Does methylene blue attenuate inflammation in nonischemic lungs after lung transplantation?

Abstract

Objective: To evaluate whether methylene blue (MB) could minimize the effects of ischemia-reperfusion injury in the nonischemic lung on a lung transplantation rodent model. Methods: Forty female Sprague-Dawley rats were divided into 20 donors and 20 recipients. The 20 recipient rats were divided into two groups (n = 10) according to the treatment (0.9% saline vs. 1% MB solutions). All animals underwent unilateral lung transplantation. Recipients received 2 mL of saline or MB intraperitoneally prior to transplantation. After 2 h of reperfusion, the animals were euthanized and histopathological and immunohistochemical analyses were performed in the nonischemic lung. Results: There was a significant decrease in inflammation—neutrophil count and intercellular adhesion molecule-1 (ICAM-1) expression in lung parenchyma were higher in the saline group in comparison with the MB group—and in apoptosis—caspase-3 expression was higher in the saline group and Bcl-2 expression was higher in MB group. Conclusions: MB is an effective drug for the protection of nonischemic lungs against inflammation and apoptosis following unilateral lung transplantation in rats.