Interleukin-12p40 contributes to protection against lung injury after oral Yersinia enterocolitica infection

The impact of Yersinia enterocolitica on lung is incompletely understood, so we studied the inflammatory effects of Yersinia oral infection and the influence of IL-12p40 deficiency. Wild-type (WT) and IL-12p40-/- (KO) mice were orally infected with Y. enterocolitica 0:3. After 3 and 21 days, cell viability in bronchoalveolar lavage (BAL) fluid, inflammatory reactions, lipid hydroperoxides, antioxidant enzyme expression and histological changes were studied. An effect on the lung was demonstrated by changes in lactate dehydrogenase, total protein (p < 0.001), nitrosative stress and increase numbers of lymphocyte in the BAL fluid. All of these appeared to be IL-12 - independent since statistically significant changes in response to infection (at 21 days) did not differ between WT and KO groups. However, a protective role of IL-12 after infection was suggested by a decrease in cell viability, histopathological changes, different cell populations, higher lipid peroxidation and a decrease in antioxidant enzymes - glutathione peroxidase, superoxide dismutase-2 (p < 0.05). The main changes were detected at day 21 suggesting a chronic effect of Yersinia infection and that IL-12 could play a role in the protection against chronic sequelae in the lung. These results demonstrate that Y. enterocolitica infection may induce inflammatory response in lung and that IL-12p40 could contribute to protection against lung injury.