Effects of rice fermentation and its bioactive components on UVA-induced oxidative stress and senescence in dermal fibroblasts

Photoaging, caused by ultraviolet (UV) radiation, is characterized by the senescence of skin cells and reduction of collagens. Although rice fermentation is widely used in the cosmetics, its impact on skin photoaging is still not well understood. Herein, we investigated the possible effectiveness of Maifuyin, a fermented rice product, and its components, succinic acid (SA), and choline, for safeguarding UVA-exposed human dermal fibroblasts (HDFs) against photoaging. In this study, the effects of Maifuyin, SA, and choline on UVA-induced cell death and senescence in fibroblasts were evaluated in cell counting kit-8 (CCK-8), expression of beta-galactosidase (beta-GAL), and matrix metalloproteinases (MMP)-1. To identify oxidative stress, the investigation focused on reactive oxygen species, glutathione, superoxide dismutase, and malondialdehyde. Additionally, a mRNA sequencing technology (RNA-seq) was applied to study the underlying mechanisms of these components on UVA-induced photoaging. Meanwhile, the level of C-X-C motif chemokine ligand 2 (CXCL2) in the cell supernatant was confirmed to assess the autocrine chemokine level. To reassess the involvement of CXCL2, the expression of beta-GAL was evaluated in fibroblasts treated with or without CXCL2. The results indicated that 1 mg/mL Maifuyin and SA inhibited UVA-induced senescence in fibroblasts, MMP-1 expression, and oxidative damage. The RNA-seq revealed 1 mg/mL Maifuyin and SA might be recruited chemokine CXCLs to inhibit MMPs production and fibroblast senescence via TNF alpha, MAPK, and NF-kappa B pathways. ELISA results showed a significant reduction of autocrine CXCL2 in UVA-irradiated HDFs by pretreating Maifuyin and SA. The beta-GAL staining assay revealed that CXCL2 treatment increased beta-GAL activity, while the administration of Maifuyin and SA counteracted this effect in HDFs. These results highlighted the potential use of Maifuyin and SA as promising candidates for anti-photoaging applications. UVA irradiation poses significant threat to human dermal fibroblasts via recruiting chemokine CXCLs, particularly CXCL2, which subsequently induces cellular senescence through the TNF alpha, MAPK, and NF-kappa B pathways. In this study, Maifuyin, a fermented rice product, along with its bioactive components succinic acid (SA), exhibit protective effects against UVA-induced photoaging. At a concentration of 1 mg/mL, Maifuyin and SA effectively prevent UVA-induced senescence, reduce MMP-1 expression, and mitigate oxidative damage in fibroblasts through inhibiting CXCL2. These findings highlight Maifuyin and SA as promising candidates for innovative anti-photoaging therapy.image