Objective To investigate the expression of aquaporin-1( AQP1 ) in visceral and parietal pleura in SD rats and to examine the effect of AQP1 on pleural fluid turnover. Methods Five groups( n = 24 ) of SD rats were randomly assigned to received intrapleural injection of dexamethasone,lipopolysaccharide, erythromycin, hypertonic saline and normal saline, respectively. The AQP1 protein in pleural was detected with immunohistochemistry. The mRNA expression of AQP1 under stimulations at different time points was measured by real time RT-PCR. Results AQP1 was immunolocalized predominantly to the microvessels and mesothelial cells of visceral and parietal pleura. The extent of AQP1expression in parietal pleura was less than that in visceral pleura[ ( 4. 14 ±1. 12) ×104 copy /μg vs ( 7. 43 ±2. 02) ×104 copy / μg, P lt;0. 05] . AQP1 expression increased at all phases in the dexamethasone group andthe hypertonic saline group, whereas decreased in the erythromycin group and the lipopolysaccharide group.Conclusion The stimulations of dexamethasone, lipopolysaccharide, erythromycin and hypertonic saline can significantly change the AQP1 expression in pleura, which indicate that AQP1 may contribute to the accumulation and clearance of pleuritic fluids.