Estudo das alterações renais induzidas pelos meios de contraste de alta e baixa osmolalidade

Abstract

Iodinated contrast media (ICM) is important in current medical practice during diagnostic and therapeutic interventions. Nephropathy induced by contrast medium (CMIN) is the third iatrogenic cause of acute renal failure in hospitalized patients. The objective of this work was to study the renal effects of contrast media meglumine and ioxitalamato Iobitridol and may contribute to the discovery of pharmacological tools and / or elucidate the mechanisms of nephrotoxicity. The effects of contrast media ioado (MCI) were evaluated on male Wistar rats housed in metabolic cages, every 24 hours for a period of 72 hours after the administration of intravenous contrast. In the control group was administered saline, while groups received ioxitalamato meglumine (high osmolality) and Iobitridol (low osmolality). We analyzed daily urine output, water intake and food. Renal function was assessed by perfusion of isolated rat kidney after 72 hours of administration of the MCI , where perfusion was performed with Krebs Henseleit modified 6g% bovine albumin. Data were compared by ANOVA and Bonferroni test, with significance of p <0.05. The water intake increased in the group treated with high-osmolality contrast (mL/24hs 26.00 ± 2.00) compared to the control group (19.00 ± 1.175 mL/24hs) at the time of 24 hours. Diuresis contrast the group treated with high osmolality (6.84 ± 0.767 mL/24hs), at 24 hours, increased significantly when compared to controls (3.57 ± 0.696 mL/24hs). Perfused isolated rat kidney, we observed an increase in perfusion pressure (PP) in the groups receiving high contrast (98.40 ± 2.467 mmHg *, p <0.05) and low osmolality (126.8 ± 0.936 * mmHg, p <0.05) when compared to the control group (89.13 ± 0.818 mmHg) at the time of 30 minutes. The glomerular filtration rate was reduced in the groups of high osmolality (0.297 ± 0.039 mm.g-1.min-1 **, p <0.05) and low osmolality (0.390 ± 0.053 mm.g-1.min-1 ** p <0.05) when compared with controls (0.741 ± 0.042 mm.g-1.min-1) at time 120 minutes. Regarding the transport of electrolytes was observed for the percentage of tubular transport of chloride in the group of low osmolality (72.41 ± 0.892% MCI-) compared with control groups (83.68 ± 0.951% MCI-) and high osmolality (79.72 ± 1.335%-TCL), in time of 120 minutes, in relation to the tubular transport of potassium was observed a reduction in high-osmolality group (53.86 ± 5.847% TK +) compared to control groups (79 64 ± TK + 1.710%) and low osmolality (69.34% ± 2.479 TK +) at the time of 120 minutes. Histological analysis kidneys receiving high contrast and low osmolality in time of 72 hours, an intense deposition was observed in all cylindrical tubules both the cortex and spinal cord. The glomeruli showed no deposition. In MDCK cell culture cytotoxicity was evident contrasts of high and low osmolality, with a predominance of apoptosis by flow cytometric evaluation. The results demonstrate that the high contrast and low osmolality induce changes in the metabolism of rats daily and vascular parameters assessed in the kidney and kidney perfusion isolated and have cytotoxic activity on MDCK cells.