Phospholipid changes of pulmonary surfactant in rats with pulmonary edema after seawater drowning

Objective:To observe the phospholipid changes of pulmonary surfactant in rats with pulmonary edema after seawater drowning (PE-SWD).Methods: Rat models of PE-SWD were obtained by injecting seawater (4 ml/kg) intratracheally. Thirty-two male Sprague-Dawley rats were equally randomized into 4 groups: control group, 4 h drowning group, 8 h drowning group, and 16 h drowning group. Bronchoalveolar lavage (BAL) was performed with normal saline at a total dose of 40 ml/kg 4 h,8 h and 16 h after drowning. Total phospholipid (TPL) was analyzed by Bartlett’s method, dipalmitoylphosphatidylcholine(DSPC) by Mason’s method, and total protein (TP) by Coomassie brilliant blue method in bronchial alveolar lavage fluid (BALF). TPL and disaturated phosphatidylcholine(DSPC) were also determined in lung parenchyma and the ratios of DSPC/TPL and DSPC/TP were caculated. Results: The concentrations of TPL in BALF of control group, 4 h group, 8 h group, and 16 h group were (9.1± 1.1), (6.7±2.2), (11.7±1.3) and (9.0±3.0) mg/kg, respectively, and those of DSPC were (2.8±0.6),(1.6±0.7), (3.1±0.5) and (3.1±0.8) mg/kg, respectively.TPL, DSPC, and DSPC/TPL in BALF decreased in 4 h group compared with those of control group (P0.05) and recovered in 8 h group. TPLs in lung parenchyma in control,4 h,8 h and 16 h groups were (100.8±11.3),(101.1±14.5), (102.7±14.5) and (120.4±21.2) mg/kg, respectively, and DSPCs in lung parenchyma were(19.2±3.6),(19.0±6.0),(24.6±6.0) and (23.6±9.0) mg/kg, respectively. There was no significant difference between all groups. TPs in BALF were (14.9±2.7), (47.2±18.3), (35.1±11.6) and (29.6±5.0) mg/kg, respectively. TPs of the drowning groups were higher than those of control group (P0.05). Conclusion: The effective components of pulmonary surfactant are decreased after seawater drowning. Pulmonary edema after seawater drowning may be treated by exogenous pulmonary surfactant replacement therapy.