Effects of simulated solar radiation on type I and type III collagens, collagenase (MMP-1) and stromelysin (MMP-3) gene expression in human dermal fibroblasts cultured in collagen gels

Abstract

Understanding the mechanisms responsible for photodamage to the skin is most important for dermatology, 3-D cultures have been used as tools to mimic the in vivo situation for several years. We irradiated such a system containing human dermal fibroblasts cultured in collagen gels, a well-known model considered to be a dermal equivalent, which reproduces the interaction between cells and the surrounding extracellular matrix. The effects of solar irradiation (315–800 nm) on the stead-state levels of the mRNAs of extracellular matrix components (type 1 and III collagens) and their degrading enzymes (interstitial collagenase, MMP-1 and stromelysin 1, MMP-3) were measured. Exposure to low levels of solar radiation (0–10 J cm 2 in the UVA, i.e. suberythemal UVA doses) caused a transient decrease in type 1 procollagen mRNA, an increase in MMP-mRNA, and no change in type III procollagen mRNA steady-state levels. These results describe the early changes in the connective tissue of the skin following exposure to low level solar stimulation, and may help explain the long-term changes in photodamaged skin.