Content in Toll-like receptor 4 in the membrane fraction of rat alveolar type II cells with or without exposure to smoke and mechanical ventilation. Smoke exposure and mechanical ventilation alone did not lead to a significant increase in TLR4 compared to normal controls. The combination of the two stimuli resulted in a nonsignificant increase in TLR4 compared with both the nonsmoke/nonventilated (NS-NV) and smoke/nonventilated (S-NV) groups (both P < 0.05, not significant after correction for false discovery rate). ATII: alveolar type II cells; NS-V: Nonsmoke/ventilated; S-V: Smoke/ventilated. Bars represent mean and standard deviation of the data.