Oxygen radicals.

Abstract

Superoxide radicals play a role in at least three different levels of the biochemistry of inflammation, 1) They are produced sometimes excessively by macrophages and polymorphonuclear neutrophils during phagocytosis (bacterial killing). 2) A plasmatic neutrophil chemotactic factor is activated by O2 -. and 3) These radicals can cause chromosome breakage and other aberrations and also activate a plasmatic clastogenic factor present in various autoimmune diseases and in high energy irradiation cases. Superoxide dismutases can probably be useful for the control and treatment of autosustaining inflammatory conditions. Pharmacological application of superoxide dismutase is governed by a number of parameters including 1) Circulation time, 2) Penetration of cells, 3) Organ specificity, 4) Intracellular localization of the exogenous superoxide dismutase. Some recent experimental results in these areas will be described using both free superoxide dismutase and liposomal encapsulated enzyme. Although superoxide anions are the primary oxygen radicals produced in biological systems, they can also give rise to a cascade of other radicals such as hydroxy, carbonate and lipoperoxy radicals. Other enzymic systems for protection against uncontrolled oxidative processes exist and may have a future medical utility in certain cases.