HEALED EXPERIMENTAL RENAL PAPILLARY NECROSIS AND CORTICAL SCARRING IN THE RAT FROM 2-BROMOETHYLAMINE HYDROBROMIDE

Male Sprague-Dawley rats were each given a single subcutaneous injection of an aqueous solution of bromoethylamine hydrobromide (BEA) at dose levels of 80 mg/kg (16 rats), 125 mg/kg (15 rats) and 250 mg/kg (16 rats) or a single subcutaneous injection of water (controls, 15 rats). The dose levels were chosen so as to cause renal papillary injury varying from minor necrotic foci to necrosis and subsequent sloughing of the entire papilla. The animals were killed after 5 months and the kidneys were weighed and examined macroscopically and microscopically for the presence of RPN and cortical scarring. Macroscopically evident RPN occurred in 18 of 43 surviving BEA-treated rats, bilaterally in 16 and unilaterally in 2. Bilateral asymmetry of the extent of sloughing was evident. All kidneys with macroscopic RPN exhibited cortical scarring. Asymmetry of the extent of atrophy and scarring in some animals resulted in a significant unilateral reduction in renal weight and a significant contralateral compensatory hypertrophy. Twenty-three of the 25 BEA-treated rats without macroscopically evident RPN exhibited minor, histologically visible lesions of the renal papillae including necrosis of loops of Henle in the presence of intact collecting ducts. Only 2 of these animals exhibited tiny, unilateral cortical scars, and renal weights did not differ significantly from those of controls. It may therefore be concluded, contrary to certain published proposals: that experimental RPN may be followed by severe renal cortical scarring, reduction in renal size and (in the presence of asymmetrical lesions) compensatory renal hypertrophy, and that necrosis of thin limbs of loops of Henle does not appear to lead to frequent or severe cortical scarring. © 1978 Springer-Verlag.