Aging Reduces the Expression of Lung CINC and MCP-1 mRNA in a P. aeruginosa Rat Model of Infection

We investigated dynamic changes of inflammatory cell infiltration and expression of cytokine-induced neutrophil chemoattractant (CINC) and monocyte chemoattractant protein-1 (MCP-1) mRNA in aged rats with Pseudomonas aeruginosa pulmonary infection. Disease manifestation and lung tissue pathology (lesion dispersion, inflammatory reactions, tissue edema and bleeding) were more severe in aged rats than young rats. At various time points, lung tissue polymorphonuclear neutrophil and mononuclear macrophage numbers were lower in the aged group than the young group ( P < 0.05), and at 24 h there was no difference in mononuclear macrophage numbers. After inoculation with P. aeruginosa , CINC and MCP-1 mRNA expression increased in both groups, but the peak lagged in old rats compared with young. Thus, aging can reduce the expression of CINC and MCP-1 mRNA in lung tissues, and reduce the infiltration of neutrophils and monocyte–macrophages induced by CINC and MCP-1. This might lead to increased risk of pneumonia in elderly patients.