Only 5% of the sun´s radiation that hits the earth is UV-rays. However, this has unexpected strength. There are different forms of UV rays. UVC rays are blocked by the ozone layer. UVA and UVB rays reach the surface of the earth and affect our skin. UVA rays: A as in “Aging” or “Allergies”.
They are there the whole year round, even on cloudy days: 95% of ultraviolet rays that reach the earth´s surface are UVA rays. They pass through clouds, glass and also the epidermis. In contrast to UVB rays, they do not cause any painful symptoms on the skin, however they do penetrate very deep into the skin to the cells of the dermis. Primarily, they produce free radicals, can permanently change cells and lead to the following changes. The simplified scientific explanation is as follows: In the skin, intracellular cell-to-cell communication (CCC) takes place via cell-cell canals (gap junctions), which is important for various cellular functions such as the regulation of growth, differentiation and the development of cells. The loss of the CCC is a characteristic of most cancer cells. UVA radiation is known to be a cell stressor. This work showed that UVA radiation inhibits CCC in human skin fibroblasts by about 30 %. Treatment with carotenoids (ß-carotene, astaxanthin, canthaxanthin) protects the cells from UVA-radiation-induced inhibition of the CCC. This supports the hypothesis that carotenoids can be used in humans as an endogenic sun protective agent.
Title: Effects of astaxanthin and canthaxanthin on the cell-cell-communication via Gap Junctions.