(D) RT-qPCR quantification of relative Tgfb1 level in the epidermis of acutely irradiated (Ac-UV) and non-irradiated Ppard +/+ and -/- mice. Tgfb1: Ppard +/+ no UV vs Ac-UV P= 0.034, Ppard +/+ Ac-UV vs Ppard Ac-UV P= 0.030. N=2-3 animals per group, one representative experiment is shown out of three independent replicates. 