Changes of IFN-γ, IL-6 and TNF-α levels in rats with severe pneumonia

AIM:To study the variety of cytokines in severe bacterial pneumonia of Sprague Dawleg (SD) rats. METHODS:A total of 60 SD rats were randomly divided into three groups: model Ⅰ group (n=24), model Ⅱ group (n=24), and control group (n=12). Rats in the model Ⅰ group and the model Ⅱ group were intratracheally instilled with suspension of klebsiella pneumoniae at different doses. Rats in the control group were intratracheally injected with 1 mL saline. On the 2nd, 4th and 6th day after intratracheal instillation, 1/3 rats in each group were killed to determine the concentration of IFN-γ, IL-6 and TNF-α in blood. RESULTS:The levels of IL-6 and TNF-α in model groups were higher than those in control group, while the level of IFN-γ was lower. The change of cytokines was more significant in the model Ⅱ group (severe pneumonia) than those in the model Ⅰ group. CONCLUSION:The cytokines we studied may play an important role in the pathogenesis of severe pneumonia. The change of cytokines is more significant in severe pneumonia than those in common pneumonia.