Repair of the injured renal papillary tissue in rats.

Renal papillary necrosis was produced in rats by administration of 2-bromoethylamine hydrobromide. The rats drank either 0.9 per cent sodium chloride solution or distilled water, and structural restoration of renal papilla and effect on urine-concentrating ability were examined. All rats drinking distilled water had no evidence of structural restoration of the injured papilla and no significant improvement of urine-concentrating ability. When rats started drinking 0.9 per cent sodium chloride solution shortly after indution of the necrosis, enhanced cellular reconstitution of the necrosed papillary tissue and partial restoration of urine-concentrating ability occurred in a significant number of rats. The most successful structural reparation was the collecting tubules, followed by the thin loops of Henle and the capillaries. Repopulation of the interstitial cells was the least successful. In conclusion, repair of necrosed renal papilla was enhanced when rats drank 0.9 per cent sodium chloride solution starting shortly after injection of renal papilla-necrotizing dose of 2-bromoethylamine hydrobromide.