Accelerated passive Heymann nephritis in rats as an experimental model for membranous glomerulonephritis and effects of azathioprine and prednisolone on the nephritis

Progressive passive Heymann nephritis (group II) was induced in rats by i.v. injections of rabbit antiserum against an antigen from the brush border of the proximal tubules of rat kidney following immunization with rabbit gamma-globulin in Freund's complete adjuvant, and the process of the disease was compared with that of rats that received the antiserum alone (group I). The rats of group I showed proteinuria (30-50 mg/day) and plasma cholesterol content (80-90 mg/dl) slightly higher than the normal level from the 17th or the 22nd day after antiserum injection to the 90th day. The rats of group II revealed a heavy proteinuria (300-400 mg/day) and hypercholesterolemia (approx. 200 mg/dl) during the same period. In group II, there were the thickening of glomerular basement membrane (GBM) and spike formation. Moreover, granular deposits of rat IgG, rabbit IgG and rat C3 were observed along the GBM. These changes were weaker in group I. When given orally, daily, azathioprine (20 mg/kg) and prednisolone (1 and 3 mg/kg) showed a beneficial effect on the nephritis in group II. The group II model closely resembles human glomerulonephropathy and may be useful for studying the effect of medication on glomerulonephropathy.