Research progress on skin photoaging and oxidative stress

Abstract

Skin photoaging, which is a kind of exogenous aging, refers to skin elasticity degradation, skin roughening, and wrinkle formation processes because of cascading reactions of a series of kinases after growth factor receptors and cytokine receptors are activated on a cell surface under the UV effect. An extensively recognized skin photoaging mechanism is free radical-oxidative stress concept, proposed by Sohal who represents the authority of the US aging studies. Over the past decade, many new developments in the oxidative stress mechanism have been achieved in terms of the occurrence, development, prevention, and treatment of photodamage.

Keywords: UV; oxidative stress; photoaging; photodamage.

Figure 1

Mechanism of skin photoaging caused by UVA and UVB. UVA (315–400 nm): UVA penetrates the corium layer more deeply, with the strongest ability of generating reactive oxygen species (ROS) and lipid peroxidases, thereby causing damage to collagens and elastic fibres in dermal tissues. UVB (280–315 nm): UVB acts on the epidermis and causes skin erythema, skin tumours, and immunosuppression. UVC (100-280 nm): UVC is nearly completely absorbed by the ozone layer in the atmosphere

Figure 2

Series of changes caused by ROS and inflammation. ROS and inflammation can cause pigmentation and changes in matrix metalloproteinase activity, extracellular matrix components, skin immunity, and barrier function