Platonin mitigates lung injury in a two-hit model of hemorrhage/ resuscitation and endotoxemia in rats

BACKGROUND: Traumatic hemorrhagic shock and subsequent resuscitation may promote bacteria translocation and cause endotoxemia, a two-hit process that will induce severe lung injury. The pathogenesis involves oxidative stress, neutrophil infiltration, and inflammatory response. Platonin, a potent antioxidant, possesses potent anti-inflammation capacity. We sought to elucidate whether platonin could mitigate acute lung injury in a two-hit model of traumatic hemorrhage/resuscitation and subsequent endotoxemia. METHODS: Adult male rats were randomized to receive traumatic hemorrhage/resuscitation plus lipopolysaccharide (HS/L) alone or HS/L plus platonin (200 μg/kg; n = 12 in each group). Sham groups were used simultaneously. At 6 hours after resuscitation, rats were killed and the levels of lung injury were assayed. RESULTS: Rats treated with HS/L alone had severe lung injury as evidenced by significant alterations in lung function (i.e., arterial blood gas and alveolar-arterial oxygen difference) and histology. Significant increases in polymorphonuclear leukocytes/alveoli ratio (neutrophil infiltration index) and significant increases in the concentrations of inflammatory molecules (including chemokine, cytokine, and prostaglandin E2) and malondialdehyde (lipid peroxidation index) revealed that HS/L caused significant oxidative stress, neutrophil infiltration, and inflammatory response in rat lungs. Moreover, our data revealed that the levels of functional and histologic alteration as well as polymorphonuclear leukocytes/alveoli ratio and the concentrations of inflammatory molecules and malondialdehyde in rats treated with HS/L plus platonin (200 μg/kg) were significantly lower than those treated with HR/L alone. CONCLUSIONS: Platonin mitigates lung injury in a two-hit model of traumatic hemorrhage/resuscitation and endotoxemia in rats.