Oxidative stress is an unavoidable consequence of life in an oxygenrich
atmosphere. Reactive oxygen species (ROS) and reactive
nitrogen species (RNS) are generated as by-products of aerobic
metabolism and are critical intermediates in the normal physiology
and pathophysiology of hepatocytes. To cope with ROS and RNS,
cells have developed antioxidant defenses in order to maintain the
balance between production and detoxification processes. ROS are
important in the creation of oxidative stimuli required for normal
physiologic homeostasis of hepatocytes, but when the equilibrium
between ROS generation and the antioxidant defense of the cell is
disrupted, the consequence is the generation of an oxidative stress
condition. In this chapter we will describe the main cellular source
of free radicals, the damages generated by ROS accumulation, and
all the principal enzymatic and non-enzymatic antioxidant defenses.
