A wide range of environmental toxic substances causes adverse effects on organism and may represent a serious threat to human health. Exposure to xenobiotics may cause a broad range of metabolic disturbances, including iron homeostasis. Iron is both an essential trace element to the body and potentially toxic substance in excess. Perturbations in iron metabolism relate to the growing of various pathological states, including liver toxicity development and progression. Liver is the most important organ for a metabolic process and detoxification of harmful substances, along with iron storage and homeostasis. Usnic acid is a well-studied secondary metabolite isolated from lichens, which is extensively studied the broad variety of biological features. It is reported that usnic acid is effective for a range of pharmacological purposes such as antiviral, antimicrobial, antiproliferative, antiprotozoal, antitumor and anti-inflammatory. (+)-Usnic acid has been marketed as an ingredient of dietary supplements to promote weight loss. However, some studies reported that usnic acid has been associated with clinical cases of liver toxicity and contact allergy depending on the doses, thus its potential use as a drug is limited. However, there are limited data on the impact of usnic acid on iron homeostasis in the liver. The purpose of the present study was to investigate the possible effect of usnic acid on iron metabolism in rat liver. Material and methods. Male Fischer 344 rats (6 weeks of age) were housed in sterilized cages in a temperature-controlled room (24 °C) with a 12 h light/dark cycle, and given ad libitum access to water and NIH-41 irradiated pelleted diet. Gene expression in the liver of rats was analyzed by quantitative reverse transcription polymerase chain reaction techniques. Analysis of hepatic iron content was measured by inductively coupled plasma mass spectrometry. Results and discussion. The results showed that treatment of Fischer 344 (F344) rats with 60 mg usnic acid/kg bw/day for 6 weeks increased the expression of iron metabolism-related genes, Ftl and Fth, while the level of Tfrc mRNA was decreased in rat liver. Additionally, exposure of rats to usnic acid resulted in decrease of hepatic cellular iron content. Conclusion. The obtained results demonstrated that the exposure of rats to a low dose of usnic acid resulted in changes in the expression of iron metabolism related genes.
Keywords: usnic acid, iron metabolism, liver, toxicity
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