The expression and significance of aquaporin 1 and aquaporin 5 in alveolar epithelia in hyperoxia induced CLD in newborn rats

Objective To study the rules of dynamic changes of auquaporin AQP_1 mRNA and AQP_5 mRNA in the lung tissues with hyperoxia induced lung injury and their roles in pulmonary edema. Methods Three hundred and twenty newborn rats were divided into 4 groups according to oxygen concentrations (FiO_2): Group 1 (FiO_2=0.8), Group 2 (FiO_2=0.6), Group 3 (FiO_2=0.4) and Room-air Control Group (FiO_2=0.21). Rats were sacrificed at 1st, 3rd, 5th, 7th and 14th day after being treated with different concentrations of oxygen or air. The expression of AQP_1 mRNA and AQP_5 mRNA were measured by RT-PCR method. The level of Evans blue in lung tissue were also measured. Results Compared with room air control group, the level of Evans blue in hyperoxic groups increased significantly and it increasing with the durations of oxygen exposure and the concentrations of oxygen.The expressions of AQP_1 mRNA after three days of hyperoxia and AQP_5 mRNA after five days of hyperoxia were lower in all hyperoxia groups than those in control group. Among three hyperoxia groups the expression of AQP_1 mRNA and AQP_5 mRNA decreased with the increase of oxygen concentration (F_1=53.004,P=0.008;F_2=16.617,P=0.01). Conclusions The expression of AQP_1 mRNA and AQP_5 mRNA decreases in hyperoxia induced lung injury and correlated closely with the severity of pulmonary edema.