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Title: Study of biomarkers to evaluate the protective effects of antioxidants against manganese neurotoxicity
Author: Santos, Maria Lopes
Advisor: Santos, Ana Paula Marreilha dos
Dias, Deodália Maria Antunes, 1952-
Keywords: Bioquímica
Marcadores biológicos
Teses de mestrado
Defense Date: 2008
Abstract: Manganese (Mn) an essential nutrient for several animal species is required for normal aminoacid, lipid, protein and carbohydrate metabolism. However, chronic exposure to this metal can originate accumulation in the brain, leading to adverse health effects, particularly in the central nervous system. Although the exact mechanism of Mn toxicity is not completely established, several studies indicate that oxidative stress plays a major role in the Mn-induced toxicity process. To avoid overexposure and the consequent neurotoxic effects, people chronically exposed must be monitorized recorring to adequate biomarkers. The aim of this study was to examine the correlation between exposure and effect biomarkers and the possible protective effect of ebselen, a compound with antioxidant properties, against Mn toxicity. In an in vivo assay rats were exposed to several doses of Mn (4 and 8 doses) by intraperitoneal injection of manganese chloride (10.0 mg/kg). The exposure to Mn was evaluated by measuring Mn levels in the brain and blood. Mn levels in brain were increased and significantly different from control (p<0.0001, for both doses). On the other hand, blood levels failed to evidence the accumulation of Mn in the brain in a dose-dependent manner, with only 8 doses group showing significant differences (p<0.0001). The levels of reduced glutathione (GSH) in the brain were assessed as an indirect indicator of oxidative stress and prolactin levels in serum were analyzed. GSH levels were significantly decreased in 8 doses treated animals (p<0.0001). Prolactin was shown to be a valuable indicator of the neurotoxic effects of Mn, since significant and dose-dependent increase was found for both treated groups (p<0.0001). In addition a decrease in motor activity was observed in the 8 doses group. Finally, ebselen evidenced a protective effect against Mn accumulation in the brain, for the 8 doses group (p<0.0001). Yet, it doesn't seem to protect against oxidative stress since decreased values of GSH were observed
Description: Tese de mestrado, Biologia (Biologia Humana e Ambiente), 2008, Universidade de Lisboa, Faculdade de Ciências
Appears in Collections:FC - Dissertações de Mestrado

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