Retention of calcium oxalate crystals in renal tubules.

Crystal retention within the renal tubules is essential for nephrolithiasis and the development of urinary stone disease. We studied the mechanisms involved in this process by inducing calcium oxalate crystal deposition within the rat renal tubules and examining them using various microscopic techniques. Crystals appeared to be retained either by attachment to the tubular epithelium or by aggregating with other crystals thus becoming large enough to be retained by their collective size.