MPO and acute respiratory distress syndrome: The researchers indicated, the BM-MSCs in the ARDS model in rabbits resulted in the decrease in pro-inflammatory cytokines and the increase in anti-inflammatory cytokines in the plasma, similar to BAL, which shows a progressive trend [5], the BM-MSCs transplantation in the ALI model in mice caused the tissue inhibitor expression of metalloproteinase-1 to decline and the increment expression of metalloproteinase-8 [62] and the levels of myeloperoxidase activity and malondialdehyde reduction and the anti-oxidant enzyme activities to increase [67].