Endogenous Glucocorticoids Modulate Experimental Anti-glomerular Basement Membrane Glomerulonephritis

The influence of endogenous glucocorticoids (GC) on glomerular injury was studied in a rat model of heterologous anti-glomerular basement membrane (GBM) glomerulonephritis (GN). Sprague-Dawley rats underwent adrenalectomy (ADX) or sham-operation 3 days prior to i.v. administration of both nephritogenic (100 microgram/g) and subnephritogenic (50 microgram/g) doses of sheep anti-rat GBM globulin. Administration of a subnephritogenic dose of anti-GBM globulin resulted in GN in adrenalectomized animals only. Similarly, ADX performed prior to administration of anti-GBM in the nephritogenic dose range resulted in exacerbation of GN compared with sham-operated animals (24 h protein excretion: 190.8 +/- 32.8 versus 42.5 +/- 2.6 mg/24 h; P < 0.005). In ADX animals receiving subnephritogenic doses of anti-GBM injury was manifested by abnormal proteinuria (62.7 +/- 5.8 mg/24 h), accumulation of neutrophils which peaked at 6 h (7.2 +/- 1.37 neutrophils per glomerular cross-section (neut/gcs)) and macrophage accumulation in glomeruli at 24 h (6.8 +/- 1.2 macrophages/gcs). Sham-adrenalectomized animals given the same dose of anti-GBM globulin developed minimal or no glomerular injury: urinary protein excretion (8.7 +/- 1.5 mg/24 h, P < 0.001); neutrophils (0.2 +/- 0.04 neutrophils/gcs, P < 0.001); macrophages (1.2 +/- 0.5 macrophages/gcs, P < 0.001). The increased cellular recruitment to glomeruli in adrenalectomized animals was associated with glomerular endothelial P-selectin expression. P-selectin expression was not detected in sham-operated rats after anti-GBM injection. Complement deposition in glomeruli was minimal in both groups. Physiologic GC replacement of ADX rats receiving subnephritogenic-dose anti-GBM reversed the observed susceptibility to GN development, with urinary protein excretion (7.8 +/- 1.12, P < 0.005) and no detectable P-selectin expression or leucocyte accumulation in glomeruli. These results suggest that endogenous GC modulate heterologous anti-GBM nephritis in rats and that this may be attributable, in part, to regulation of P-selectin expression.