Figure 4.
UV irradiation induces gene expression of MMP-1, MMP-3, and MMP-9 primarily in human epidermis in vivo. Sun-protected buttock skin of healthy adult human volunteers was exposed to twice the minimum erythema dose of solar-simulated UV irradiation (SPEC 450W xenon arc solar simulator). Full thickness (4mm) biopsies were obtained 24 hours post irradiation as described in Figure 1 legend. Total RNA were extracted from epidermis and dermis, which were obtained by laser capture microdissection. MMP-1, MMP-3, and MMP-9 mRNA levels were determined by real-time RT-PCR, as described in Figure 1 legend. Results are means±SEM of MMPs mRNA normalized to 36B4 (internal control) mRNA. N=6, p<0.05.