Histochemical visualization of oxidant stress

Free radicals induce oxidative modification in distinct components of the l iving matter (lipid, proteins, and DNA). For qualitative and quantitative d etermination of free radical-induced modifications, different, more or less sensitive biochemical methods are available. Because of the high reactivit y and short life of free radicals, ongoing oxidative damage is generally an alyzed by measurement of secondary products-such as H2O2, oxidized proteins , peroxidized lipids, and their breakdown products, oxidized DNA-or by fluo rographic analysis in combination with fluorescent dyes such as dichloroflu orescin (DCFH). In addition, the determination of free radical-related oxid ation products is usually carried out in plasma, urine, or, less frequently , in bioptic material. Consequently, biochemical data seldom reflect the ef fects of free radical insults in situ. The histochemical visualization of s elected molecular markers of oxidative damage can often provide more valuab le information concerning the in vivo distribution of oxidative processes. This review summarizes the methods currently available for histochemical de tection and indirect visualization of free radical-induced alterations in t issues and isolated cells. (C) 2000 Elsevier Science Inc.