Oxidative Stress-Based Toxicity of Chemical and Physical Agents

The environmental pollution may have an impact on the incidence of lung, skin, and eye diseases, as the corresponding organs are directly exposed to environmental stressors. Industrial, agricultural, pharmacological, and lifestyle applications have increased the types and amounts of xenobiotic agents to which humans are exposed. Unfortunately, the human body is also subject to injury from physical agents arising from occupational environments such as ionizing radiations and UV light, released by nuclear plants and therapeutic activities. Most of the chemical and physical agents mediate cellular injury by their ability to cause oxidative stress (OS) to cell components. They induce oxidative injury in susceptible biomolecules and/or modulate redox-sensitive elements including signal transduction pathways and gene expression. The interaction of these agents also leads to radical cascades and lipid peroxidation, thereby exacerbating the endogenous OS. This chapter is a very comprehensive review on the OS exerted by environmental contaminants including drugs, heavy metals, pesticides, aromatic hydrocarbons, and solvents. The authors emphasize that not all contaminants act as pro-oxidants in a similar fashion. Some of these agents are able to exert OS in a direct and major way such as therapeutic drugs, pesticides, and solvents. Others like heavy metals raise OS through a pleiotropic response that generates high levels of reactive species (RS). This chapter also covers the toxic effects of cigarette smoke and particles like asbestos, nanoparticles (NPs), and airborne particles on the lung. The various mechanisms by which toxins can induce oxidative damage to cells are also illustrated by consideration of aflatoxins and venom components.