ULTRAVIOLET-B WAVELENGTH DEPENDENCE FOR THE REGULATION OF 2 MAJOR MATRIX-METALLOPROTEINASES AND THEIR INHIBITOR TIMP-1 IN HUMAN DERMAL FIBROBLASTS (VOL 64, PG 649, 1996)

The wavelength dependence for the regulation of two major matrix-metal loproteinases, interstitial collagenase (MMP-1) and stromelysin-1 (MMP -3), and their major inhibitor, tissue inhibitor of metalloproteinases (TIMP-1), was studied in human dermal fibroblasts in vitro. Monochrom atic irradiation at 302, 307, 312 and 317 mn with intensities ranging from 20 to 300 J/m(2) increased MMP-1 and MMP-3 mRNA steady-state leve ls and the secretion of the corresponding proteins up to 4.4-fold, whe reas almost no increase was observed at wavelengths <290 nm. In contra st, the synthesis of TIMP-1 increased only marginally. This imbalance may contribute to the severe connective tissue damage related to photo aging of the skin. The wavelengths responsible for MMP-1 and MMP-3 ind uction reported here are distinct from the absorption spectrum of DNA and are different from results previously reported in the literature. Importantly, they overlap with wavelengths whose intensity is predicte d to increase on the earth's surface upon ozone depletion. Intensities and particular wavelengths used in our studies in vitro can be absorb ed readily by fibroblasts within the skin in vivo and, thus, are relev ant for risk assessment and development of protective agents.