ABSTRACT
<p><b>OBJECTIVE</b>To explore the protective mechanism of Nervilia fordii (NF) by observing the effect of its pretreatment on lung aquaporin 1 and 5 (AQP-1, AQP-5) expression in rats with endotoxin-induced acute lung injury (ALI).</p><p><b>METHODS</b>Twenty-four SD rats were randomly divided into 3 groups, the normal group (A), the NF pre-intervention group (B) and the endotoxin model group (C). Rats in Group B and C were made into ALI by endotoxin (5 mg/kg) injection via sublingual vein, and NF pretreatment was applied to Group B. Animals were sacrificed at the 8 h after modeling, their lung were taken for observing the water permeability change by wet/dry weight ratio (W/D) measuring, pathological feature by HE staining, and the expression of AQP-1, AQP-5 was detected by immunohistochemistry and RT-PCR.</p><p><b>RESULTS</b>The W/D ratio of lung was higher in model rats than in normal rats, but as compared with Group C, it was significantly lower (P < 0.05) in Group B. The pulmonary edematous change was significantly mild and the AQP-1 and AQP-5 protein expressions were significantly higher in Group B than in Group C (P < 0.05).</p><p><b>CONCLUSION</b>NF pretreatment can promote lung AQP-1 and AQP-5 expression up-regulation, increase lung water clearance and transportation to improve the water balance and eliminate pulmonary edema, so as to effectively protect lung from acute injury.</p>