Oral Probiotics Improve Photoaging in UVB-Exposed Mice by Modulating Microbiome and MAPK Pathway.

The skin acts as a physical defense barrier and maintains homeostasis by regulating and preserving moisture and temperature, thus protecting the body.

Ultraviolet (UV) radiation is a representative extrinsic factor that induces photoaging by excessive generation of reactive oxygen species (ROS) in the epidermis and dermis, promoting the oxidation of structural proteins and lipids.

In addition, continuous exposure to UVB has been considered as one of the causes of skin cancer by causing DNA damage and mutation.

Oxidative stress induced by UV exposure activates the mitogen-activated protein kinase (MAPK) pathway through phosphorylation of p, extracellular signaling regulatory kinase (ERK), and Jun-N-terminal kinase (JNK) proteins.

Activation of the MAPK pathway triggers the release of pro-inflammatory cytokines and increases the expression of matrix metalloproteinases (MMPs), an enzyme that degrades the extracellular matrix (ECM). As a result, it breaks down the main structural proteins collagen and elastin, reducing skin elasticity and promoting wrinkle formation.

Recently, the concept of nutricosmetics, also called the inner beauty, has emerged with increasing interest in suppressing skin aging. Traditionally, cosmetics have been developed in a form that is absorbed through the skin, but nutricosmetics involve the intersection of food and cosmetics, that is, ingesting functional substances to improve the health of the skin.