Different effects of mesenchymal stem cells on elastase-induced pulmonary emphysema and macrophages activity in rats

The aim of the study was to assess lung tissue changes and macrophages activity (MA) after mesenchymal stem cells (MSCs) transplantation in elastase model of pulmonary emphysema in rats. Methods: Forty 3-months old Wistar rats were randomized into 4 groups. Control group (group 1) was injected intratracheally 0,4 ml of normal saline, other animals (groups 2-4 ) received one intratracheal injection of 20 units (U) porcine pancreatic elastase in 0,4 ml of saline. Next day (group 2) and 7 day (group 4) rats were intravenously injected 2000000 autologous MSCs in 0,5 ml of saline. Group 4 was used as emphysema control. Before killing on 21-st day rats were undergone peritoneal lavage with analysis of hemi-luminescent macrophages activity in the obtained fluid Results: The lungs of groups 2-4 had various degrees of centriacinar emphysema. There were no significant differences between the sizes of dilated respiratory bronchioles in groups 2 & 4. Only in the 2-nd group we observed the lymphoid infiltration around arterioles. The width of respiratory bronchioles in group 3 was on 41% less than in the 4-th. The Index of hemi-luminescent MA has made 28,8±1,1 U (1 group), 35,8±1,6 U (2 group), 31,9±1,9 U (group 3), 57,3±1,3 U (group 4). Conclusions: MSCs have various effects on damaged lung tissue at different periods of transplantation. MSCs can enhance the local vascular inflammatory response in the early period of elastase injury. More later injection of MSCs can repair the structure of acini in acute model of emphysema in rats.