摘要：Oxidative stress is believed to be one of the major factors behind several acute and chronic diseases, and mayalso be associated with ageing. Excess formation of free radicals in miscellaneous body environment mayoriginate from endogenous response to cell injury, but also from exposure to a number of exogenous toxins.When the antioxidant defence system is overwhelmed, this leads to cell damage. However, the measurement offree radicals or their endproducts is tricky, since these compounds are reactive and short lived, and havediverse characteristics. Specific evidence for the involvement of free radicals in pathological situations hasbeen difficult to obtain, partly owing to shortcomings in earlier described methods for the measurement ofoxidative stress. Isoprostanes, which are prostaglandin-like bioactive compounds synthesized in vivo fromoxidation of arachidonic acid, independently of cyclooxygenases, are involved in many human diseases, andtheir measurement therefore offers a way to assess oxidative stress. Elevated levels of F2-isoprostanes havealso been seen in the normal human pregnancy, but their physiological role has not yet been defined. Largeamounts of bioactive F2-isoprostanes are excreted in the urine in normal basal situations, with a wideinterindividual variation. Their exact role in the regulation of normal physiological functions, however, needsto be explored further. Current understanding suggests that measurement of F2-isoprostanes in body fluidsprovides a reliable analytical tool to study oxidative stress-related diseases and experimental inflammatoryconditions, and also in the evaluation of various dietary antioxidants, as well as drugs with radical-scavengingproperties. However, assessment of isoprostanes in plasma or urine does not necessarily reflect any specifictissue damage, nor does it provide information on the oxidation of lipids other than arachidonic acid.
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