Figure 18. Effects of EGCG in antioxidative enzyme gene expressions and activities in short term treatment. Young (PDL20-30) HDF was treated with 25 and 50μM EGCG for 24 hours and then the antioxidative enzyme gene expressions (A) were measured by quantitative real-time PCR and the enzyme activities (B) were determined by Cayman chemical kits, as mentioned in Section 3.2.7 and 3.2.8, respecctively. The data shown are the mean from independent experiments, #p . 18. Effects of EGCG in antioxidative enzyme gene expressions and activities in short term treatment. Young (PDL20 -30 ) HDF was treated with 25 and 50 μM EGCG for 24 hours and then the antioxidative. senescence. In the process of HDF reaching the end point, samples were collected, and intracellular ROS accumulation, mitochondrial integrity, antioxidative enzyme activities and gene expressions. as determined by one-way ANOVA. 90 Effects of EGCG in long term treatment In the long term treatment, the middle-aged HDF (PDL 35) was continuously cultured in MEM with 12 .5 μM of EGCG until