Effect of triptolide on activation of PPARγ in RSF. Cells were co-transfected with a PPRE-driven luciferase reporter plasmid, a PPARγ expression plasmid, and an internal control plasmid. Then the transfected cells were treated with known PPARγ ligand or triptolide and luciferase activity was determined as described in Materials and Methods. Data are the mean ± S.D. for triplicate cultures and representative results from 3 independent experiments are shown. *, p < 0.05 versus other groups. Significance was evaluated by Student's t-test with a Bonferroni's correction.