Glutathione (GSH) plays several important roles in the protection of cells against oxidative damage, particularly following exposure to xenobiotics. Ferric nitrilotriacetate (Fe-NTA) is a potent depletor of GSH and also enhances tissue lipid peroxidation. In this study, we show the effect of Fe-NTA treatment on hepatic GSH and some of the glutathione metabolizing enzymes, oxidant generation and liver damage. The level of hepatic GSH and the activities of glutathione reductase, glutathione S-transferase, glutathione peroxidase, and glucose 6-phosphate dehydrogenase all decrease following Fe-NTA administration. In these parameters the maximum decrease occurred at 12 h following Fe-NTA treatment. In contrast, γ-glutamyl transpeptidase was increased at this time. Not surprisingly, the increase in the activity of γ-glutamyl transpeptidase and decreases in GSH, glutathione peroxidase, glutathione reductase, glucose 6-phosphate dehydrogenase and glutathione S-transferase were found to be dependent on the dose of Fe-NTA administered. Fe-NTA administration also enhances the production of H2O2 and increases hepatic lipid peroxidation. Parallel to these changes, Fe-NTA enhances liver damage as evidenced by increases in serum transaminases. Once again, the liver damage is dependent on the dose of Fe-NTA and is maximal at 12 h. Pretreatment of animals with antioxidant, butylated hydroxy anisole (BHA), protects against Fe-NTA-mediated hepatotoxicity further supporting the involvement of oxidative stress in Fe-NTA-mediated hepatic damage. In aggregate, our results indicate that Fe-NTA administration eventuates in decreased hepatic GSH, a fall in the activities of glutathione metabolizing enzymes and excessive production of oxidants, all of which are involved in the cascade of events leading to iron-mediated hepatic injury.
Ferric nitrilotriacetate (Fe-NTA) is a potent nephrotoxic agent. In this communication, we show the modulatory effect of DL-a-tocopherol (Vitamin-E) on ferric nitrilotriacetate (Fe-NTA)-induced renal oxidative stress, toxicity and hyperproliferative response in rats. Fe-NTA-treatment enhances the susceptibility of renal microsomal membrane for iron-ascorbate-induced lipid peroxidation and hydrogen peroxide generation which are accompanied by a decrease in the activities of renal antioxidant enzymes, catalase, glutathione peroxidase, glutathione reductase and glutathione-S-transferase and depletion in the level of renal glutathione. Parallel to these changes, a sharp increase in blood urea nitrogen and serum creatinine has been observed. In addition, Fe-NTA-treatment also enhances renal ornithine decarboxylase activity (ODC) and increases [3H]thymidine incorporation in renal DNA. Prophylactic treatment of animals with Vit.E daily for 1 week prior to the administration of Fe-NTA resulted in the diminution of Fe-NTA-mediated damage. Enhanced susceptibility of renal microsomal membrane for lipid peroxidation induced by iron-ascorbate and hydrogen peroxide generation were significantly reduced (P50.05). In addition, the depleted level of glutathione and inhibited activities of antioxidant enzymes recovered to significant levels (P50.05). Similarly, the enhanced blood urea nitrogen and serum creatinine levels which are indicative of renal injury showed a reduction of about 50% at a higher dose of Vit.E. The pretreatment of rats with Vit.E reduced the Fe-NTA-mediated induction in ODC activity and enhancement in [3H]thymidine incorporation in DNA. The protective effect of Vit.E was dose dependent. In summary, our data suggest that Vit.E is an effective chemopreventive agent in kidney and may suppress Fe-NTA-induced renal toxicity.
Serotonergic systems are involved in the central regulation of nociceptive sensitivity. Fluoxetine, a selective inhibitor of the reuptake of serotonin (5-hydroxytryptamine, 5-HT), was administered orally (0.16, 0.32, 0.8 mg kg(-1) daily for 7 days), intraperitoneally (0.04, 0.08, 0.16 mg kg(-1) day(-1) for 7 days and a single dose of 0.32 mg kg(-1)) and intracerebroventricularly (10 microg/rat) to rats and nociceptive sensitivity was evaluated using the formalin test (50 microL of 2.5% formalin injected subcutaneously). The effect of fluoxetine was also studied in the presence of 5,7-dihydroxytryptamine creatinine sulfate (5,7-DHT) and after co-administration with morphine. Oral (0.8 mg kg(-1)), intraperitoneal (0.16 and 0.32 mg kg(-1)) and intracerebroventricular (10 microg/rat) fluoxetine induced antinociception in the late phase of the formalin test. Furthermore, intrathecal administration of 5-HT (100 microg/rat) induced an analgesic effect. The analgesic effect of fluoxetine (0.16 and 0.32 mg kg(-1), i.p.) and 5-HT (100 microg/rat, i.t.) was abolished by pre-treatment with 5,7-DHT (100 microg/rat, i.t.). In addition, the analgesic effect of 5-HT (100 microg/rat, i.t.) was decreased by pre-treatment with naloxone (2 mg kg(-1), i.p.). Morphine (5 mg kg(-1), i.p.) induced analgesia that was increased by fluoxetine (0.32 mg kg(-1), i.p.). These results suggest that fluoxetine has an antinociceptive effect in tonic inflammatory pain through functional alteration of the serotonergic system and also potentiates the analgesic effect of morphine.
RESUMO: "Avaliação do efeito antihiperlipidêmico de Citrullus colocynthis". Hiperlipidemia é um fator de risco bem conhecido para diversas doenças inclusive aterosclerose, doenças cardíacas e derrame cerebral. Na procura de potenciais agentes antihiperlipidêmicos a partir de plantas para prevenir essas doenças, a polpa e as sementes de Citrullus colocynthis foram testadas para verifi car seus efeitos no perfi l lipídico de coelhos Nova Zelândia hiperlipidêmicos. Nos grupos experimentais que receberam a polpa de C. colocynthis ou 100 mg/kg das sementes, os perfi s lipídicos foram signifi cantemente reduzidos quando comparados ao grupo de controle (P<0,05).
Unitermos: Citrullus colocynthis, Cucurbitaceae, hiperlipidemia, coelhos.ABSTRACT: Hyperlipidemia is a well-known risk factor for several illnesses including atherosclerosis, heart and vascular diseases and stroke. In the search for potential antihyperlipidemic agents from plants to prevent these conditions, the pulp and the seeds of Citrullus colocynthis were assessed for their effects on the lipid profi le of hyperlipidemic New Zealand rabbits. In the experimental groups that received the pulp of C. colocynthis or 100 mg/kg of seeds, the lipid profi les were signifi cantly reduced when compared to the control group (P<0.05).
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