UV IRRADIATION INDUCES THE EXPRESSION OF GELATINASES IN HUMAN SKIN IN-VIVO

UV irradiation results in marked changes in skin connective tissue, su ch as degeneration of collagen, and abnormal elastosis. The mechanism of connective tissue damage by UV has not been clarified in detail. In the present study the mechanism of actinic damage was studied by assa ying gelatinases, 72-kDa (MMP-2) and 92-kDa (MMP-9), from suction blis ter fluids induced on patients who had received either UVB or PUVA tre atments. The results indicate that both UVB and PUVA increase the leve ls of gelatinases in human skin. By in situ hybridization, it was also possible to show that UV irradiation induced increased levels of gela tinase mRNAs in fibroblasts. Furthermore, in samples from severe actin ic damage, gelatinase mRNAs were abundantly present, suggesting that g elatinases may contribute to photodamage.