Figure 6.

Effect of VOC exposure on skin explants. (A) Hematoxylin and eosin staining. NativeSkin models from a 30 year old donor female were cultured for 4 days with NativeSkin culture medium, exposed or not to VOCs (toluene, hexane, acetaldehyde, formaldehyde, acetone, 80 ppmV, each) for 4 hours every day. 24 hours after the last VOC exposure, samples were fixed in formalin and embedded in paraffin wax. 5 µm skin cross-sections were stained with hematoxylin eosin. Scale bar is 100 µm. (B) Apoptosis analysis. 5 µm skin cross-sections were immuno-stained for active caspase 3 to detect apoptotic cells. All pictures are representative of the whole sample. Scale bar is 100 µm. (C) Cell proliferation assessment. 5 µm skin cross-sections were immuno-stained for Ki-67. All pictures are representative of the whole sample. Scale bar is 100 µm. (D) proteasome activity. 24 hours after the last VOC exposure the epidermis was separated from the dermis and homogenized with a Dounce homogenizer and proteasome chymotrypsin-like activity was measured 24 hours post-treatment using the fluorogenic peptide LLVY-AMC. Data, mean ± SEM from 4 skin explants from two different donors (30, and 33 year old) females were used. **P < 0.01.