Oxidative injury is caused by oxidative stress, which is an imbalance between reactive oxygen species (such as free radicals or peroxides) and antioxidants in the body.
Long-term oxidative stress has toxic effects on the body’s cells, resulting in oxidative injury. Furthermore, some reactive oxygen species act as messengers in redox signaling. Thus, oxidative stress can disrupt the normal mechanisms of cellular signaling.
Oxidative stress can cause chronic inflammation, which plays a role in a wide range of chronic diseases including cardiovascular diseases, pulmonary diseases and diabetes. The effects of oxidative stress may contribute to several neurodegenerative conditions, such as Parkinson's disease and Alzheimer's disease. The brain is particularly vulnerable to oxidative stress because brain cells require a large amount of oxygen.
There is also a variety of evidence that suggests that reactive oxygen and nitrogen species contribute to the age-related development of cancers.