Analysis of pulmonary function and micromechanics structure after 14 days of movement restriction in female rats

ABSTRACT Immobilization is a condition that affects several segments and organic systems, including the respiratory system, leading to structural and functional alterations. The purpose of this study was to analyze pulmonary function and micromechanical structure after 14 days of movement restriction in rats. Fourteen female Wistar rats with body mass between 210±50 g were used, divided into two groups, composed of (n=7) each group: Control (C) and Immobilized (I). The immobilization procedure involved the abdomen (and last ribs), pelvis, hip and knee extension and the ankle in plantar flexion in the two week period. After the immobilization period, an analysis of the pulmonary function was performed using a mechanical ventilator for small animals, flexVent, and alveolar recruitment maneuvers. Subsequently, lung strips were removed from each animal for pulmonary micromechanics analysis. Statistical analysis was performed using the unpaired t test with p<0.05, expressed as mean±standard error of the mean. Group I presented significant changes in the parameters of airway resistance (Raw) Pre RM (C=0.067±0.003 cmH2O.s/mL, I=0.095±0.004 cmH2O.s/mL, p<0.05) and Hysteresivity (η) Pre RM (C=0.203±0.004 cmH2O.s/mL, I=0.248±0.013 cmH2O.s/mL, p<0.05), which returned to their normal values after RM. Raw Post RM (C=0.064±0.003 cmH2O.s/mL, I=0.065±0.004 cmH2O.s/mL, p<0.05) and η (C=0.209±0.005 cmH2O.s/mL, I=0.214±0.007 cmH2O.s/mL, p<0.05). It is concluded that immobilization causes reversible functional changes in the respiratory system after 14 days of movement restriction evidenced by the reduction of RN and η after RM.