Objective: To observe the effect and mechanism of lung inflation with both carbon monoxide (CO) and hydrogen (H2) during the cold ischemia phase (CIP) on the inflammatory response in a model of rat lung transplantation.
Methods: Eighty SPF SD rats, aged 8-10 weeks, weighing 250-280 g, including donors and recipients, were randomly divided into four groups: O2 inflation group (group O2), CO inflation group (group CO), H2 inflation group (group H2), and CO combined H2 inflation group (group CH), 10 pairs of rats in each group (one donor and one recipient in each pair). After the donor lungs harvested, they were inflated during the CIP with 40%O2 + 60%N2, 0.05%CO + 40%O2 + 59.95%N2, 3%H2 + 40%O2 + 57%N2, or 0.05%CO + 3%H2 + 40%O2 + 56.95%N2, respectively (5 ml/kg). The mixed gas was replaced every 30 minutes, and lung transplantation was performed 180 minutes later. The blood gas analysis such as PaO2/FiO2, pH, and base excess (BE) was performed before transplantation and 3, 60, 120, and 180 minutes after reperfusion in the recipient. The lung wet/dry ratio (W/D), the myeloperoxidase (MPO), interleukin-6 (IL-6), interleukin-10 (IL-10), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) in lung tissues detected by ELISA, the percentage of neutrophil in bronchoalveolar lavage fluid (BALF), the large surfactant aggregate (LA), small surfactant aggregate (SA), and LA/SA were detected by high-performance liquid chromatography, the pulmonary surfactant associated protein (SP)-A and nuclear factor-κB (NF-κB) protein expression were detected by western blot, and the lung injury score (LIS) were measured by HE 180 minutes after reperfusion.
Results: Compared with group O2, the PaO2/FiO2, pH, and BE 60, 120, and 180 minutes after reperfusion in recipients were significantly increased (P < 0.05), transplanted lung tissue W/D, the concentration of IL-6, IL-1β, TNF-α, and MPO, neutrophil percentage, SA, NF-κB protein content, and LIS were significantly decreased (P < 0.05), while the concentration of IL-10, LA, LA/SA, and SP-A protein content were significantly increased in groups CO, H2, and CH (P < 0.05). Compared with group CO, the PaO2/FiO2, pH, and BE 120, and 180 minutes after reperfusion in recipients were significantly increased in groups H2 and CH (P < 0.05), transplanted lung tissue W/D, the concentration of IL-6, IL-1β, TNF-α, and MPO, neutrophil percentage, SA, NF-κB protein content, and LIS were significantly decreased in group CH (P < 0.05), while the concentration of IL-10, LA, LA/SA, and SP-A protein content were significantly increased in group CH (P < 0.05). Compared with group H2, the PaO2/FiO2, pH, and BE 120, and 180 minutes after reperfusion in recipients were significantly increased (P < 0.05), transplanted lung tissue W/D, the concentration of IL-6, IL-1β, TNF-α, and MPO, neutrophil percentage, SA, NF-κB protein content, and LIS were significantly decreased (P < 0.05), while the concentration of IL-10, LA, LA/SA, and SP-A protein content were significantly increased in group CH (P < 0.05).
Conclusion: The combination of CO and H2 inflation during CIP inhibits the lung graft inflammatory response, and also decreases the NF-κB protein content, increases the SP-A protein content, and maintains the pulmonary surfactant stability. |
