RESUMO
OBJECTIVE: To evaluate the effect of an aqueous extract of Phyllanthus niruri (Pn), a plant used in folk medicine to treat lithiasis, on the urinary excretion of endogenous inhibitors of lithogenesis, citrate, magnesium and glycosaminoglycans (GAGs). MATERIALS AND METHODS: The effect of chronic (42 days) administration of Pn (1.25 mg/mL/day, orally) was evaluated in a rat model of urolithiasis induced by the introduction of a calcium oxalate (CaOx) seed into the bladder of adult male Wistar rats. The animals were divided into four groups: a sham control (16 rats); a control+Pn (six); CaOx+water instead of Pn (14); and CaOx+Pn (22). Plasma and urine were collected after 42 days of treatment for biochemical analysis and the determination of urinary excretion of citrate, magnesium and GAGs. The animals were then killed and the calculi analysed. RESULTS: The creatinine clearance or urinary and plasma concentrations of Na+, K+, Ca2+, oxalate, phosphate and uric acid were unaffected by Pn or the induction of lithiasis. Treatment with Pn strongly inhibited the growth of the matrix calculus and reduced the number of stone satellites compared with the group receiving water. The calculi were eliminated or dissolved in some treated animals (three of 22). The urinary excretion of citrate and magnesium was unaffected by Pn treatment. However, the mean (sd) urinary concentration of GAGs was significantly lower in rats treated with CaOx+Pn, at 5.64 (0.86) mg/g creatinine, than when treated with CaOx + water, at 11.78 (2.21) mg/g creatinine. In contrast, the content of GAGs in the calculi was higher in the CaOx + Pn rats, at 48.0 (10.4) g/g calculus, than in the CaOx + water group, at 16.6 (9.6) g/g calculus. CONCLUSION: These results show that Pn has an inhibitory effect on crystal growth, which is independent of changes in the urinary excretion of citrate and Mg, but might be related to the higher incorporation of GAGs into the calculi.
Assuntos
Oxalato de Cálcio/antagonistas & inibidores , Cálculos Renais/tratamento farmacológico , Phyllanthus , Fitoterapia/métodos , Extratos Vegetais/uso terapêutico , Cálculos da Bexiga Urinária/tratamento farmacológico , Animais , Ácido Cítrico/antagonistas & inibidores , Cristalização , Glicosaminoglicanos/urina , Cálculos Renais/urina , Masculino , Compostos Organometálicos/antagonistas & inibidores , Fosfatos/sangue , Fosfatos/urina , Potássio/sangue , Potássio/urina , Ratos , Ratos Wistar , Sódio/sangue , Sódio/urina , Ácido Úrico/urina , Cálculos da Bexiga Urinária/urinaRESUMO
The effect of chondroitin sulfate upon the growth of calcium oxalate crystals was measured in vivo by using an experimental model in rats. Adult male Wistar rats were treated by chronic i.p. injections of chondroitin sulfate solutions (1, 5 or 10 mg in 0.3 ml of saline, every 2 days). This treatment led to a dose-dependent increase in the urinary chondroitin sulfate concentration. Urolithiasis was induced by the introduction of a calcium oxalate seed into the bladder of the animals. Urine samples were collected and the calculi formed were removed after 42 days. The chondroitin sulfate concentration have decreased in the lithiasic urines, as compared to controls and higher chondroitin sulfate doses correlated with larger calculi. The presence of chondroitin sulfate in the matrices of stones obtained from chondroitin sulfate-treated animals suggested that there was some adsorption of chondroitin sulfate on to the growth sites of the calcium oxalate crystals. In contrast to the chondroitin sulfate effect observed in vitro, which inhibits the growth of calcium oxalate crystals, our results suggest that in vivo chondroitin sulfate promotes the growth of stones in the urinary tract.
Assuntos
Oxalato de Cálcio/metabolismo , Sulfatos de Condroitina/urina , Cálculos da Bexiga Urinária/induzido quimicamente , Adulto , Animais , Criança , Sulfatos de Condroitina/administração & dosagem , Modelos Animais de Doenças , Humanos , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos , Cálculos da Bexiga Urinária/química , Cálculos da Bexiga Urinária/urinaRESUMO
Cystinuria is a disease characterized by the excessive elimination of cystine and of dibasic amino acids (lysine, arginine, and ornithine) through urine of homozygotes. This study included 6 children complaining of abdominal pain with or without hematuria. The existence of renal radio-opaque lithiasis was confirmed in 5 of them and in the sixth, it was vesical. The clinical and analytic data were practically normal with the exception of the qualitative test of the amino acid urinary excretion that showed increase in urinary excretion of cystine. Likewise, percentages of tubular reabsorption were pathological in all the patients showing values between 35.4% and 74%. The diagnosis of systini-lysinuric lithiasis was established through amino acid excretion study in the six patients which was below normal; it fluctuated between 36% and 74%. Lysine, together with cystine, was the most frequently affected.