Immunohistochemistry

Several biomarkers of protein oxidation, glycoxidation, and lipid peroxidation are now identified and can be detected in situ by immunohistochemistry. In situ measurements allow for the detection of specific cells and specific localization of oxidative stress biomarkers (e.g., protein carbonyls, nitrotyrosine, chlorotyrosine, carbohydrate end-products, malondialdehyde (MDA), 4-hydroxy-2-nonenal (4-HNE), iNOS, and COX) affecting only a small fraction of tissue and cells. Because tissues are usually fixed in formalin, investigators must focus on well-defined products that are stable in this fixative. However, a major problem may emerge, which is the difficulty in measuring trace concentration of individual oxidation end-products in tissue by relatively sophisticated chemical assay procedures. Protein, lipid, and DNA damage can be visualized in tissues using monoclonal or polyclonal antibodies. In this chapter, we feature several cases in which immunohistochemical techniques directed to damage products and pro-oxidant enzymes are used to support investigation of the pathogenesis of several diseases. The chapter also gives a perspective on the diversity of applications of immunochemistry in the ever-emerging field of oxidative stress.