Expression of intercellular adhesion molecule-1 and lymphocyte function-associated antigen-1 on alveolar macrophages in the acute stage of radiation-induced lung injury in rats

We investigated the expression of intercellular adhesion molecule-1 (ICAM-1) and lymphocyte function-associated antigen-1 (LFA-1) on alveolar macrophages and on lung tissue in the early stage of radiation-induced lung injury, Cells in the bronchoalveolar lavage and lung tissue were obtained from rats at various times between 1 and 8 weeks after 20 Gy of Co-60 gamma irradiation of a hemithorax. These specimens were stained immunohistochemically with anti-ICAM-1 and anti-LFA-1 alpha monoclonal antibodies. The expression of these factors was compared with that of a control group, The total number of alveolar macrophages in the bronchoalveolar lavage was significantly reduced from 1 to 3 weeks, and the number of neutrophils was significantly increased 2 and 3 weeks after irradiation. ICAM-1 and LFA-1 expression on alveolar macrophages was significantly increased starting 1 week after irradiation. The expression of ICAM-1 and LFA-1 on lung tissue was not elevated up to 8 weeks after irradiation. In conclusion, the increased expression of ICAM-1 and LFA-1 on alveolar macrophages as early as 1 week after irradiation suggests that adhesion molecules play a role in the development of radiation-induced lung injury. (C) 1997 by Radiation Research Society.