UTJECAJ PREOPTEREĆENJA ŽELJEZOM NA KONCENTRACIJU CINKA I BAKRA U MOZGU ŠTAKORA U MODELU EKSPERIMENTALNOG AUTOIMUNOSNOG ENCEFALOMIJELITISA

Željezo, bakar i cink predstavljaju esencijalne nutrijente, odnosno kationske elemente u tragovima. Oni se prenose specifiĉnim nosaĉima preko staniĉnih membrana, te u reakcijama sudjeluju kao anorganski ioni. Svaki od ovih elemenata ima svoju specifiĉnu funkciju i metaboliĉku regulaciju. Uloga cinka i bakra, na razini staniĉnog metabolizma je od posebnog znaĉaja u prvom redu zbog toga jer stotine danas poznatih enzima zahtjeva te metale za svoju katalitiĉku aktivnost. Bakar i željezo, zbog mogućnosti prijenosa elektrona predstavljaju osnovu oksidacijsko-redukcijskih procesa, kao što su primjerice procesi respiracije. Navedeni metali takoĊer mogu biti i toksiĉni u sluĉajevima ako njihova razina i distribucija u organizmu nije paţljivo regulirana, stoga pojedinaĉne smanjene ili povišene vrijednosti ovih elemenata u tragovima mogu dovesti do razvoja odreĊenih patoloških stanja. Preopterećenje ţeljezom moţe uzrokovati oksidacijski stres, tvorbom slobodnih radikala. Pogreške u metabolizmu bakra, cinka i ţeljeza odnose se na njihove poremećaje u transportu preko membrana i unutar stanice, što moţe biti posljedica meĊusobnih i nepoţeljnih interakcija u sluĉajevima patoloških promjena njihovih koncentracija u organizmu. Svrha ovoga rada je pokazati kako preopterećenje željezom, odnosno stanje povećanog unos željeza djeluje na promjenu koncentracije elemenata bakra i cinka u mozgu kod štakora u modelu eksperimentalnog autoimunosnog encefalomijelitisa (EAE), koji predstavlja animalni model za autoimunu i demijelinizacijsku, neurodegenerativnu bolest kod ljudi, multiplu sklerozu (MP). U eksperimentu su korišteni Dark Agouti (DA) štakori muškoga spola, koji su podjeljeni u tri skupine: eksperimentalnu skupinu, ţeljezo preopterećenih, kontrolnu skupinu tretiranu fiziološkom otpinom i netretiranu skupinu. Kako bi se koncentracija metala mogla izmjeriti, uzorci moţdanog tkiva su obraĊeni postupkom mikrovalne digestije. Koncentracije cinka i bakra u moţdanom tkivu su odreĊene primjenom ICP-OES metode na Prodigy High Dispersion ICP-OES spektrofotometru s pneumatskim raspršivaĉem. Prosjeĉne vrijednosti VI izmjerenih koncentracija cinka u moţdanom tkivu štakora u modelu EAE se ne razlikuju statistiĉki znaĉajno kod eksperimentalne skupine (tretirane ţeljezom) u odnosu na kontrolnu skupinu (tretiranu fiziološkom otopinom) i netretiranu skupinu štakora, dok je kod prosjeĉnih vrijednosti izmjerenih koncentracija bakra u moţdanom tkivu štakora pronaĊena statistiĉki znaĉajna razlika kod eksperimentalne skupine u odnosu na kontrolnu i netretiranu skupinu štakora, gdje je izraĉunata prosjeĉna vrijednost koncentracija bakra bila statistiĉki znaĉajno povećana.Iron, copper and zinc are essential nutrients, or cationic trace elements. They are transferred by specific carriers across cell membranes, and they are involved in the reactions, as inorganic ions. Each of these elements has a specific function and metabolic regulation. The role of zinc and copper, at the level of cellular metabolism is of particular importance in the first place, because hundreds of known enzymes request these metals for its catalytic activity. Copper and iron, because of their possibility of electron transfer, are basis of oxidation-reduction processes, such as respiration processes. These metals can also be toxic in case if their levels and distribution in organism isn't carefully regulated, so individually decreased or increased values of these trace elements can lead to development of certain pathological conditions. Iron overload can cause oxidative stress, through formation of free radicals. Defects in the metabolism of copper, zinc and iron are related to their disorders in transport across the membrane and within the cell, which may be the result of mutual and undesirable interaction in cases of pathological changes of their concentration in the body. The aim of this study is to show how iron overload, or condition of increased intake of iron affects the change in concentration of the elements copper and zinc in the brain of the rats in the model of experimental autoimmune encephalomyelitis (EAE), which is an animal model for autoimmune and demyelination, neurodegenerative disease in humans, multiple sclerosis (MP). Dark Agouti (DA) male rats were used in this experiment and they were divided into three groups: experimental group (iron overloaded), the control group (treated with saline solution) and the untreated group. To be able to measure the concentration of metals, samples of brain tissue were processed using microwave digestion. The concentrations of zinc and copper in the brain tissue were determined using ICP-OES methods on Prodigy High Dispersion ICP-OES spectrophotometer with pneumatic nebulizer. Average values of the measured concentrations of zinc in the brain tissue of rats in a model of EAE is not statistically significant different in the experimental group compared to the control and untreated group of rats, while average values of the measured copper concentration varied in the brain tissue of rats. Statistically significant increase was found in the experimental group compared to the control group and the untreated rats