Possible interference of PPARγ against PUVA induced modulation of the cellular stress response system.

(A) RT-PCR was performed to measure the expression of NRF2 mRNA 6 and 24 h after PUVA exposure, w/o Octa post-incubation. The level of NRF2 mRNA was normalized to the expression of GAPDH and is expressed relative to untreated control cells (**p<0.001 respect to Ctr; ^##p<0.001 compared with PUVA-treated fibroblasts). (B) RT-PCR was performed to measure the expression of HO-1 mRNA 6 and 24 h after PUVA exposure, w/o Octa post-incubation. The level of HO-1 mRNA was normalized to the expression of GAPDH and is expressed relative to untreated control cells (**p<0.001 respect to Ctr; ^##p<0.001 compared with PUVA-treated fibroblasts). (C) GSH concentrations were determined by HPLC-MS) as described in Materials and Methods (*p<0.05 respect to control fibroblasts). (D) RT-PCR was performed to measure the expression of FoxO1 mRNA 6 and 24 h after PUVA exposure, w/o Octa post-incubation. The level of FoxO1 mRNA was normalized to the expression of GAPDH and is expressed relative to untreated control cells. *p<0.05 respect to control fibroblasts; ^#p<0.05 compared with PUVA-treated fibroblasts.