ABSTRACT
Tamoxifen (TAM) is a non-steroidal antiestrogen used in the treatment and prevention of hormone-dependent breast cancer. Tamoxifen therapy may be accompanied with hepatic injury and iron accumulation in this organ. The present study investigates the influence of the effective oral iron chelator, deferiprone (L1), in TAM-induced acute liver injury. Four groups of female Wistar rats were used: I, control; II, TAM; III, TAM+L1; IV, L1. Tamoxifen (75 mg/kg) was administered orally on the first and second day; L1 (50 mg/kg) was administered orally on the first, second and third day of the experiment. On the fourth day, parameters of oxidative state: lipid peroxidation (LP), glutathione (GSH) and catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) activities were estimated in liver homogenates. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), glutamate dehydrogenase (GLDH) levels and iron hepatic content were also evaluated. The TAM-induced oxidative damage was demonstrated by increased LP (52% above controls) and decreased GPx activity (to 92% of controls). The protective effect of L1 was manifested by attenuation of LP (p <0.05) and preserving of GPx activity. The TAM-induced increase of serum ALT and AST activity remained unchanged by L1 treatment. Significant increase of hepatic iron (Fe) level (41% above controls) was found in TAM-treated rats. Hepatic Fe accumulation was completely prevented by L1 treatment.
Subject(s)
Chemical and Drug Induced Liver Injury/drug therapy , Pyridones/pharmacology , Tamoxifen/adverse effects , Animals , Chemical and Drug Induced Liver Injury/etiology , Chemical and Drug Induced Liver Injury/metabolism , Deferiprone , Enzyme Assays , Female , Iron/metabolism , Iron Chelating Agents , Lipid Peroxidation/drug effects , Protective Agents , Pyridones/therapeutic use , Rats , Rats, Wistar , Treatment OutcomeABSTRACT
Iron is an essential element which, under certain conditions, can have prooxidant and cancerogenic effects. The effect of iron and iron chelators on the activity of selenoenzymes has been studied. Acute experiments in male Wistar rats demonstrated the prooxidant effect of iron on the selenoenzymes thioredoxin reductase (TrxR) and glutathione peroxidase (GPx). These enzymes represent an important part of the antioxidant defense system. Deferiprone (L1) has been shown to abolish the stimulating effect of iron on lipid peroxidation and reduced glutathione (GSH) levels, and also to inhibit the influence of iron on the activity of TrxR and GPx. Similarly, the flavonoid quercetin abolished the influence of iron on the activity of TrxR. The activity of both selenoenzymes has also been shown to be stimulated using L1, naringin (NAR), quercetin (QUE) and myricetin (MYR) in the absence of iron. Further studies including the combination of synthetic and natural compounds (e.g., flavonoids) are being considered for their possible development and clinical use in antioxidant therapies.
Subject(s)
Antioxidants/metabolism , Glutathione Peroxidase/metabolism , Iron Chelating Agents/pharmacology , Iron/pharmacology , Liver/drug effects , Oxidative Stress/drug effects , Pyridones/pharmacology , Thioredoxin-Disulfide Reductase/metabolism , Animals , Deferiprone , Flavanones/chemistry , Flavanones/pharmacology , Flavonoids/chemistry , Flavonoids/pharmacology , Iron/antagonists & inhibitors , Iron Chelating Agents/chemistry , Liver/enzymology , Liver/metabolism , Liver/pathology , Male , Pyridones/chemistry , Quercetin/chemistry , Quercetin/pharmacology , Rats , Rats, WistarABSTRACT
Although the metabolic and toxicological interactions between essential element selenium (Se) and toxic element cadmium (Cd) have been reported for a long time, the experimental studies explored mostly acute, high-dose interactions. Limited data are available regarding the effects of Se-deficiency on toxicokinetics of cadmium, as well as on the levels of key trace elements--copper, zinc, and iron. In the present study, male and female Wistar weanling rats (n = 40/41) were fed either Se-deficient or Se-adequate diet (<0.06 or 0.14 mg Se per kilogram diet, respectively) for 12 weeks, and from week 9 were drinking water containing 0 or 50 mg Cd/l as cadmium chloride. At the end of the 12-week period, trace element concentrations were estimated by AAS. Selenium-deficient rats of both genders showed significantly lower accumulation of cadmium in the liver, compared to Se-adequate rats. Zinc and iron hepatic levels were not affected by Se-deficiency. However, a significant elevation of copper was found in the liver of Se-deficient rats of both genders. Cadmium supplementation increased zinc and decreased iron hepatic level, regardless of Se status and decreased copper concentration in Se-adequate rats. Se-deficiency was also found to influence the effectiveness of cadmium mobilization in male rats.
