MPO and inflammatory response: In this experiment, 25 ng or 200 ng of recombinant murine IL-6 or vehicle (0.1% BSA) was administered IT to healthy mice and BAL fluid cytokines (IL-6, CXCL-1, TNF-α and IL-1β), lung inflammation (lung IL-6, CXCL-1, TNF-α, IL-1β, and MPO activity) and serum cytokines (IL-6, CXCL-1, TNF-α and IL-1β) were determined at two hours.