2.5 | Animal groups
The surfactant-depleted and LPS-injured rats were assigned randomly to one of the following five study groups (n = 5 for each group) and received different intratracheal treatments with a total volume of 2 mL/kg: 1) Control (no treatment); 2) intratracheal treatment with BUD alone (IT-NS-BUD; 0.5 mg/kg BUD in saline, AstraZeneca Taiwan, Taipei, Taiwan); 3) IT-DS-BUD (0.5 mg/kg BUD) in a solution of 10 mg/mL diluted surfactant; Survanta, Abbott Laboratories, Abbott Park, IL, USA); 4) IT-FS-BUD (0.5 mg/kg BUD in a solution of 25 mg/mL full-strength surfactant); 5) intratracheal treatment with full-strength surfactant alone (IT-FS; a solution of 25 mg/mL full-strength surfactant alone). These intratracheal treatments were performed by using a syringe pump to instill the solutions into a side port of the endotracheal tube adaptor for 10 min.