Nephrocalcinosis induced by hyperoxaluria in rats

PURPOSE: To investigate nephrocalcinosis due to hyperoxaluria induced by two different inducing agents in rats. METHODS: Forty Sprague-Dawley male rats were randomly distributed into four groups: Group1 (Clinical control, n = 10); Group 2 (0.5% Ethylene Glycol + Vitamin D3, n = 10); Group 3 (1.25% Ethylene Glycol, n = 10); and Group 4 (5%Hydroxy L-proline, n = 10). Five animals from each group were euthanized after one week of follow-up (M1 Moment) and the remaining, after four weeks (M2 Moment). All animals underwent 24h urine dosages of calcium, oxalate, uric acid, citrate and serum creatinine. Histology and histomorphometric analyses were performed using Image J program in the hematoxylin-eosin stains. Calcium deposits in the renal parenchyma were quantified by PIXE technique (Proton Induced X-Ray Emission). RESULTS: 24h urinary parameters did not show any significant variations after 28 days of experiment except by hyperoxaluria that was significantly higher in Group 3. Histomorphometric analyses showed a significantly higher nephrocalcinosis in Group 2 (p<0.01). The calcium deposits in the renal parenchyma were 10 and 100 times higher in Group 2 in comparison to other groups in the M1 and M2 moments, respectively. CONCLUSION: The Group 2 (vitamin D3+Ethylene Glycol 0.5%) was the best model to induce nephrocalcinosis in rats after 28 days.

Avaliaçäo da funçäo tubular proximal utilizando o clearance de lítio no tratamento pela ciclosporina A em ratos / Evaluation of the proximal tubular function using the clearance of the lithium in the treatment by cyclosporine A in rats

Estudamos as alteraçöes renais como o uso da CSA (12,5 mg/kg/d/6 semanas), em ratos Wistar Nx à direita (G1 = controle, n = 12) (G2 = CSA, n = 12). Foram realizados clearances de creatinina (Ccr), lítio (CLi) e estudo histopatológico do rim E. Os resultados näo mostraram alteraçao significativa no Ccr. O CLi caiu significativamente (p < 0,01) no G2. A fraçäo de excreçäo de lítio (FELi) também foi menor neste grupo. A carga filtrada de sódio (CF) näo diferiu entre os grupos. A reabsorçäo fracional proximal de sódio (RFrPNa) foi maior no G2 (p < 0,01), conseqüentemente o aporte distal (AD) caiu (p < 0,01). A RFrD-I e II (distal) foram menores no G2. Estes achados demonstraram alteraçöes funcionais tubulares renais artribuídas à CSA, que näo correspondem às alteraçöes de filtraçäo glomerular ou às alteraçöes morfológicas nestas condiçöes experimentais.