In a mouse model of SBP, HAL exposure did not reduce lung injury or bacterial burden after vinblastine-induced neutropenia. CD-1 mice were inoculated intranasally with 40 plaque-forming units A/PR/8/34 influenza virus (SBP) or mock infected (mock). Mock-HAL and SBP-HAL mice (white bars) were exposed to 2% HAL for 2 h just before infection (day 0) and again for 2 h on day 4 PVI. Mock-cont and SBP-cont mice (black bars) received ketamine sedation. On day 2 PVI, mice were administered 5 mg/kg vinblastine to induce neutropenia. On day 6 PVI, mice were inoculated with 2.5 × 106 CFU EF3030, and at 3 h PBI or 24 h PBI, mice were killed, BAL was performed, and lungs were harvested. As an indication of successful neutropenia, (A) the number of neutrophils (PMNs) recovered by BAL on day 6 PVI and 3 h PBI were markedly reduced in all injury groups. On day 7 PVI, 24 h PBI, (B) there was no difference in clinical score or (C) BAL (albumin) between all injury groups. (D) Bacterial burden was higher in the influenza-infected mice, and HAL exposure had no effect (CFU). (E) There was no effect of influenza or HAL exposure on PMN recruitment into the lungs. Sample sizes are displayed above groups. *P < 0.05 SBP-HAL compared with SBP-cont. Data are expressed as mean ± SEM. BAL = bronchoalveolar lavage; CFU = colony-forming units; cont = control; EF3030 = Streptococcus pneumoniae; HAL = halothane; PBI = postbacterial infection; PMN = polymorphonuclear cell; PVI = postviral infection; SBP = secondary bacterial pneumonia.
