earticle

영어

Bifidobacterium longum (B. longum) is a species of gram-positive anaerobic bacterium which can be found intestines of humans. B. longum, a potential probiotic used in the food industry, promotes the health of human intestinal tract by reduction of harmful gram- negative bacteria and toxic molecules. Also, B. longum has numerous biological effects, such as anti-cancer, activation of immune response and reduction of DNA damage. Ultraviolet (UV) irradiation has many adverse effects on skin, including inflammation, alteration in the extracellular matrix, cellular senescence and apoptosis. In this study, we investigated the protective effect of B. longum extracts against UVB-induced cellular damage in human dermal fibroblasts (HDFs). B. longum extracts at concentration 0.01 ~ 0.02% (w/v) did not affect cell viability in HDFs. When UVB-exposed HDFs were treated with B. longum extracts, cell viability was substantially enhanced in a dose -dependent manner. To investigate inhibitory effects against cellular senescence of B. longum extracts in HDFs, we performed SA-β-gal staining. UVB-exposed HDFs with B. longum extracts were decreased SA-β-gal positive cells approximately 40% at the concentration of 0.02% (w/v). Flow cytometry was used to determine changes of cell cycle in B. longum extracts treated- HDFs. UVB irradiation slightly increased the percentage of cell population in the sub-G1 phase. However, the proportion of cells in sub-G1 phase were decreased approximately 50% by treatment with B. longum extracts. These results suggest that B. longum extracts reduce UVB-induced cellular senescence and apoptosis in HDFs. Thus, B. longum extracts might be used as a potential agents for protection of UVB-induced skin cell damage.