[The effects of the active constituents of Alisma orientalis on renal stone formation and bikunin expression in rat urolithiasis model].

OBJECTIVE: To evaluate the effects of the active constituents of Alisma orientalis on the expression of bikunin mRNA in rat urolithiasis model, and explore the mechanism of this traditional Chinese medicine on prevention of urinary calculi.

METHODS: Modern phytochemistry and bioactivity guided isolation techniques were applied to extract the active constituents of Alisma orientalis. Hyperoxaluria and the renal oxalate calcium stone formation were induced in rats by infusion into the stomach with 1% ethylene glycol and 2% ammonium chloride. 30 adult male Wistar rats were randomized into 3 groups of 10 rats: control group, infused into the stomach with running water; stone-forming group, infused into the stomach with 1% ethylene glycol and 2% ammonium chloride so as to make into renal oxalate calcium stone model; and group of Alisma orientalis, infused into the stomach with 2% ammonium chloride and the constituents of Alisma orientalis. Four weeks after the rats were killed and their kidneys were taken out. Reverse transcription polymerase chain reaction technique was used to examine the bikunin mRNA expression levels in the rat renal tissues. The calcium oxalate deposits in the kidneys were detected by microscopy. The serum creatinnine and blood urea nitrogen levels, renal tissue calcium content, 24 h urinary calcium and oxalate excretion were also detected.

RESULTS: In the group administered with the active constituents of Alisma orientalis, calcium oxalate deposits in the kidney, serum creatinnine and blood urea nitrogen levels, the bikunin mRNA expression levels, renal tissue calcium content and 24 h urinary calcium excretion were all significantly lower than those in the model group (the bikunin mRNA expression levels: 0.53 +/- 0.17 vs 0.71 +/- 0.25, P < 0.05; renal tissue calcium content: 4.70 mg/g +/- 0.08 mg/g vs 9.49 mg/g +/- 0.45 mg/g, P < 0.01; 24 h urinary calcium excretion: 37 micromol +/- 2 micromol vs 62 micromol +/- 2 micromol, P < 0.01).

CONCLUSION: The active constituents of Alisma orientalis can down-regulate the bikunin mRNA expression, decrease the calcium oxalate formation in rat kidney, and inhibit the renal stone formation in rat urolithiasis model.