Abstract: Objective To investigate the expression and significance of the Aquaporin (AQP) 1, 5 in the LPS-induced lung injury in rats. Methods 48 Wistar rats were divided into control-group, ALI-group. Preparation with acute lung injury (ALI) model by intravenous injection of LPS in rats, control-group injected saline. Rats were sacrificed in 2, 6, 12 and 24h, and the samples were collected after the successful modeling. Observing lung HE staining morphological, determining lung wet/dry weight ratio (W/D) and lung permeability index, ELISA detecting serum TNF alpha, MIP-1 alpha level. At the same time, analysis AQP1, AQP5 protein and mRNA content changes through Western-blot, Immunohistochemistry and Real-Time PCR method. Results Compared with control-group, the TNF alpha, MIP-1 alpha level in ALI-group were significantly elevated at 2, 6 and 12h(P<0.05), and to 24h point gradually down to normal level. HE staining showed that the alveolar and interstitial edema and inflammatory cell infiltration after LPS injection 2h, most obviously in 12h. The lung W/D, BALF protein and pulmonary permeability index in ALI-group were significantly higher than those of the control-group (P<0.05), and reached the peak in 12h. At the same time, the expression levels of AQP1, AQP5 in ALI-group were significantly lower than that in control-group (P<0.01). The correlation analysis showed that the expression of AQP1 and AQP5 mRNA was negatively correlated with the lung W/D ratio, serum TNF alpha and MIP-1 alpha level. Conclusion LPS can induces rats acute lung injury, The formation of pulmonary edema may be related to the down-regulation of AQP1 and AQP5.

Key words: Aquaporins, Lung injury, Lipopolysaccharide, Rats