Objective: Pre-B cell colony enhancing factor (PBEF) is an important proinflammatory cytokine involved in acute lung injury. However, whether PBEF participates in lung injury caused by cardiopulmonary bypass (CPB) is still unknown. This study aimed to investigate the effects of silencing PBEF on lung injury and the sodium and water transport system in rats receiving CPB.
Methods: Morphological changes in lung tissues were evaluated using hematoxylin and eosin (H&E) staining. PBEF was detected using immunohistochemistry. The sodium and water transport system-related proteins and cellular signaling pathways were detected by Western blotting.
Results: Rats receiving CPB (model group) had more severe alveolar wall damage and higher expression of PBEF in free form than the control rats. Western blotting showed that the expression of PBEF, surfactant protein D (SP), aquaporin (AQP) 1, AQP5, and epithelial sodium channel (ENaC) was significantly higher in the lung tissue of CPB rats than control rats. By contrast, adenovirus-encoding sh-PBEF significantly reduced the expression of PBEF, SP, AQP1, AQP5, and ENaC in the lung tissues of rats treated with CPB. The phosphorylation levels of extracellular signal-regulated protein kinases 1 and 2 (ERK1/2), protein kinase B (AKT), and p38 mitogen-activated protein kinase (MAPK) were significantly increased in the lung tissue of rats that received CPB, and were downregulated by adenovirus-encoding sh-PBEF.
Conclusion: Adenovirus-encoding sh-PBEF could reduce lung injury and repair the sodium–water transport system in rats receiving CPB, likely through reducing MAPK, ERK1/2, and Akt signaling pathways.
Keywords: pre-B cell colony enhancing factor, epithelial sodium channel, aquaporin, cardiopulmonary bypass