IMMUNOHISTOCHEMICAL LOCALIZATION OF AN INDUCIBLE FORM OF NITRIC-OXIDESYNTHASE IN VARIOUS ORGANS OF RATS TREATED WITH PROPIONIBACTERIUM-ACNES AND LIPOPOLYSACCHARIDE

Immunohistochemical localization of an endotoxin-inducible form of nit ric oxide synthase was examined using rabbit polyclonal antibody again st the enzyme purified from rat liver. In rats treated with Propioniba cterium acnes and lipopolysaccharide, immunostaining was observed in m acrophages, occasional lymphocytes, neutrophils and eosinophils in red pulp of spleen, Kupffer cells, endothelial cells and hepatocytes in l iver, alveolar macrophages in lung, macrophages and endothelial cells in adrenal glands, and histiocytes, eosinophils, mast cells and endoth elial cells in colon. Immunoreactivity was also evident in the followi ng tissues: histiocytes and endothelial cells in kidney; histiocytes a nd neutrophils in esophagus; macrophages and eosinophils in duodenum, macrophages, some lymphocytes and mast cells in ileum; histiocytes in thymus; and endothelial cells in heart and aorta. Immunoreactivity was not detected in these organs from untreated rats. Positively staining cells in these rat organs appeared within 2.5 h after lipopolysacchar ide administration; their number dramatically increased within the nex t 2.5 h, remained at high levels for a further 19 h, and then decrease d over the following 24 h. The number of positive cells appearing corr elated well with the nitric oxide synthase activity biochemically dete rmined in the same organs.