Cell culture models for oxidative stress: superoxide and hydrogen peroxide versus normobaric hyperoxia

According to the free radical theory of aging, loss of cellular function during aging is a consequence of accumulating subcellular damage inflicted by activated oxygen species. In cells, the deleterious effects of activated oxygen species may become manifest when the balance between radical formation and destruction (removal) is disturbed creating a situation denoted as 'oxidative stress'. Cell culture systems are especially useful to study the effects of oxidative stress, in terms of both toxicity and cellular adaptive responses. A better understanding of such processes may be pertinent to fully comprehend the cellular aging process. This article reviews three model systems for oxidative stress: extracellular sources of O₂^- and H₂O₂, and normobaric hyperoxia (elevated ambient oxygen). Methodological and practical aspects of these exposure models are discussed, as well as their prominent effects as observed in cultures of Chinese hamster cell lines. Since chronic exposure models are to be preferred, it is argued that normobaric hyperoxia is a particularly relevant oxidative stress model for in vitro cellular aging studies.