Grimm M C, Elsbury S K, Pavli P, Doe W F
Division of Molecular Medicine, John Curtin School of Medical Research, Australian National University, Canberra, Australia.
Gut. 1996 Jan;38(1):90-8. doi: 10.1136/gut.38.1.90.
Neutrophils are important cellular mediators in inflammatory bowel disease (IBD). Interleukin (IL)8, a powerful neutrophil chemoattractant, is found in increased quantities in inflamed mucosa, but the cells of origin are uncertain. IL8 gene expression was studied by in situ hybridisation in uninflamed intestinal tissue resected for colon carcinoma (n = 7) and in inflamed colonic tissue resected for IBD (n = 11). Immunohistochemistry was used to assess the phenotype of IL8 expressing macrophages and the production of IL8 protein. Macrophages isolated from intestinal resections and lipopolysaccharide stimulated peripheral blood monocytes treated with 5-aminosalicylic acid, hydrocortisone, and cyclosporin A were examined for IL8 mRNA by northern blotting and IL8 secretion by enzyme linked immunosorbent assay (ELISA). In all cases IL8 mRNA was detected by in situ hybridisation in macrophages and neutrophils adjacent to ulceration in inflamed bowel, but not detected in uninflamed mucosa from carcinoma resections. Recently recruited CD14 positive macrophages were responsible for some of this IL8 expression. IL8 protein was present in the same distribution as mRNA. Epithelial cells in normal and inflamed tissue showed neither mRNA nor protein. IL8 mRNA was expressed significantly more commonly by macrophages from IBD affected than from normal mucosa, and IL8 secretion by IBD but not normal colon macrophages was augmented significantly by lipopolysaccharide treatment. IL8 expression and production by lipopolysaccharide treated blood monocytes was inhibited by the therapeutic agents tested. These results show that neutrophils and recently recruited macrophages are responsible for production of IL8 in IBD, suggesting a mechanism for a continuing cycle of neutrophil attraction. Agents used therapeutically in these diseases may be effective in part by disrupting this cycle.
中性粒细胞是炎症性肠病（IBD）中重要的细胞介质。白细胞介素（IL）-8是一种强大的中性粒细胞趋化因子，在炎症黏膜中含量增加，但其来源细胞尚不确定。通过原位杂交研究了因结肠癌切除的未发炎肠组织（n = 7）和因IBD切除的发炎结肠组织（n = 11）中IL-8基因的表达。采用免疫组织化学方法评估表达IL-8的巨噬细胞的表型和IL-8蛋白的产生。通过Northern印迹法检测从肠道切除组织中分离的巨噬细胞以及用5-氨基水杨酸、氢化可的松和环孢素A处理的脂多糖刺激的外周血单核细胞中的IL-8 mRNA，并通过酶联免疫吸附测定（ELISA）检测IL-8分泌。在所有病例中，通过原位杂交在发炎肠溃疡附近的巨噬细胞和中性粒细胞中检测到IL-8 mRNA，但在癌切除的未发炎黏膜中未检测到。最近招募的CD14阳性巨噬细胞是这种IL-8表达的部分原因。IL-8蛋白的分布与mRNA相同。正常和发炎组织中的上皮细胞既未显示mRNA也未显示蛋白。与正常黏膜相比，IBD患者受影响的巨噬细胞中IL-8 mRNA的表达明显更常见，脂多糖处理显著增加了IBD患者而非正常结肠巨噬细胞的IL-8分泌。所测试的治疗药物抑制了脂多糖处理的血液单核细胞中IL-8的表达和产生。这些结果表明，中性粒细胞和最近招募的巨噬细胞是IBD中IL-8产生的原因，提示了中性粒细胞吸引持续循环的机制。这些疾病中使用的治疗药物可能部分通过破坏这个循环而有效。
