Chulalongkorn Medical Journal


Background : Kidney stone is a chronic disease that is found worldwide. The highprevalence of the kidney stone in Thailand observed in the northeasternpart which was about 16.9%. The pathogenesis of calcium oxalate stoneformation originated from crystallization of calcium and oxalate ions in renaltubular fluid, overgrowth, aggregation and adhesion to renal epithelial cells.The adhesion of CaOx crystals to renal tubular cell is a critical step ofkidney stone formation. It can cause increased oxidative stress and resultin the renal tubular cells damage. Studying in natural products may be analternative way to prevent the pathogenesis of stone formation.Objective : To study the antioxidant potential of Sung Yod sticky rice extract onthe prevention of ethylene glycol-induced renal tissue damage in rats.Methods : Unpolished Sung-Yod sticky rice was extracted. The total anthocyanin andphenolic contents were determined by pH differential method and FollinCiocalteu reagent assay, respectively. The percentage of antioxidantactivity was assessed by DPPH scavenging assay compared withthe standard serial concentrations of ascorbic acid. In in vivo experiment,rats were divided into two groups: ethylene glycol control (EGC) groupreceived normal drinking water for two weeks and SY treated group wasdaily fed SY at the dose of 200 mg/kg by gastric intubation for two weeks.After two weeks, 0.5% ethylene glycol was administered in all groups,and 1% ammonium chloride was fed by gastric intubation for one week.At the end of the experiment, the kidney tissues were collected forhistological study. Oxidative stress, 8 hydroxyguanosine (8-OHG), wasdetermined by immunoperoxidase whereas antioxidant biomarkersincluding superoxide dismutase (SOD) and catalase were observed byWestern immunoblotting.Results : The mean total anthocyanin and total phenolic compounds were19.566 g/g dry weights and 0.295 mg/g dry weight, respectively. The halfmaximal inhibitory concentration of the Sung-Yod sticky rice extract wassignificantly increased at the fifth teen folded compared with ascorbic acid(P < 0.05). Pathological changes of the kidney including tubular dilation,shrinkage of glomerulus and the flattened renal tubular cells in rat werereduced by treatment with Sung Yod sticky rice extract. The number of8-OHG -positive cells decreased in the SY treated group. The expression ofSOD and catalase significantly increased in the SY treated group, ascompared with EGC group.Conclusion : These findings demonstrate that the Sung-Yod sticky rice extract has aprotective effect on the ethylene glycol-induced renal pathology. Thisextract might be beneficial in preventing the cause of kidney stone.


Faculty of Medicine, Chulalongkorn University

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