Lung inflation with hydrogen sulfide during the warm ischemia phase ameliorates injury in rat donor lungs via metabolic inhibition after cardiac death.

Abstract

Hydrogen sulfide attenuates lung ischemia-reperfusion injury when inhaled or administered intraperitoneally. This study investigated the effects of lung inflation with H₂S during the warm ischemia phase on lung grafts from rat donors after cardiac death. One hour after cardiac death, donor lungs were inflated in situ for 2 h with either O₂ or H₂S (O₂ or H₂S group) during the warm ischemia phase or were deflated as a control procedure (n = 8). After 3 h of cold preservation, lung transplantation was performed. During the warm ischemia phase, the metabolism and mitochondrial structures of donor lungs were analyzed. Arterial blood gas analysis was performed on the recipients. Protein expression in the graft of nuclear factor E2-related factor (Nrf)2 and nuclear factor kappa B (NF-κB) was analyzed by Western blotting, and static compliance, inflammation, oxidative stress, and cell apoptosis were assessed after 3 h of reperfusion. When the O₂ and H₂S groups were compared with the control group, the mitochondrial structures were improved, and lactic acid levels, inflammation, oxidative stress, and cell apoptosis were significantly decreased; and glucose levels, as well as graft oxygenation and static compliance were increased. Simultaneously, the above indices showed further improvements, and the Nrf2 protein expression was significantly greater, and NF-κB protein expression was less in the H₂S group than the O₂ group. Lung inflation with H₂S during the warm ischemia phase inhibited metabolism in donor lungs via mitochondrial protection, attenuated graft ischemic-reperfusion injury, and improved graft function through NF-κB-dependent anti-inflammatory and Nrf2-dependent antioxidative and antiapoptotic effects.