Therapeutic effect of glucocorticoid on experimental crescentic glomerulonephritis

Crescentic glomerulonephritis shows active and progressive glomerular changes with rapid deterioration in kidney function. A large dose of glucocorticoid (pulse therapy) is clinically used for the treatment, but its efficacy has not been fully estimated. In this study we assessed the therapeutic effect of a large dose of methyl-prednisolone (MP) on a rat model of crescentic glomerulonephritis that had been induced in WKY rats by an injection of anti-glomerular basement membrane antibody. The infiltration of CD8+ cells and monocytes was manifest by day 3, proteinuria appeared on days 4 and 5, and cellular crescents were diffusely formed by day 7. The gene expression of MCP-1, a chemokine for monocytes and T lymphocytes, was enhanced within 4 hours and peaked on day 3. Daily administration of MP (30 mg/kg/d) from day 3 through day 6 reduced the gene expression of MCP-1 and the numbers of glomerular leukocytes and largely prevented both crescent formation and proteinuria. When daily MP treatment started on day 7, the numbers of glomerular CD8+ cells and monocytes, crescents, and urinary protein were significantly reduced by day 11. In addition, continuing treatment with a small dose of MP (3 mg/kg/d) begun on day 11 completely prevented the increase in blood urea nitrogen and serum creatinine levels. These results indicate that treatment with a large dose of MP histologically and clinically ameliorates crescentic glomerulonephritis in a rat model, supporting the efficacy of pulse MP therapy for the treatment of the disease in human subjects.