Effect Of Female Gender Hormones On Lung Epithelial NA+ Channel In Rats With Acute Lung Injury

Objective:to study the effect of 17 -estradiol and progesterone on subunits of lung epithelial sodium channel and on the clearance of alveolar fluid in rats with acute lung injury.Methods:40 immature female SD rats were randomly assigned into 4 groups after intraperitoneal anesthesia:◆normal control group:injected with 8 mL/Kg saline via venous◆acute lung injury model group(ALI):injected with 0.1 mL/Kg oleic acid via venous◆female gender hormone treated group(12h):injected subcutaneously with combined progesterone and 17 -estradiol at 12h before oleic acid injection ,and the ratio of progesterone to estradiol was 750:1.◆female gender hormone treated group(48h):injected subcutaneously with combined progesterone and 17 -estradiol at 48h before oleic acid injection ,and the ratio of progesterone to estradiol was 750:1.All the subjects were sacrificed at 6h of oleic acid injection. The wet/dry ratio ,the lung coefficient were determined and the expression ofα, β,γ-ENaCmRNA were determined by RT-PCR .The changes of lung pathology were observed.Results:1.The wet/dry ratio and the lung coefficient increased significantly(p <0.01) in ALI model group compared with those of normal control group;Female gender hormones which were administered at 12h before oleic acid injection significantly reduced the wet/dry ratio and the lung coefficient(p <0.05),while the hormones administered at 48h was not able to reduce them(p <0.05).2.The lung volume increased markedly in oleic acid model and the lungs became dark red with a little bit bleeding lesions;The extent of pulmonary edema was decreased markedly in hormone treated group(administering at 12h before oleic acid) compared with ALI model group, and most parts of the lungs in hormone treated group became pink ,a few parts are dark red with a small amount of bleeding points;The extent of pulmonary edema was decreased lightly in hormone treated group(administering at 48h before oleic acid) compared with ALI model group,but had no improvement compared with ormone treated group(administering at 12h before oleic acid)3.The expression of all the subunits of ENaC decreased compared with normal control group(p <0.01);The expression ofα-ENaC increased in hormone treated group(administering at 12h before oleic acid) compared with ALI model group(p <0.05); The expression ofβ-ENaC had no change in hormone treated group compared with ALI model group; The expression ofγ-ENaC increased in hormone treated group(administering at 48h before oleic acid) compared with ALI model group.Conclusion:1.Female gender hormones which were administered at 12h before oleic acid injection significantly reduced the wet/dry ratio and the lung coefficient(p <0.05).2.The extent of pulmonary edema was decreased markedly in hormone treated group(administering at 12h before oleic acid) compared with ALI model group.3.The expression ofα-ENaC increased in hormone treated group(administering at 12h before oleic acid) compared with ALI model group(p <0.05); The expression ofβ-ENaC had no change in hormone treated group compared with ALI model group; The expression ofγ-ENaC increased in hormone treated group(administering at 48h before oleic acid) compared with ALI model group.female gender hormones may up-regulate the expression ofα-ENaC and have a role in the clearance of alveolar fluid.