Fluoride induced oxidative stress, immune system and apoptosis in animals: a review

Halfway through the twentieth century, fluoride piqued the interest of toxicologists due to its deleterious effects due to high concentrations in animals as well as in human populations suffering from several types of disorders and in in-vivo experimental models. Until the 1990s, the toxicity of fluoride was largely ignored due to its “good reputation” for preventing caries via topical application and in dental toothpaste. However, in the last decade, interest in its undesirable effects has resurfaced due to the awareness that this element interacts with cellular systems even at low doses. In recent years, several investigations demonstrated that fluoride can induce oxidative stress and modulate intracellular redox homoeostasis; lipid peroxidation and protein carbonyl content, as well as alter gene expression and cause apoptosis. Genes modulated by fluoride include those related to the stress response, metabolic enzymes, the cell cycle, cell–cell communications and signal transduction. The primary purpose of this review is to examine recent findings on the effects of fluoride on oxidative stress, immune system and apoptosis in the animal as well as in human system.