M. Robert et al., Harmful effects of UVA on the structure and barrier function of engineeredhuman cutaneous tissues, INT J RAD B, 75(3), 1999, pp. 317-326
Purpose: To investigate the effects of a single UVA exposure on engineered
human cutaneous tissues.
Materials and methods: Skin equivalents (SE) were obtained by culturing ker
atinocytes on fibroblast-populated collagen gels; epidermal equivalents (EE
) were obtained by seeding keratinocytes on non-populated collagen gels. Af
ter. maturation and differentiation of the epidermis, SE and EE were expose
d to 50 or 100J/cm(2) UVA. Structural damage and total epidermal lipids wer
e analysed and diffusion of radioactive oestradiol was monitored 24 and 72
h post-irradiation.
Results: Twenty-four hours after UVA irradiation, a disorganization of the
living epidermis is observed. UVA also significantly reduced the skin barri
er function and led to an increase in phospholipid and in a decrease of cer
amide levels. However, both the structure and thr barrier function of SE we
re recovered 72h post-irradiation, thereby suggesting that an intrinsic rep
air process might exist within the irradiated SE.
Conclusion: This study provides a strong evidence that UVA radiation alters
both the epidermal and dermal structures, the synthesis of epidermal lipid
s, and the permeability of the human skin.