Objective    To investigate the effect of poisonous gas produced from the combustion of nonmetal materials on the pulmonary microvascular permeability and the expression of surfactant-associated protein A (SP-A).     Methods    The model of injury from smoke inhalation in SD rat was set up propotionally scaling-down according to real cabin and operator. Thirty-six rats were randomly divide into 6 groups

namely control group

and the groups of 1

6

24 and 72 h

and 7 d following smoke inhalation respectively. The pathological changes in lung tissue were observed

and the lung water content and the index of pulmonary microvascular permeability were examined. The expression of SP-A mRNA in lung tissue were measured by real-time PCR.     Results    Histopathological observation revealed acute lung injury post-exposure

of which the most severe one was at 24 h post-exposure accompanied by significantly increased lung water content (P0.05). The protein content of BALF and serum increased obviously after smoke inhalation

the index of pulmonary permeability in 1 h

6 h and 24 h groups were obviously higher than that of control groups (P0.05)

while the expression of SP-A mRNA in lung tissue was significantly decreased at 1 h

6 h

24 h and 72 h (P0.01).     Conclusion    Pulmonary microvascular permeability and the expression of SP-A can be significantly influenced by the poisonous gas produced by combustion of nonmetal cabin materials

which may induce the disordered function of liquid exchange between pulmonary blood vessel and interstitium

resulting in pulmonary edema and acute lung injury.