Hypoxia-preconditioned mesenchymal stem cell transplantation improves long-term attenuation of bleomycin-induced airway constriction and lung edema. (A) Pulmonary functions were evaluated as enhanced respiratory pause (Penh) values in animals that received normoxia-preconditioned mesenchymal stem cells (NP-MSCs), hypoxia-preconditioned mesenchymal stem cells (HP-MSCs) or phosphate-buffered saline (PBS) for 18 days following bleomycin (BLM) administration on day 3. Whole-body plethysmography was employed and Penh was used as a noninvasive index of airway dysfunction. (B) After sacrificing the mice on day 21, the lung wet-to-dry weight ratio was determined to assess pulmonary edema. Each dot represents an individual mouse with the mean shown for n ≥ 5 per group. *P < 0.05, **P < 0.01. Ctrl, control.