Protection effect for collagen artificial skin of UV-cut materials in Antarctica

Abstract

In the Antarctica during mid-summer being appropriate for a severe environment of UV-rays, the authors surveyed the protective effect of UV-cut materials against UV-rays, using a collagen sheet (hereafter "collagen artificial skin") that was covered with a UV-cut film and subjected to exposure outdoors. First, exposure of the laminated, collagen artificial skin not covered with any film to UV-rays caused the extracts from the 1st layer, i.e. the utmost outer-layer, of the collagen artificial skin to increase the terminal amino group concentration up to as high as 3.20 nmol/ml, since the collagen molecular chain was largely cut. On the other hand, for the 2nd and 3rd layers of the said sheet, the terminal amino group concentrations were found to have decreased in order, and for the 4th layer and onward, the concentrations were shown to have decreased down to 0.22 nmol/ml, which were nearly equal to the level before the exposure. Although the bands of three molecular chains of α-, β-, and γ-chains in all samples after exposure to UV-rays were disappeared, it was also shown that the more a layer was inside, the less the collagen molecular chain was not dissolved. In addition, when the collagen artificial skin covered with a UV-blocking, zinc oxide-added film was exposed to the sunlight, it was demonstrated that the more the addition of zinc oxide in the film increased, the lower the terminal amino group concentration in the extracts from the exposed, collagen artificial skin was observed. At the time when the added quantity of zinc oxide reached 0.40v%, the concentration was maintained almost at the same level as observed prior to the exposure. Also in comparison with UV-protecting agents, it was shown that the film added with an organic compound acting as a UV-absorbing agent reduced most the damages sustained by UV-rays. As described above, the evaluation method using a collagen artificial skin could be effectively employed in outdoor exposure for examining the protective effect of UV-cut materials to the skin against the UV-rays in the Antarctica.