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目的:研究多形螺旋线虫(H.polygyrus)感染对CD4~+辅助性T细胞介导的小鼠炎症性肠病(IBD)的影响及其作用机制。方法:用卵清蛋白(OVA)特异性的CD4~+辅助性T细胞转入重度联合免疫缺陷(SCID)小鼠中制作IBD模型。将IBD小鼠感染H.polygyrus,14d后处死小鼠,观察结肠的组织学变化,用ELISA法和流式细胞术检测肠系膜淋巴结中干扰素-γ(IFN-γ)和白细胞介素-4(IL-4)的表达。另外,对感染H.polygyrus的IBD小鼠注射IL-4单克隆抗体以阻断IL-4的分泌,9d后处死小鼠,观察相同的指标。结果:与无感染组相比,感染H.polygyrus的IBD小鼠结肠病损明显加重,肠系膜淋巴结中IL-4水平明显增高,IFN-γ水平明显降低(均P<0.05)。在IL-4阻断实验中,与无IL-4阻断组相比,IL-4阻断组结肠病损明显减轻,IL-4水平明显降低,IFN-γ水平明显增高(均P<0.05)。结论:H.polygyrus感染在CD4~+ T细胞介导的IBD模型早期加重了炎症反应,其作用可能是通过诱导Th2细胞因子的分泌、抑制Th1细胞因子的分泌来实现的,提示用蠕虫治疗IBD时需谨慎。
Objective: To investigate the effect and mechanism of H.polygyrus infection on inflammatory bowel disease (IBD) mediated by CD4 ~ + helper T cell in mice. Methods: OVA-specific CD4 ~ + helper T cells were transfected into severe combined immunodeficiency (SCID) mice to produce IBD model. The IBD mice were infected with H.polygyrus, and the mice were killed after 14 days. The histological changes of the colon were observed. The levels of IFN-γ and IL-4 were measured by ELISA and flow cytometry IL-4) expression. In addition, IBD mice infected with H. polygyrus were injected with IL-4 monoclonal antibody to block the secretion of IL-4, and mice were sacrificed 9 days later to observe the same index. Results: IBD mice infected with H.polygyrus had significantly more colonic lesions and IL-4 levels in mesenteric lymph nodes and IFN-γlevel significantly lower than those in non-infected group (all P <0.05). In the IL-4 blocking assay, the IL-4 blocking group showed a significant reduction in colonic lesions, a significant decrease in IL-4 levels and a significant increase in IFN-γ levels compared with the IL-4 blocking group (all P <0.05 ). Conclusions: H.polygyrus infection exacerbates the inflammatory response early in the IBD model mediated by CD4 ~ + T cells. The effect may be through inducing the secretion of Th2 cytokines and inhibiting the secretion of Th1 cytokines, suggesting that the worm treatment of IBD Be cautious.