Participation of Cytokines in Proliferation of Mesangial Cells

Immunohistochemistry using monoclonal antibody to rat macrophage identified infiltrating macrophages in mesangial cell proliferative glomerular lesions induced by intravenous administration of an antibody against mesangial cell and suggested a role for macrophage-derived cytokines on the proliferation of mesangial cells. Production of tumor necrosis factor (TNF) and interleukin 1 (lL-1) was enhanced in culture medium of the glomeruli isolated from rat kidneys with the mesangial cell proliferative lesions. Further, recombinant TNF, IL-1 and culture medium of lipopoly-saccharide-silica-stimulated rat macrophages promoted a proliferative response in quiescent rat mesangial cells in culture especially when fetal bovine serum was concomitantly present. However, the gel chromatographic profile of the stimulated macrophage culture medium demonstrated a different peak and therefore, different molecular weight of mesangial cell proliferation-promoting activity compared to the peaks of TNF and IL-1 activities. These findings suggested that TNF and IL-1 as well as other factor(s) derived from macrophages enhanced proliferation of mesangial cells in the glomerulus