Abstract：To study the pathological changes and expressions of interleukin 17 (IL-17), tumor necrosis factor α (TNF-α) and Toll-like receptor 4 (TLR4) in local tissues with administration of Pseudomonas aeruginosa mannose sensitive hemagglutinin (PA-MSHA), 30 mice were randomly divided into two groups, and received subcutaneous injection of PA-MSHA and normal saline respectively. The local injection tissues were sectioned at 6, 12, 24, 48 and 72 h after injection, and the pathological changes and expressions of IL-17, TNF-α and TLR4 were detected by hematoxylin-eosin (HE) and immunohistochemical staining, and measured by image analysis. The results revealed that PA-MSHA caused acute inflammation with predominant neutrophil infiltration in the local injection tissues. In the inflammation lesions, the expression levels of IL-17, TNF-α and TLR4 were elevated at 6 h after injection, peaked at 24 h, then decreased gradually, and were comparable to the control group at 72 h. The expression levels of these three cytokines were consistent with the degree of inflammation. The data suggest that subcutaneous injection of PA-MSHA induces acute inflammation and changes the immunity state of local injection tissues.
