Reversibility of nephrotoxicity induced in rats by nitrilotriacetate in subchronic feeding studies.

The reversibility of nitrilotriacetate (NTA)-associated nephrotoxicity was investigated by comparing renal tissues from rats fed nephrotoxic levels of NTA for 7 wk with those from rats allowed 5 wk of recovery after the 7-wk exposure. In addition the toxicity of 2% Na3NTA X H2O in the diet (73 mumol/g diet) was compared with that of 1.5% H3NTA (79 mumol/g diet). The two forms of NTA induced comparable renal tubular cell toxicity which was characterized by proximal convoluted cell vacuolation and hyperplasia. These effects were noted in all of the exposed animals although the extent of damage varied. This specific renal tubular cell toxicity was completely reversed during the 5-wk recovery period. Renal pelvic transitional cell toxicity was induced primarily by Na3NTA X H2O. Renal pelvic toxicity was characterized by hydronephrosis, and erosion, ulceration and hyperplasia of the transitional epithelium. All forms of renal toxicity except that accompanying hydronephrosis were reversed when Na3NTA X H2O feeding was discontinued.