Evaluation of antiurolithic effect and the possible mechanisms of Desmodium styracifolium and Pyrrosiae petiolosa in rats

Chinese herbs Desmodium styracifolium (Ds) and Pyrrosiae petiolosa (Pp) have been widely used to treat urolithiasis with few side effects in traditional Chinese medicine (TCM). In vitro crystallization study has confirmed their prophylaxis of Calcium oxalate (CaO _x ) stones formation. However, little is known on their possible mechanisms in vivo. In the present study, we proposed to systematically evaluate their antilithic effects and clarify the underlying mechanism of Ds and Pp using a rat nephrolithiasis model and administering the aqueous extracts. Adult male Wistar rats were fed with 5% ammonium oxalate (AmO _x ) forage to induce nephrolithiasis. After 1 week, the rats were randomly divided into eight groups, and given low, medium, and high dose of each herb treatments (275, 550 and 1,100 mg/kg for Ds and 150, 300 and 600 mg/kg for Pp) by gavage for 3 weeks. In contrast to urolithic rats, urinary oxalate significantly reduced, and urinary calcium increased in medium and high dose Ds groups. Few depositions were observed in kidney with slight dilation of tubules and inflammatory infiltration. Osteopontin (OPN), nitric oxide (NO), and malondialdehyde (MDA) levels significantly decreased, but Superoxide dismutase (SOD) activities were enhanced in kidneys. In high dose Pp group, crystals were found in the dilation of tubules with slight inflammatory infiltration. Partial serum and urinary variables returned to the normal range. In conclusion, medium and high dose Ds has beneficial effect in preventing CaO _x stone formation by rising urinary Citrate excretion, decreasing urinary calcium, diuresis, and antioxidative effects. Although high dose Pp has relatively weak prophylaxis, it indicates significant anti-inflammatory and antioxidant effects.