Renal extracellular matrix alterations in lead-treated rats

Although the nephrotoxic effects of lead are well documented, the subcellul ar mechanisms of its action on the kidney remain unclear. The aim of the pr esent work was to investigate the effects of chronic lead exposure on the e xpression of laminin-1 and fibronectin in the kidney of lead-treated rats. Western immunoblotting of the kidney extracts revealed that experimental ex posure to lead resulted in a marked decrease in the intensity of the bands corresponding to laminin-1 and an increase in the intensity of the band cor responding to fibronectin. Immunohistochemical studies demonstrated a weak labelling to laminin-1 and a strong labelling to fibronectin in all renal b asement membranes together with a decrease in their thickness. Other ultras tructural alterations found were a diminution in the amount of endothelial fenestrae, an increased fusion of foot processes in epithelial cells of the glomerulus and the presence of intranuclear inclusion bodies in the proxim al tubule cells. Lead intoxication might be responsible for the above alter ations in the renal extracellular matrix that could play an important role in the pathogenesis of lead nephropathy. Copyright (C) 2001 John Wiley & So ns, Ltd.