Oxidative mechanisms in metal toxicity

Abstract

Mechanisms of metal toxicity have not been fully understood. It was proven in the last decades that certain metals induce increased generation of free radicals, which react lipids, proteins and nucleic acids in the organism inducing tissue-damaging effects and cell death. Metals such as iron copper, chromium, etc. undergo redox cycling and directly catalyze production of free radicals, while mercury, nickel, lead and some others act indirectly by inhibition of antioxidative mechanisims. This paper presents basic understanding of free radicals, their influence on the organism and antioxidative system. Particular attention is given to oxidative mechanisms in which iron, copper, chromium, mercury and lead play role in generation of free radicals and oxidative stress, contrary to zinc which has a significant role in antioxidative cell protection.

Mehanizmi toksičnosti metala su još uvek nedovoljno proučeni. Poslednjih decenija dokazano je da određeni metali indukuju i povećanu produkciju slobodnih radikala koji reaguju sa lipidima, proteinima i nukleinskim kiselinama organizma, što rezultira različitim oštećenjima, pa i smrću ćelija. Metali sa promenljivom valencom, kao što su gvožđe, bakar, hrom i dr. direktno katalizuju produkciju slobodnih radikala u reakcijama redoks-ciklusa, dok kadmijum, živa, nikl, olovo i neki drugi metali deluju indirektno tako što inhibiraju antioksidativne mehanizme organizma. U radu su izneta osnovna saznanja o slobodnim radikalima, njihovom dejstvu na organizam i antioksidativnom sistemu organizma. Posebno su obrađeni oksidativni mehanizmi kojima metali gvožđe, bakar, hrom, kadmijum, živa i olovo ostvaruju ulogu u nastanku slobodnih radikala i oksidativnog stresa za razliku od cinka koji ima značajnu ulogu u antioksidativnoj zaštiti ćelija.