Induction of inflammatory and metabolic genes (mRNA, fold of induction) by photo-oxidized commercial squalene and squalene from photo-oxidized human skin surface lipids (SSL).

Commercial squalene or SSL were exposed to UVA+UVB irradiation (dose UVA = 20 J/cm2 and UVB = 2 J/cm2). Photo-exposed SSL were subjected to TLC and squalene containing spot was collected as per Materials and Methods. Squalene samples or 0.1% methanol (a vehicle for squalene) were added to NHEK cultures (final concentration - 1 µg/mL) for 3 h. Then, cells were thoroughly washed and RNA was isolated. Gene expression was determined by RT-PCR and results were expressed as a fold of induction versus vehicle. Three independent experiments were carried out and the mean values ±S.D. were calculated. *P<0.05 and †P<0.001.