Static lung elastance (Est, L) at day 28. In the control (C) group, saline was instilled intratracheally once a week for 1 month. Emphysema (E) animals received porcine pancreatic elastase intratracheally following the same protocol. After the last instillation, all groups were randomized to receive saline (SAL) and mesenchymal stem cells (MSC, 1-105 cells) derived from bone marrow (BM), adipose tissue (AD), or lung tissue (LD) intravenously (IV) or intratracheally (IT). Values are means × SD of 7 (E) - 30 (C) animals in each group (10 determinations per animal).