Carnosine and Retinol Synergistically Inhibit UVB-Induced PGE Synthesis in Human Keratinocytes through the Up-Regulation of Hyaluronan Synthase 2.

Skin aging results from complex interactions of intrinsic and extrinsic factors, leading to structural and biochemical changes such as wrinkles and dryness. Ultraviolet (UV) irradiation leads to the degradation of hyaluronic acid (HA) in the skin, and the with fragmented HA contributes to inflammation. This study revealed that the synergistic combination of carnosine and retinol (ROL) increases HA production in normal human epidermal keratinocytes (NHEKs) by upregulating hyaluronan synthase 2 (HAS2) gene transcription. Simultaneously, the combined treatment of carnosine and ROL significantly attenuates UVB-induced prostaglandin E (PGE) synthesis in NHEKs. A significant correlation exists between the increase of HA synthesis and the inhibition of PGE production. This study suggested that combined treatment of carnosine and ROL can improve skin aging phenotypes associated with UVB irradiation.