Fruit Acid Inhibits UV-Induced Skin Aging via PI3K/Akt and NF-κB Pathway Inhibition.

Backgrounds: Ultraviolet (UV) radiation-induced photoaging is a multifaceted biological process. Fruit acids have shown promise in combating photoaging. This study aims to investigate the mechanisms underlying the protective effects of fruit acids on UV-induced skin photoaging.

Methods: Initially, we induced skin photoaging in rats through UV irradiation. Subsequently, the model group received glycolic acid treatment. The reparative effects of glycolic acid on skin tissue morphology and structure were assessed using Hematoxylin-eosin (HE) staining. The influence of glycolic acid on oxidative stress indicators (Superoxide Dismutase (SOD), Glutathione Peroxidase (GSH-Px), Malondialdehyde (MDA), Catalase (CAT)) and levels of cellular inflammatory factors (Interleukin-6 (IL-6), Tumor Necrosis Factor-alpha (TNF-α), IL-1β, Interferon-gamma (IFN-γ)) in photoaged skin was evaluated via Enzyme-Linked Immunosorbent Assay (ELISA). Additionally, alterations in collagen expression and levels of proteins associated with the Phosphoinositide 3-kinase/Protein Kinase B (PI3K/Akt) and Nuclear Factor kappa B (NF-κB) signaling pathways were determined through Western blot analysis.

Results: Compared to the model group, the fruit group exhibited a decrease in the thickness of the skin epidermal keratinization layer, an increase in dermal thickness, and more vigorous cortical secretion. Moreover, compared with the model group, the fruit group showed significant increases in SOD activity, CAT, GSH-Px, Collagen I, Collagen III, Collagen VII, and elastin. Conversely, levels of MDA, IL-6, IL-1β, IFN-γ, and TNF-α were lower in the fruit acid group than in the model group. Additionally, fruit acid treatment inhibited the phosphorylation levels of PI3K, Akt, and p65 induced by UV.

Conclusion: Fruit acid demonstrates the ability to diminish the oxidative stress and inflammatory responses in skin photoaging rat models, thereby facilitating collagen recovery and ameliorating symptoms of skin photoaging. Its potential mechanism may entail the inhibition of the activation of the PI3K/Akt and NF-κB signaling pathways.