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Expression of Ras in cadmium-induced nephrotoxicity
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Abstracts / Toxicology Letters 164S (2006) S1–S324
groups showed normal renal histopathology and almost similar faint stress proteins pattern. In contrast, after mercury HSP25, the major actin-chaperone and HSP72, an inducible cytoprotective stress protein, were moderate in cortical affected tubules. Moreover, by Perls, a histochemical staining, specific for iron, we detected scattered blue deposits inside epithelial tubular cells. Remarkably, after SCH.B pretreatment, HSP25 and HSP72 expressions persisted and were intense in cortical proximal tubules together with a partial morphological recovery. Perls signal was strong in scattered proximal straight tubules together with lysosomal accumulation. Taken together these data suggest that SCH.B pretreatment attenuated HgCl2 -induced nephrotoxicity in rat by the persistence of the tubular expression of specific cytoprotective stress proteins. doi:10.1016/j.toxlet.2006.06.235 P4-03 Expression of Ras in cadmium-induced nephrotoxicity Effects of the natural antioxidant quercetin S´anchez-Gonz´alez P., Vicente-S´anchez C., P´erezBarriocanal F., L´opez-Novoa J.M., Morales A.I. Department of Physiology and Pharmacology (Toxicology), University of Salamanca, Spain Cadmium (Cd) is an ubiquitous environmental toxicant that affects biological systems in various ways. The molecular mechanisms of its toxicity are not yet well defined. We have recently reported in an experimental model of chronic cadmium administration in rats, that quercetin, a potent oxygen free radical scavenger, has a protective effect on cadmium-induced nephrotoxicity. Quercetin’s strong antioxidant activity could be responsible for the protective effect. However, Cd activates multiple signal transduction pathways related to cellular responses to stress. Ras is a member of a family of small GTPases with a great variety of functions including regulation of gene expression and cell proliferation. Our aim in this work was to study the effect of Cd and quercetin on the proliferation related to Ras-mediated signal transduction pathways. Experiments were carried out in male Wistar rats during nine weeks. Rats were distributed in four experimental groups: (1) control rats; (2) Cd (1.2 mg Cd/kg/day s.c.); (3) quercetin (50 mg/kg/day, i.p.); (4) Cd + quercetin (Cd and quercetin at the same doses as in the Groups 2 and 3, respectively). Renal toxicity was evaluated by measuring urinary excretion of proteins, albumin, glucose and enzyme markers of tubular necrosis, as well as plasma concentrations of creatinine and
urea. Renal expression of Ras and Ras activation was assessed by Western blot and immunohistochemistry. Assessment of cell proliferation was evaluated by detection of the Ki67 antigen. Animals that received both Cd and quercetin showed a better renal function than those receiving Cd alone. Cd-induced tubular endothelium lesions were markedly reduced in rats that also received quercetin. On the other hand, Cd increased Ras activation and cell proliferation. Quercetin treatment reduced Ras activation and the number of cells in proliferation. Our results show that suppression of Ras signal transduction pathway activated and cell proliferation by quercetin is associated with the protective effect on cadmium-induced nephrotoxicity. doi:10.1016/j.toxlet.2006.06.236 P4-04 Cytotoxicity of PPAR ligands on renal proximal tubular cell lines Hector Giral 2 , Ricardo Villa-Bellosta 2 , Julia Catalan 2 , Ana Ferrer-Dufol 1 , Victor Sorribas 2 1 Clinical
University Hospital, Toxicology Unit, Zaragoza, Spain; 2 Laboratory of Molecular Toxicology, University of Zaragoza, Spain Peroxisome-proliferator activated receptors (PPAR) are nuclear transcription factors involved in the metabolism of fatty acids and glucose. Several ligands have been synthesized and used pharmacologically to control dislipidemias and insulin resistance, such as fibrates and glitazones, which are common activators of PPAR-alfa and PPAR-gamma, respectively. Several reports have shown the development of apoptosis by different PPAR activators. Because the kidney contains most of the known PPAR isoforms and it is a critical organ in the course of dislipidemias and diabetes, we have tested whether several PPAR activators affected viability of renal cell lines. Three models of proximal tubular cells were chosen: opossum kidney (OK) cells, pig LLC-PK1 cells and murine MCT cells. Each cell line was assayed in Hank’s balanced salt solution (HBSS) with two different PPAR␣ (WY14643 and clofibrate) and two PPAR␥ (pioglitazone and ciglitazone) activators. Total cell death was quantified by the activity of lactate dehydrogenase (LDH) in HBSS: Twelve hours of incubation with 50–150 M WY14643 increased LDH activity, and the effect was maximal at 250 M. Clofibrate, however, did not affect cell viability, even up to 500 M. Ciglitazone increased LDH activity at 10 M and it was maximal at 50 M in all three lines, while pioglitazone did not induce cell death at any of the con-
Abstracts / Toxicology Letters 164S (2006) S1–S324
groups showed normal renal histopathology and almost similar faint stress proteins pattern. In contrast, after mercury HSP25, the major actin-chaperone and HSP72, an inducible cytoprotective stress protein, were moderate in cortical affected tubules. Moreover, by Perls, a histochemical staining, specific for iron, we detected scattered blue deposits inside epithelial tubular cells. Remarkably, after SCH.B pretreatment, HSP25 and HSP72 expressions persisted and were intense in cortical proximal tubules together with a partial morphological recovery. Perls signal was strong in scattered proximal straight tubules together with lysosomal accumulation. Taken together these data suggest that SCH.B pretreatment attenuated HgCl2 -induced nephrotoxicity in rat by the persistence of the tubular expression of specific cytoprotective stress proteins. doi:10.1016/j.toxlet.2006.06.235 P4-03 Expression of Ras in cadmium-induced nephrotoxicity Effects of the natural antioxidant quercetin S´anchez-Gonz´alez P., Vicente-S´anchez C., P´erezBarriocanal F., L´opez-Novoa J.M., Morales A.I. Department of Physiology and Pharmacology (Toxicology), University of Salamanca, Spain Cadmium (Cd) is an ubiquitous environmental toxicant that affects biological systems in various ways. The molecular mechanisms of its toxicity are not yet well defined. We have recently reported in an experimental model of chronic cadmium administration in rats, that quercetin, a potent oxygen free radical scavenger, has a protective effect on cadmium-induced nephrotoxicity. Quercetin’s strong antioxidant activity could be responsible for the protective effect. However, Cd activates multiple signal transduction pathways related to cellular responses to stress. Ras is a member of a family of small GTPases with a great variety of functions including regulation of gene expression and cell proliferation. Our aim in this work was to study the effect of Cd and quercetin on the proliferation related to Ras-mediated signal transduction pathways. Experiments were carried out in male Wistar rats during nine weeks. Rats were distributed in four experimental groups: (1) control rats; (2) Cd (1.2 mg Cd/kg/day s.c.); (3) quercetin (50 mg/kg/day, i.p.); (4) Cd + quercetin (Cd and quercetin at the same doses as in the Groups 2 and 3, respectively). Renal toxicity was evaluated by measuring urinary excretion of proteins, albumin, glucose and enzyme markers of tubular necrosis, as well as plasma concentrations of creatinine and
urea. Renal expression of Ras and Ras activation was assessed by Western blot and immunohistochemistry. Assessment of cell proliferation was evaluated by detection of the Ki67 antigen. Animals that received both Cd and quercetin showed a better renal function than those receiving Cd alone. Cd-induced tubular endothelium lesions were markedly reduced in rats that also received quercetin. On the other hand, Cd increased Ras activation and cell proliferation. Quercetin treatment reduced Ras activation and the number of cells in proliferation. Our results show that suppression of Ras signal transduction pathway activated and cell proliferation by quercetin is associated with the protective effect on cadmium-induced nephrotoxicity. doi:10.1016/j.toxlet.2006.06.236 P4-04 Cytotoxicity of PPAR ligands on renal proximal tubular cell lines Hector Giral 2 , Ricardo Villa-Bellosta 2 , Julia Catalan 2 , Ana Ferrer-Dufol 1 , Victor Sorribas 2 1 Clinical
University Hospital, Toxicology Unit, Zaragoza, Spain; 2 Laboratory of Molecular Toxicology, University of Zaragoza, Spain Peroxisome-proliferator activated receptors (PPAR) are nuclear transcription factors involved in the metabolism of fatty acids and glucose. Several ligands have been synthesized and used pharmacologically to control dislipidemias and insulin resistance, such as fibrates and glitazones, which are common activators of PPAR-alfa and PPAR-gamma, respectively. Several reports have shown the development of apoptosis by different PPAR activators. Because the kidney contains most of the known PPAR isoforms and it is a critical organ in the course of dislipidemias and diabetes, we have tested whether several PPAR activators affected viability of renal cell lines. Three models of proximal tubular cells were chosen: opossum kidney (OK) cells, pig LLC-PK1 cells and murine MCT cells. Each cell line was assayed in Hank’s balanced salt solution (HBSS) with two different PPAR␣ (WY14643 and clofibrate) and two PPAR␥ (pioglitazone and ciglitazone) activators. Total cell death was quantified by the activity of lactate dehydrogenase (LDH) in HBSS: Twelve hours of incubation with 50–150 M WY14643 increased LDH activity, and the effect was maximal at 250 M. Clofibrate, however, did not affect cell viability, even up to 500 M. Ciglitazone increased LDH activity at 10 M and it was maximal at 50 M in all three lines, while pioglitazone did not induce cell death at any of the con-