Low-molecular-weight dextran sulfate prevents experimental urolithiasis in rats.

Background: Low-molecular-weight dextran sulfate was tested on an experimental model of urolithiasis induced in rats. Methods: Male Wistar rats weighing 250 g had a 15-mg calcium oxalate stone surgically placed into the bladder. A group was sham operated, another group was treated by daily intraperitoneal injection of low-molecular-weight dextran sulfate and the other by daily intraperitoneal saline injection. Results: This treatment prevents the growth of exogenous calcium oxalate stone introduced into the bladder and also avoided the formation of secondary stones in the animals. In addition, low-molecular-weight dextran sulfate prevented the aggregation of other ions, such as ammonium, phosphate and magnesium to the calcium oxalate stone placed in the bladder. These effects of the low-molecular-weight dextran sulfate are associated with the presence of the sulfated polysaccharide in the urine. However, the polysaccharide did not adhere to the bladder stone. Possibly, dextran sulfate forms soluble complex with calcium ions dissolved in the urine and therefore prevented calcium salt crystallization. Conclusion: Dextran sulfate, 8000 Da, led to a decrease in calculi glycosaminoglycans in animals treated with dextran, and there was an inhibition in bladder-implanted stones growth.