Preventive effect of dapsone on renal scarring following mannose-sensitive piliated bacterial infection.

Renal scarring has been thought to occur in the later stages of chronic pyelonephritis. We previously reported that mannose-sensitive (MS) piliated bacteria promoted renal scarring, which was prevented by antioxidants. The preventive effect of diaphenylsulfone (dapsone), which has a scavenging activity on active oxygen species, on renal scarring was examined. Female Sprague-Dawley rats were inoculated with clinical isolates of Serratia marcescens which had both MS and mannose-resistant pili or with recombinant strains which had MS pili on their surface; they were then administered 20 mg/kg of dapsone or not. Dapsone significantly suppressed scarring following infection of the kidney. The bacterial counts in the kidneys were not different in dapsone-treated and nontreated rats. We conclude that dapsone is effective in preventing renal scarring, and it is suggested that the clinical use of this drug may prevent renal scar formation following pyelonephritis.