Thiabendazole induces urinary tract toxicity in male ICR mice

Male ICR mice were administered thiabendazole (TBZ) in the diet at concentr ation of 0 (control), 0.8, 1.2 and 1.6% for 44 weeks. The mortality was 10, 6, 40 or 90% in control. 0.8, 1.2 or 1.6% TBZ group, respectively. In dead mice, the gross findings included the abnormalities of kidney such as atro phy, hydronephrosis or swelling in 2, 67, 95 or 96% of the 0. 0.8, 1.2 or 1 .6% TBZ group, respectively. In surviving mice at the end of study, the rig ht kidney weight of treated groups was significantly lower than that of con trol group. The urinary bladder weight of treated groups was significantly higher than that of control group. Gross findings in treated mice included the renal atrophy, hydronephrosis, calculi in renal pelvis or urinary bladd er and thickening of the bladder wall. Microscopic findings in the kidneys of treated mice included nephrosis, hydronephrosis and hyperplasia of trans itional epithelium of renal pelvis and/or papilla. In the urinary bladder, hyperplasia or squamous metaplasia of transitional epithelium were found in treated mice. Administration of TBZ in the diet for 44 weeks results in ne phrosis and calculus formation in the renal pelvis and urinary bladder of m ale ICR mice, and is associated with hyperplasia of transitional epithelium of renal pelvis or urinary bladder. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.