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-β1（TGF-β1） and development of pancreatic fi brosis in vivo. Oxidative damage of normal human dermal fi broblasts（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 μmol/L H2O2 for 4 h. Cell viability and the expressions of p53, AMP-activated protein kinase α1（AMPKα1）, AMPKα2, and 14-3-3 protein sigma（14-3-3 σ） 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 μmol/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 μmol/L H2O2. Treatment with 200 μmol/L H2O2 tended to up-regulate p53 and to down-regulate SIRT1 and AMPKα1, but had no effect on AMPKα2 and 14-3-3 σ expression. Pretreatment with TJ-10 inhibited H2O2-induced up-regulation of p53 and enhanced AMPKα1 expression. CONCLUSION： It is suggested that Saikokeishito has a protective effect on oxidative stressinduced senescence of NHDFs.