Thrombus formation, hemostasis, adhesiveness of leukocytes and morphological abnormalities in the microcirculation of adjuvant arthritic rats.

Microcirculatory alterations which may be responsible for the chronicity of adjuvant-induced arthritis in the rat were investigated. Thrombus formation in the mesenteric microcirculation was investigated by laser-technique. In arthritic rats thrombus formation for a given stimulus was increased significantly and a correlation was found between the intensity of the arthritic changes and this thrombotic reaction. Adherence of leukocytes to the venous endothelium was studied by an in vivo technique. The number of "rolling" and "sticking" leukocytes was greatly increased in the mesenteric venules of arthritic rats. Acute treatment of severely arthritic rats with aspirin greatly reduced the increased adhesiveness of granulocytes. By the use of an atraumatic technique for vital microscopy of the microcirculation of skin of arthritic rats, striking morphologic changes with stasis of erythrocytes were observed. Morphological aberrations were also found in the mesenteric microvessels of diseased animals.