[Effect of etidronate disodium (EHDP) on calcium oxalate renal stones induced by synthetic 1 alpha(OH) vitamin D3 and ethylene glycol in rats].

Combination of 1 alpha(OH) D3(vit D) and ethylene glycol induced renal or ureteral stones or both consisting of calcium oxalate in male Wistar rats. This study investigates the effect of EHDP on calcium oxalate stone using the rat model. EHDP reduced the frequency of renal stone and calcium content in the kidney, and reduced the size of the stones in the renal pelvis and ureter. EHDP biochemically ameliorated renal injury induced by vit D and ethylene glycol. EHDP suppressed urinary excretion of calcium even though serum calcium slightly increased. EHDP had a phosphaturic action. EHDP elevated urinary excretion of magnesium. However, the severity of hypermagnesuria decreased in the rat which was not given EHDP concomitantly. Although EHDP slightly elevated urinary excretion of oxalate in the control rat, it did not affect the high level of urinary oxalate in the vit D/ethylene glycol rat. EHDP did not produce any histological change in the kidney or femoral bone. These data indicate that EHDP can suppress renal stone formation in the vit D/ethylene glycol rat. It is speculated that firstly, EHDP may physicochemically inhibit stone formation in the process of nidus, aggregation and crystal growth of calcium oxalate, under the supersaturated condition of calcium oxalate in the urine, and secondly, EHDP may endocrinologically inhibit production of 1,25 (OH)2 vit D in the kidney or inhibit 1, 25 (OH)2 vit D-mediated intestinal calcium absorption. It is suggested that in order to prevent stone recurrence, EHDP may be clinically applied not only to calcium phosphate stones but also to calcium oxalate stones and hypercalciuria mediated by an active form of vitamin D.