Effect of Saikokeishito, a Kampo medicine, on hydrogen peroxide-induced premature senescence of normal human dermal fibroblasts

OBJECTIVE: Saikokeishito (TJ-10) is a Kampo (traditional Japanese herbal) medicine, clinically used for hundreds of years in East Asia. Among its various mechanisms elucidated so far, TJ-10 inhibits the production of transforming growth factor-beta 1 (TGF-beta 1) and development of pancreatic fibrosis in vivo. Oxidative damage of normal human dermal fibroblasts (NHDFs) in the corium is a cause of human dermal senescence. Our aim was to determine whether TJ-10 protects NHDFs from premature senescence by hydrogen peroxide (H2O2). METHODS: Premature senescence was induced in NHDFs by 200 mu mol/L H2O2 for 4 h. Cell viability and the expressions of p53, AMP-activated protein kinase alpha 1 (AMPKa1), AMPKa2, and 14-3-3 protein sigma (14-3-3 sigma) were measured in NHDFs treated with TJ-10 for 48 h before exposure to H2O2 for 4 h. RESULTS: Cell viability after treatment with 200 mu mol/L H2O2 for 4 h was similar (about 80%) to after pre-treatment with TJ-10. Ascorbic acid as a control did not protect NHDFs from damage by 200 mu mol/L H2O2. Treatment with 200 mu mol/L H2O2 tended to up-regulate p53 and to down-regulate SIRT1 and AMPKa1, but had no effect on AMPKa2 and 14-3-3 s expression. Pretreatment with TJ-10 inhibited H2O2-induced up-regulation of p53 and enhanced AMPKa1 expression. CONCLUSION: It is suggested that Saikokeishito has a protective effect on oxidative stress-induced senescence of NHDFs.