Inflammation is attenuated in S100A9 knockout mice undergoing a 2-hit lung injury model.

<p>Cytokine and chemokine concentrations in lung lavage fluid of wild-type (WT) and S100A9 knockout (KO) mice. Animals were spontaneously breathing (C), high tidal mechanically ventilated (HV_T MV), exposed to LPS followed by spontaneously breathing (LPS), or exposed to LPS followed by HV_T mechanical ventilation (HV_T MV+LPS). Levels of interleukin (IL)–6 (A), macrophage inflammatory protein (MIP)-2 (B), tumor necrosis factor-α (TNF-α) (C), IL-1β (D), and keratinocyte–derived chemokine (KC) (E) were determined. Data represent means (SEM) of 6–8 mice per group. *p<0.05, **p<0.01, ***p<0.001 KO versus WT mice, ^###p<0.001, ^##p<0.01, and ^#p<0.05 versus WT C, ^§§§p<0.001 and ^§§p<0.01 versus LPS-only, ⁺⁺⁺p<0.001, and ⁺⁺p<0.01 versus HV_T MV-only.