The Changes Of Lung In Simulated Weightlessness In Tail-suspended Rats

ObjectiveTo investigate the effects of simulated weightlessness on lung function, alveolocapillary permeability and cell apoptosis in pulmonary tissues in healthy rats.Methods1 .Experiments were conducted on 40 Sprague-Dawley male rats, divided into 4 groups: suspended for 7d, control of 7d and suspended for 2Id, control of 2Id. Tail-suspension(-30? was used as weightlessness simulation.2.Lung function were studied with animal plethysmography when suspension ended. Test results were compared statistically.3.The permeability index of fluorescein isothiocyanate-dextran (FITC-Dextran) was used to characterize the alveolocapillary permeability and measured.4.The condition of cell apoptosis in pulmonary tissues was detected with in situ death detection.Resultsl.FEVo.3%, peak expiratory flow(PEF) and maximal voluntary ventilation(MVV) tended to decrease, especially FEV0.3% in 7d and MW in 21d decreased significantly (p<0.05). Forced vital capacity(FVC) increased a bit in 7d and decreased a bit in 2Id, but had not a prominent change.Inspiratory resistance(Ri) and expiratory resistance(Re) tended to increase and Ri in 7d increased significantly(p<0.05). Ri in 21 d decreased a bit, but did not change significantly. Compliance of lung(Cl) had not a prominent change.2.The permeability index of 7d tail-suspended rats increased significantly (p<0.01) and that of 21 d also increased significantly(p<0.05), but the permeability index of 2Id tail-suspended rats increased less than that of 7d.3.There were apoptotic cells in pulmonary tissues of rats. The level of cell apoptosis in pulmonary tissues of 7d tail-suspended rats during simulated weightlessness increased significantly(p<0.01), but that of 21 d had not a prominent change(p>0.05).Conclusion1.Simulated weightlessness in tail-suspended rats has certain effects on lung function. FEVo.3%, peak expiratory flow(PEF) and maximal voluntary ventilation(MVV) tend to decrease, especially FEVo.3% in 7d and MVV in 21d decrease significantly. Airway resistance(Raw) tends to increase and inspiratory resistance(Ri) in 7d increases significantly. Compliance of lung(Cl) has not a prominent change.2.The alveolocapillary permeability increases during simulated weightlessness and can recover a bit as simulated weightlessness goes on.3.There are excessive apoptotic cells in pulmonary tissues of 7d tail-suspended rats during simulated weightlessness .