RESUMO
To study the protective function against oxygen radicals in the mesangial area, we assessed extracellular superoxide dismutase (EC-SOD) production in mesangial cells (MCs) in vitro. These cells have a major protective function against oxygen radicals in the extracellular space. In two different kinds of culture conditions: "growth medium" with fetal cow serum, and "differentiation medium" with reduced growth factor, and four extracellular matrixes; type I collagen, type IV collagen, laminin and fibronectin, were added to the MC culture. With the difference in the culture media, differentiation medium induced EC-SOD hyper-production associated with the both of the slowing down of cell proliferation and the suppression of IL-6 and IL-8 production. With difference in the extracellular matrix, the presence of type VI collagen and laminin promoted higher production of EC-SOD than fibronectin and type I collagen. Type IV collagen and laminin associated with the physiological condition of the glomeruli promoted EC-SOD production compared with the presence of type I collagen and fibronectin dominantly located in pathological condition. Suppression of EC-SOD production in growth medium along with MC proliferation and chemokine hyper-production compared with production in differentiation medium might mimic reduction of the protective capacity against oxygen radical toxity during mesangial proliferation in the glomerular nephritis. MC proliferation with type I collagen and fibronectin might enhance oxygen radical toxity in the glomeruli, and accelerate glomerular sclerosis through the suppression of EC-SOD production.