). The MMPs are a large family
of zinc-dependent endoproteases with a broad range of substrate
specificities that are capable of degrading all extracellular matrix proteins (ECMs) (Kim et al., 2006). Aging and irradiation accelerate
the degradation of the extracellular matrix, resulting in a decrease
in dermal collagen and an increase in the level of matrix MMP-1,
which cleaves interstitial collagen