6.66) and FoxP3+Treg cells (103.80±2.66 vs 48.33±3.18) (P<0.05) were higher in DSS+anti-PD-1+anti-CTLA-4 group. Compared to DSS+anti-PD-1+anti-CTLA-4 group, the DAI score(1.83±0.17 vs 2.66±0.24), colonic histopathology score (8.75±0.63 vs 12.50±1.04), TNF-α level (1.32±0.18 vs 6.73±1.68) (P<0.05) were lower; and CD8+T cells(97.75±3.75 vs 156.80±8.84, P<0.01) level was lower with higher FoxP3+Treg cells (126.00±8.33 vs 103.80±2.66, P=0.046) in DSS+anti-PD-1+anti-CTLA-4+LGG group. Conclusion: DSS combined with anti-PD-1 and anti-CTLA-4 can successfully modeling the irAE colitis in mice, LGG can reduce irAE colitis severity by regulating Treg cells.
目的： 建立小鼠免疫治疗相关（irAE）结肠炎模型，探讨鼠李糖乳杆菌（LGG）对irAE结肠炎的保护作用和相关机制。 方法： C57BL/6小鼠分为葡聚糖硫酸钠（DSS）组3只、DSS+抗程序性死亡受体1（PD-1）组4只，DSS+抗PD-1+抗细胞毒性T淋巴细胞相关蛋白4（CTLA-4）组4只、DSS+抗PD-1+抗CTLA-4+LGG组4只，分别给予相应药物和菌群干预。通过体重下降、疾病活动指数（DAI）、结肠长度、结肠组织病理评分，实时荧光定量-聚合酶链式反应（qRT-PCR）检测结肠组织炎性细胞因子，免疫组化染色CD4+、CD8+和FoxP3+调节T细胞。 结果： 与DSS组比较，DSS+抗PD-1+抗CTLA-4组小鼠第9天体重[(87.40±1.79)%比（94.57±0.53)%]和结肠长度[(5.33±0.27)cm比（6.63±0.12)cm]较低（P<0.05)，DAI评分（2.66±0.24比0.89±0.48)、结肠组织病理评分（12.50±1.04比5.67±0.33)、肿瘤坏死因子α（TNF-α）(6.73±1.68比0.91±0.40）较高（P<0.05)；CD8+T细胞（156.80±8.84比89.00±6.66）和FoxP3+调节性T细胞（Treg）(103.80±2.66比48.33±3.18）较多（P<0.05）。与DSS+抗PD-1+抗CTLA-4组比较，DSS+抗PD-1+抗CTLA-4+LGG组小鼠DAI评分（1.83±0.17比2.66±0.24)、结肠组织病理评分（8.75±0.63比12.50±1.04)、炎性因子TNF-α(1.32±0.18比6.73±1.68）均较低（P<0.05）；CD8+T细胞较少（97.75±3.75比156.80±8.84, P<0.01)，FoxP3+Treg细胞较多（126.00±8.33比103.80±2.66, P=0.046)。 结论： DSS联合抗PD-1和抗CTLA-4成功构建小鼠irAE结肠炎模型，补充LGG通过调节Treg细胞减轻irAE结肠炎。.
Keywords: Colitis; Immune-related adverse events; Lactobacillus rhamnosus; T cell immunity.