Simvastatin Suppresses Lung Inflammatory Response in a Rat Cardiopulmonary Bypass Model

Background Inflammatory response in the lungs is a well-known complication after cardiopulmonary bypass (CPB). The main aims of our study were to explore whether pretreatment with simvastatin would inhibit toll-like receptor 4 expression and suppress lung inflammatory response in a rat CPB model. Methods Male Sprague-Dawley rats were divided into four groups (n = 6 each): sham group; CPB (control group); CPB plus low-dose simvastatin (5 mg/kg daily [L-Sim group]); and CPB plus high-dose simvastatin (10 mg/kg daily [H-Sim group]). Blood samples were collected at the beginning and at the termination of CPB, and at 1, 2, 4, and 24 hours after operation. The bronchoalveolar lavage fluid and lungs were harvested 24 hours postoperatively. Results The simvastatin-treated groups had significantly higher ratios of PaO 2 /FiO 2 and lower values of respiratory index than the control group. We observed that simvastatin reduced CPB-induced toll-like receptor 4 and nuclear factor-κB expressions in CPB groups ( p p p Conclusions These findings suggest that simvastatin inhibited CPB-induced toll-like receptor 4 upregulation and nuclear factor-κB activation, efficaciously reduing the pulmonary inflammatory response after CPB.