[Influence of porcine pulmonary surfactant administered at different time on therapeutic effects in rats with oleic acid induced acute lung injury].

ABSTRACT

OBJECTIVE: To investigate the therapeutic effects of endotracheal instillation porcine pulmonary surfactant (PPS) given at different time on acute lung injury (ALI) induced by oleic acid (OA). METHODS: Arterial blood gases and respiratory rate during the experiments, survival rate, lung index, total protein (TP) contents in bronchoalveolar lavage fluid (BALF), tumor necrosis factor-alpha (TNF-alpha) level in plasma, light microscopy of the lung at 4 hours after the experiments were examined in different groups of Sprague-Dawley (SD) rats Group 1, sham group; Group 2, injected intravenously with OA 0.2 ml/kg; Group 3, injected intravenously with OA 0.2 ml/kg+PPS 100 mg/kg 0.5 hour after OA; Group 4, injected intravenously with OA 0.2 ml/kg+PPS 150 mg/kg 0.5 hour after OA; Group 5, injected intravenously with OA 0.2 ml/kg+PPS 100 mg/kg 2 hours after OA; Group 6, injected intravenously with OA 0.2 ml/kg+PPS 150 mg/kg 2 hours after OA. RESULTS: Giving PPS not only improved the rats' (Group 3, Group 4 and Group 6) arterial blood gases and reduced respiratory rate, but also significantly raised their 4 hours-survival rate and decreased lung index, protein contents in BALF and TNF-alpha level in plasma, ameliorated pathohistological changes compared with Group 2 and Group 5 (all P<0.05). CONCLUSION: PPS (100 mg/kg) administered at the early stage (0.5 hour after OA) provides obvious effects on respiratory efficiency and alleviates lung injury in rats with OA induced ALI, PPS (150 mg/kg) at the late stage (2 hours after OA) has the same effects mentioned above, however PPS (100 mg/kg) given 2 hours after ALI has no therapeutic effects.