Processes Leading to Wrinkles. In response to this sun-induced elastin accumulation, large amounts of enzymes called metalloproteinases are produced. The normal function of these metalloproteinases is generally positive, to remodel the sun-injured tissue by manufacturing and reforming collagen. This is an imperfect process, however, and some of these enzymes actually degrade collagen. Repetition of this imperfect skin rebuilding over and over again causes wrinkles.
Ozone is a particular problem.
Ozone depletion in the upper atmosphere, however, is increasing. This allows greater amounts of damaging UV rays to reach the surface of the earth and is associated with higher incidences of skin cancers, including melanoma.