Lung perfusion with clarithromycin ameliorates lung function after cardiopulmonary bypass

Background. Macrolides antibiotics may affect neutrophil functions that correlate with the inflammation induced by cardiopulmonary bypass. Our study observed the protective effect of clarithromycin on inflammatory lung injury after cardiopulmonary bypass. Methods. Twelve adult sheep were randomly divided into two groups. After cardiopulmonary bypass was established, the lung was perfused through the pulmonary artery with either dextran solution (30 mL/kg) in the control group (n = 6) or dextran solution added to clarithromycin (10 mg/kg) in the experimental group (n = 6). Bypass was withdrawn after 90 minutes. Pulmonary function was determined and inflammatory factors were analyzed. Apoptotic neutrophils in the lung were assayed and lung biopsies were also performed. Results. Pulmonary vascular resistance (102.2 +/- 14.0 dyne.s.cm(-5)) was lower in the experimental group compared with the control group (202.6 +/- 47.3 dyne.s.cm(-5), p < 0.01) whereas the oxygen index was higher in the experimental group (p < 0.05). Plasma myeloperoxidase in the experimental group (0.015 +/- 0.006 U/L) was lower than that in the control group (0.029 +/- 0.007 U/L, p < 0.01). Plasma interlukin-8 (0.18 +/- 0.04 ug/L) and tumor necrosis factor (1.00 +/- 0.13 ug/L) in the experimental group were lower than in the control group (0.39 +/- 0.09 ug/L, 1.55 +/- 0.35 ug/L, p < 0.01). Histologic analyses showed intra-alveolar hemorrhage and neutrophil accumulation in the control group, whereas there were no significant changes in the experimental group. The apoptosis rate of accumulated neutrophils was significantly lower in the control group (p < 0.01). Conclusions. Lung perfusion with hypothermic protective solution containing clarithromycin distinctly inhibits inflammatory responses caused by cardiopulmonary bypass and ameliorates lung function.