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Effect of Lead (Pb) Acute Exposure on the Indicators of Lead Poisoning and Oxidative Stress Parameters in Kidney of Rats
Einsfeld, L1; Conterato, G.M.M2.; Augusti, P.R.2; Somacal, S1; Bochi, V.1; Soares, F.A.A.2; Emanuelli, T.1-2;
1- Depto. Tecnol. e Ciência dos Alimentos, CCR; 2- Depto. Química, CCNE; UFSM. Santa Maria, RS. E-mail: limigranger@yahoo.com.br
Lead exposure has been associated with significant impairment in the renal function and oxidative stress has been recognized as a important mechanism of its toxic effects. The production of reactive oxygen species (ROS) may result in lipid peroxidation and depletion of cell antioxidant systems. The aim of this study was to evaluate the effect of lead acute exposure on renal δ-aminolevulinic acid dehydratase (ALA-D) activity, thiobarbituric acid reactive species (TBARS) levels, glutathione peroxidase activity, and renal damage markers such as plasmatic creatinine and phosphates. Adult male Wistar rats received a single intraperitoneal injection of 0 or 50mg/Kg lead acetate b.w. and were killed 48h later. Kidneys were removed to procedure all measurements. ALA-D activity was measured according Sassa (Enzyme 28:133-145, 1982), GPx according to Paglia & Valentine (J. Lab. Clin. Med. 70:158-169, 1967), and TBARS levels as described by Ohkawa (Anal. Biochem. 95:351-358, 1979). Plasmatic creatinine and phosphate levels were measured by laboratory kits.
ALA-D activity in lead exposed animals decreased significantly when compared to control (0.84 ± 0.16 vs 1.35 ± 0.12 nmol PBG/ h / mg protein, p<0.05). There were no significant differences in TBARS, GPx activity, neither in creatinine or phosphate levels. The results of this study indicate that ALA-D inhibition antecedes the overproduction of ROS in kidney, and maybe an earlier indicator of lead exposure.
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