Attenuation of lung ischemia-reperfusion injury by rho-associated kinase inhibition in a rat model of lung transplantation.

Background: A signaling pathway of the small GTPase Rho and Rho-associated coiled-coil-forming protein kinase (ROCK), regulates the contraction of endothelial cells. We studied the effects of Y-27632, a specific ROCK inhibitor, to clarify the role of Rho/ROCK in the pathogenesis of ischemia-reperfusion lung injury in a rat model of single-lung transplantation (LTX). Methods: We flushed 5 donor rat lungs with Euro-Collins solution, and 5 donor lungs with Euro-Collins + Y-27632, 0.03 mg/ml, and preserved the lungs for 6 h at 4 degrees C before reperfusion for 4 h. The 5 rat recipients of Y-27632-treated lungs also received a 10-mg/kg bolus of Y-27632 i.p. 30 min before reperfusion. Results: Pretreatment of the donor lungs and recipient rats with Y-27632 prominently suppressed the post-LTX edema, while the permeability index was only slightly decreased. The (1) numbers of neutrophils and macrophages, and (2) tumor necrosis factor (TNF)-alpha concentration, were significantly lower in the bronchoalveolar lavage fluid of treated than untreated lungs. Conclusions: Y-27632 (1) inhibited the migration of inflammatory cells into the alveolar space, (2) decreased the production of TNF-alpha, and (3) attenuated the edema after LTX. Endothelial Rho and ROCK may play an important role in the pathogenesis of post-LTX injury.