| Objective:To establish the model of acute lung injury in rats caused by early seawater drowning. Using of the existing equipments of the Fourth Military Medical University and its affiliated hospitals to make an active pulmonary surfactant (PS) preparation. To observe the therapeutical effect in different concentrations and different applications of exogenous PS treatments in this model through the pulmonary function index and inflammatory reaction index and lung histomorphology.Methods:1. Establish the model of acute lung injury in rats caused by early seawater drowning3. Groups and Observation index:24 model rats were randomly divided into 4 groups(n=6, each): one control group with saline treated and three PPS treated groups with different doses(100mg/kg, 150mg/kg, 200mg/kg). 18 model rats were randomly divided into 3 groups(n=6, each): saline lavage group(group S),PPS instillation group(group I) and PPS lavage group(group L). Arterial blood gases and respiratory rate as pulmonary function index at 0min,30min,60min,120min during the experiments, survival rate, TNF-αand TP level in bronchoalveolar lavage fluid (BALF) and lung index(LI) as inflammatory reaction index , light microscopy examination of inferior lobe of right lung periphery specimens and electron microscopy examination of alveolar epithelial cellⅡafter the experiments were determined and performed in different groups, respectively.Result:1. Establish the model of acute lung injury in rats caused by early seawater drowning successfullyAfter seawater inhalation the BR of rats were increased significantly, then were gradually slowed down, but had been remained at a high level(P<0.05).After seawater inhalation the Pa02 of rats were decreased significantly, then were gradually returned, but had been remained at a low level(P<0.05).2. Effects of different concentrations of PPS treatment on model ratsPulmonary function index: Compared with the rats in the control group, the BR after treatment were decreased obviously (P<0.05). The effect of high concentrations groups(PPS150mg/kg and PPS200mg/kg) is better than low concentrations groups(PPS100mg/kg) (P<0.05). The improvement of BR in PPS200mg/kg group is late but better at 120min. The Pa02 at different time points after treatment were increased obviously than the control group at the same time, while the effect of high concentrations groups(PPS150mg/kg and PPS200mg/kg) is better than low concentrations groups(PPS100mg/kg) at 120min(P<0.05).Lung inflammatory reaction index: TNF-αand TP level in BALF,LI were lower in every PPS treated groups, than those in control group(P<0.05),while the effect of high concentrations groups(PPS150mg/kg and PPS200mg/kg) is better than low concentrations groups(PPS100mg/kg) (P<0.05).Lung histomorphology: General observations indicated that after PPS treatment the tissue swelling, diffuse bleeding and consolidation were lightened significantly. HE stain showed that after PPS treatment the alveoli bleeding, leakage and alveo-lar wilt had marked changes, while the effect of PPS200mg/kg group is the best than others. Under transmission electron micr oscope the lung ultrastructure was ba-dly injuried in control group but in the PPS treated groups, especially in PPS200mg/kg group, the lung ultrastructure injury was greatly ameliorated.The survival rates after treatment were increased.3. Effects of different applications of PPS treatment on model ratsPulmonary function index: Compared with the rats in the control group, the BR after treatment were decreased obviously (P<0.05). The effect of group L is better than group I at 30 min (P<0.05), but after 60min all treatment groups had no significant difference (P>0.05).The Pa02 at different time points after treatment were increased obviously than the control group at the same time,while the effect of group L is better than group I at 60min(P<0.05).Lung inflammatory reaction index: TNF-αand TP level in BALF,LI were lower in every PPS treated groups, than those in control group(P<0.05),while the effect of group L is better than group I (P<0.05).Lung histomorphology: General observations indicated that in group L the ti-ssue swelling, diffuse bleeding and consolidation were lightened significantly than group I. HE stain showed that in group L the alveoli bleeding, leakage and alveo-lar wilt had marked changes than group I. Under transmission electron microscope the lung ultrastructure was badly injuried in group S, but in the PPS treated groups, especially in group L, the lung ultrastructure injury was greatly ameliorated.The survival rates after treatment were increased.Conclusion:1. Establish the model of acute lung injury in rats caused by early seawater drowning successfully.2. Solo application of PPS can obviously alleviates lung injury after seawater drowning, different doses have different therapeutic effects.3. The therapeutic effects of PPS lavage is better than PPS instillation.
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