RESUMEN
The present study investigated the effects of quercetin in the impairment of memory and anxiogenic-like behavior induced by cadmium (Cd) exposure. We also investigated possible alterations in acetylcholinesterase (AChE), Na(+),K(+)-ATPase and δ-aminolevulinate dehydratase (δ-ALA-D) activities as well as in oxidative stress parameters in the CNS. Rats were exposed to Cd (2.5mg/kg) and quercetin (5, 25 or 50mg/kg) by gavage for 45days. Animals were divided into eight groups (n=10-14): saline/control, saline/Querc 5mg/kg, saline/Querc 25mg/kg, saline/Querc 50mg/kg, Cd/ethanol, Cd/Querc 5mg/kg, Cd/Querc 25mg/kg and Cd/Querc 50mg/kg. Results demonstrated that Cd impaired memory has an anxiogenic effect. Quercetin prevented these harmful effects induced by Cd. AChE activity decreased in the cerebral cortex and hippocampus and increased in the hypothalamus of Cd-exposed rats. The Na(+),K(+)-ATPase activity decreased in the cerebral cortex, hippocampus and hypothalamus of Cd-exposed rats. Quercetin prevented these effects in AChE and Na(+),K(+)-ATPase activities. Reactive oxygen species production, thiobarbituric acid reactive substance levels, protein carbonyl content and double-stranded DNA fractions increased in the cerebral cortex, hippocampus and hypothalamus of Cd-exposed rats. Quercetin totally or partially prevents these effects caused by Cd. Total thiols (T-SHs), reduced glutathione (GSH), and reductase glutathione (GR) activities decreased and glutathione S-transferase (GST) activity increased in Cd exposed rats. Co-treatment with quercetin prevented reduction in T-SH, GSH, and GR activities and the rise of GST activity. The present findings show that quercetin prevents alterations in oxidative stress parameters as well as AChE and Na(+),K(+)-ATPase activities, consequently preventing memory impairment and anxiogenic-like behavior displayed by Cd exposure. These results may contribute to a better understanding of the neuroprotective role of quercetin, emphasizing the influence of this flavonoid in the diet for human health, possibly preventing brain injury associated with Cd intoxication.
Asunto(s)
Acetilcolinesterasa/metabolismo , Ansiedad/prevención & control , Cadmio/toxicidad , Trastornos de la Memoria/prevención & control , Quercetina/farmacología , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Animales , Ansiedad/inducido químicamente , Ansiedad/enzimología , Conducta Animal/efectos de los fármacos , Corteza Cerebral/efectos de los fármacos , Corteza Cerebral/enzimología , Hipocampo/efectos de los fármacos , Hipocampo/enzimología , Masculino , Memoria/efectos de los fármacos , Trastornos de la Memoria/inducido químicamente , Trastornos de la Memoria/enzimología , Fármacos Neuroprotectores/farmacología , Fármacos Neuroprotectores/uso terapéutico , Estrés Oxidativo/efectos de los fármacos , Porfobilinógeno Sintasa/metabolismo , Quercetina/uso terapéutico , Ratas , Ratas Wistar , Especies Reactivas de Oxígeno/metabolismoRESUMEN
The aim of the present study was to evaluate the metabolism of organic chromium and its effect on digestibility and intake of lambs. Four 4-month-old male lambs, each weighing 28 kg, were used. The animals were kept in metabolic cages for a period of 20 days (15 days of adaptation and 5 days of experimentation), in two experimental phases, with inverted treatments. Organic chromium was administered by intraruminal infusion of 1 mg of chromium-rich yeast (Saccharomyces cerevisiae) throughout the adaptive and experimental period. The dry material rates of the diet and feces of the animals were evaluated to estimate consumption, digestibility, and fecal production. During the experimental period, blood, feces, and urine were collected every 24 h to determine chromium levels. There was no significant difference in the excretion of chromium in the urine, and no mineral remnants were detected in the blood. Excretion was generally fecal. There was greater excretion of chromium in the feces of lambs in the treated group on day 0 and day 3, compared with the control group. The use of organic chromium promoted an increase in the consumption of dry material in the treated animals only at day 0 (P <0.05). The production of fecal dry matter was greater among the treated lambs than among the animals of the control group on day 1, day 2, day 3, and day 4 (P <0.05). The results obtained showed that organic chromium associated with live yeasts is not absorbed by the body and do not affect the intake time in the dose used.