骨髓细胞来源的CD1d基因敲除拮抗DSS诱导的结肠炎

Myeloid derived CD1d knockout mice antagonize DSS-induced colitis

目的使用骨髓嵌合小鼠探究骨髓来源细胞的CD1d基因敲除在小鼠结肠炎进程中的调节作用及其可能的作用机制。方法取SPF级C57BL/6、CD1d^(-/-)小鼠全身一次性接受10 Gy剂量^(60)Co的放射源进行γ射线照射3 h后接受骨髓移植构建4组骨髓嵌合小鼠,饮用2.5%DSS连续7 d,每天记录各组小鼠的体质量变化、活动情况、粪便性状等并且评估小鼠的疾病活动指数(DAI)。第7天用FITC-dextran灌胃检测各组小鼠肠通透性、测量其结肠长度,并用H&E染色法观察结肠组织的病理学变化。免疫印迹检测各组小鼠肠组织炎性因子的表达。结果骨髓嵌合小鼠模型研究显示,与移植入WT骨髓细胞的小鼠相比,移植入CD1d^(-/-)骨髓细胞的小鼠质量下降缓慢、疾病活动指数(DAI)低(P<0.05),结肠长度长(P<0.01),肠通透性低(P<0.01),肠黏膜损伤轻、浸润的炎性细胞少。肠组织NLRP3蛋白及其底物IL-18表达高(P<0.05)。结论骨髓细胞来源的CD1d基因敲除能够拮抗DSS诱导的结肠炎,且可能是通过促进NLRP3炎性小体及其底物IL-18的表达发挥作用。

This study was performed to determine whether bone marrow-derived CD1d knockout plays a role in DSS-induced enteritis model. SPF C57BL/6 and CD1d^-/- mice underwent whole body 60 Co gamma-ray irradiation with a dose of 10 Gy to ablate their bone marrow for 3 h, and then 4 groups of bone marrow chimeric mice were constructed by bone marrow transplantation after. Colitis model was constructed by daily 2.5% DSS feeding for 7 days. The changes in body weight, activity conditions, fecal traits were recorded every day and DAI of mice was assessed. On the 7th day, intestinal permeability was measured by FITC-dextran gavage and the length of the colon was measured; the histopathological changes of the colon were observed by HE staining. Furthermore, Western blot was used to detect the expression of inflammatory cytokines in the colon tissue of mice. Data showed that compared with WT bone marrow mice, CD1d^-/- bone marrow mice lost more weight and had lower DAI, and demonstrated longer colon length (P<0.05), lower intestinal permeability (P<0.01), lighter intestinal mucosal damage, less inflammatory cells infiltration, and higher expression levels of NLRP3 and IL-18 (P<0.05). These combined data suggest that myeloid derived CD1d knockout mice can antagonize DSS-induced colitis, and the mechanism may relate to promoting the expression of NLRP3 inflammasome and its substrates IL-18.