IMMUNOHISTOCHEMICAL QUANTITATION FOR EXTRACELLULAR-MATRIX PROTEINS IN RATS WITH GLOMERULONEPHRITIS INDUCED BY MONOCLONAL ANTI-THY-1.1 ANTIBODY

Extracellular matrix proteins (type I collagen and fibronectin) in frozen histologic sections of kidney cortex from rats with glomerulonephritis induced by a single intravenous administration of anti-Thy-1.1 antibody were quantified using an immunohistochemical micromethod. Type I collagen and fibronectin contents in renal cortex of rats with experimental glomerulonephritis (4.33 +/- 0.79 and 10.41 +/- 2.01 mu g/mg of total protein, respectively) were 262% and 151%, respectively, higher than in control rats given normal mouse IgG(1.65 +/- 0.16 and 6.88 +/- 0.95 mu g/mg, respectively; p < 0.01 in each case). In the glomerulonephritic rats, the increase in the contents of extracellular matrix proteins, especially type I collagen, correlated with increasing glomeruli with expansion of mesangial areas. The increase in type I collagen content correlated well with increasing urinary protein excretion and blood urea nitrogen and serum total cholesterol levels (r = 0.851, 0.812, and 0.837, respectively; p < 0.05 in each case). The decrease in creatinine clearance correlated with increasing content of type I collagen (r = 0.781; p < 0.05). The immunohistochemical micromethod may make it possible to evaluate the histopathological diagnosis of mesangial proliferative glomerulonephritis quantitatively.