Therapeutic Effect Of Intratracheal Instillation Of Porcine Surfactant In Rats With Sea Water Aspiration Induced Acute Lung Injury

Objective: To establish the model of acute lung injury in rats caused by seawater aspiration. To observer the therapeutic effect of intratracheal instillation of porcine pulmonary surfactant (PPS) in rats with seawater aspiration induced acute lung injury. Methods:1. Twenty-four rats were anesthetized, underwent a tracheotomy, inserted a tracheal cannula and arterial catheter , and randomly assigned to one of two groups: a control group and a model group. The tracheal cannula was connected via a "Y"-adapter to a breathing bypass and a plastic water reservoir, after 9~ 10 seconds of bypass occlusion, the reservoir pathway was opened. The rats of the model group aspirated 2ml seawater/kg body weight, which had been contained in the reservoir. Two minutes later, these rats aspirated 2ml seawater/kg body weight by the same means. Arterial blood gases , respiratory rate and survival rate were observed during the experiment.2. Thirty-four rats were anesthetized, underwent a tracheotomy, inserted a tracheal cannula and arterial catheter, and randomly assigned to one of four groups: a model group and three doses of PPS groups (100mg/kg, 150mg/kg and 200mg/kg) .Acute lung injury was induced in rats by seawater aspiration. The tracheal cannula was connected via a "Y" -adapter to a breathing bypass and a plastic water reservoir, after 9~10 seconds of bypass occlusion, the reservoir pathway was opened. The rats of four groups aspirated 2ml seawater/kg body weight, which had been contained in the reservoir. Two minutes later, these rats aspirated 2ml seawater/kg body weight by the same means. After thirty minutes, the model group intratracheally instilled saline and three doses of PPS groups intratracheally instilled 100mg/kg, 150mg/kg and 200mg/kg of PPS suspension respectively. Arterial blood gases , respiratory rate and survival rate were observed during the experiment.3. At the end of the experiment, lung index, the counts of white blood cell (WBC)and total protein content in bronchoalveolar lavage fluid ( BALF) , pulmonary histopathology were measured. Results:1. No marked change of the parameters was observed in the control group .2. Compared with the rats in the control group, the rats in the model group significantly increased the respiratory rate , decreased PaO2, increased lung index , total protein content and WBC counts in BALF, as well as led to marked changes in the histological appearance of the lungs.3. Compared with the rats in the model group, the rats in three doses of PPS treatment group significantly increased PaO2 , ameliorated the respiratory of rats , decreased lung index and total protein content in BALF, as well as led to improvements in the survival rate and the histological appearance of the lungs.Conclusion:1. An model of acute lung injury in rats caused by seawater aspiration is established successfully.2. Porcine pulmonary surfactant replacement shows therapeutic effect in rats with seawater aspiration induced acute lung injury.