Non-neoplastic renal lesions in Sprague-Dawley and Fischer-344 rats

Incidences of non-neoplastic renal lesions in untreated Sprague-Dawley (1540) and Fischer-344 (491) rats were evaluated, tabulated, and compared. In Sprague-Dawley rats, the most frequently occurring lesion was chronic progressive nephropathy (68.5 %) followed by tubular mineralization (30.9 %), pelvic calculi (9.0 %), brown pigmentation of the tubular epithelium (8.8 %), hydronephrosis (5.1 %), tubular dilatation (3.1 %), and vascular mineralization (3.1 %). In Fischer-344 rats, chronic progressive nephropathy (82.0 %) was the most commonly occurring lesion followed by tubular mineralization (38.8 %), vascular mineralization (2.2 %), hydronephrosis (1.6 %), and pelvic calculi (1.4 %). In both strains, other lesions were less frequent.