CHAPTER 10: Photodamage in Mitochondria

This chapter discusses the mechanisms of photodamage in the mitochondria, possible contributors, and protective interventions against this damage. Photodamage has been shown to have profound effects in the mitochondria of skin cells, mainly through oxidative damage. With its proximity to the electron transport chain, mitochondrial DNA (mtDNA) is highly sensitive to damage from the increasing levels of reactive oxygen species (ROS). This damage can come in the form of oxidative base lesions, as well as several different mutations and deletions that can impact the correct assembly of electron transport chain subunits, resulting in further ROS generation. This feeds into both the free radical and vicious cycle theories of ageing. In addition to ultraviolet (UV), pollutants such as particulate matter (PM) and ozone have also been shown to induce similar mitochondrial damage to that of photodamage, including ROS generation, DNA damage and inhibition of DNA repair pathways. These pollutants have the ability to synergistically increase the mtDNA damage caused by UV. Protection against mitochondrial photodamage include endogenous mechanisms to prevent and/or repair the damage, as well as the introduction of exogenous antioxidants from skin formulations and diet.