MPO and acute respiratory distress syndrome: Both MCR and purified paeonol were capable of attenuating LPS-induced ALI in rats by eliminating expression of myeloperoxidase (MPO) activity, iNOS, interleukin-1β (IL-1β), interleukin-6 (IL-6) and macrophage-inflammatory peptide-2 (MIP-2) [9,10].