IMMUNOHISTOCHEMICAL ANALYSIS OF TYPE-III AND TYPE-IV COLLAGENS IN TUBULOINTERSTITIAL DAMAGE IN HUMAN BENIGN NEPHROSCLEROSIS

Prolonged hypertension causes structural changes including glomerulosc lerosis and tubulointerstitial damage of the kidney, termed benign nep hrosclerosis. It is generally accepted that, in benign nephrosclerosis , increased accumulation of extracellular matrix in the glomeruli resu lts in glomerulosclerosis. Little is known, however, about the possibl e role of the extracellular matrix in the tubulointerstitial damage in benign nephrosclerosis. In this study, the possible roles of type IV basement-membrane collagen and type III interstitial collagen in tubul ointerstitial damage caused by hypertension were explored. Immunohisto chemical techniques were used to investigate the distribution of type III and type TV collagens in the kidney sections of is patients with b enign nephrosclerosis with tubulointerstitial damage and in 10 control s, In the control renal sections strong immunostaining for type III co llagen was found in the interstitium and immunostaining for type IV co llagen was present in the tubular basement membrane and weakly in the interstitium. In the patients with tubulointerstitial damage there was increased immunostaining for both type III and type IV collagens in t he expanded interstitium and damaged tubules than was found in the con trol kidney sections. These findings indicate that increased accumulat ion of both type III and type IV collagens might play a significant ro le in the tubulointerstitial damage in benign nephrosclerosis.