Oxalate crystal deposits in renal tubules and cystic changes in 5/6 nephrectomized and normal rats.

Although the mechanism responsible for the genesis of acquired renal cysts in hemodialysis patients has not been clearly defined, the authors suggested that obstruction of the nephron by deposition of oxalate crystals may be an important factor. The present study was undertaken to examine this possibility in an experimental setting. Ten 5/6 nephrectomized rats were given daily subcutaneous injections of 5 mg sodium oxalate and allowed free access to saccharin sweetened water containing 2 mg/ml sodium oxalate. Six other 5/6 nephrectomized rats were controls. In addition, eight healthy rats received 10 mg sodium oxalate for 30 days. The earlier appearance and severe degree of tubular dilatation in oxalate-treated 5/6 nephrectomized compared with untreated 5/6 nephrectomized rats and the presence of renal tubular dilatation with oxalate deposits in normal rats treated with oxalate sodium are likely to be due to tubular obstruction or stenosis caused by oxalate deposition. In conclusion, oxalate deposits in the renal tubules seem to be an important factor in the formation of acquired renal cysts in chronic renal failure.