Skin aging is a series of complex biological changes that involve both endogenous and exogenous factors. Endogenous factors refer to the process of procedural natural aging that occurs as the skin ages. Exogenous factors refer to aging changes caused by environmental factors, including physical, chemical, biological and other factors. The most important type of skin aging is photoaging caused by repeated exposure to ultraviolet light. Ultraviolet rays can damage DNA directly and generate free radicals. Free radicals can trigger a series of damage changes inside and outside cells. As changes in cell levels accumulate, visible phenomenon of skin photoaging will occur.
Treatments for skin photoaging include nutritional supplements, pharmaceutical theapies, physical therapies, etc. People have never stopped attempts to fight against aging. Recent studies demonstrated that cell signaling pathway regulators can interfere with photoaging by sending signals to skin cells. For example, transforming growth factor β1 (TGFβ1) promotes proliferation of human fibroblasts, reduces UV-induced collagen degradation and increases the collagen content of skin cells. However, effects of single-target treatment are not optimal.