Hydrogen Inhalation Decreases Lung Graft Injury in Brain-dead Donor Rats

Background: The process of brain death induces acute lung injury in donors and aggravates ischemia-reperfusion injury (IRI) in grafts. Hydrogen, a new anti-oxidant, attenuates IRI in several organ transplant models. We examined whether 2% inhaled hydrogen would show favorable effects on lung grafts from brain-dead donor rats.

Methods: Brain-dead donor rats inhaled mixed gases with either 50% oxygen and 50% nitrogen or mixed gases with 2% hydrogen, 50% oxygen and 48% nitrogen for 2 hours. The recipients inhaled the same gas as the donors and were euthanized 2 hours after lung transplantation.

Results: Hydrogen improved PaO(2)/FIO(2) and PVO(2)/FIO(2) from the arterial and pulmonary venous blood in recipients and decreased the lung injury score in grafts from brain-dead donors. Hydrogen decreased the amount of IL-8 and TNF-α in serum, inhibited the activity of malondialdehyde and myeloperoxidase, and increased the activity of superoxide dismutase in the lung grafts from brain-dead donors. Furthermore, hydrogen decreased the apoptotic index of the cells and inhibited the protein expression of intercellular adhesion molecule-1 and caspase-3 in lung grafts from brain-dead donors.

Conclusions: Hydrogen can exert protective effects on lung grafts from brain-dead donors through anti-inflammatory, anti-oxidant and anti-apoptotic mechanisms.