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

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).

CONCLUSIONS

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.