14 This particular profile maximizes the surface to volume ratio and thus may expedite diffusion and exchange. Human erythrocytes are well known for their unique biconcave shape owing to a special organization of the membrane-skeleton system. 10 Several physiological and pathological effects could be traced back to the generation of reactive oxygen species (ROS) by UVA irradiation. 9 A recent study identified a UVA-specific phototransduction pathway in melanocytes that induces rapid calcium mobilization via transient receptor potential A1 ion channels.
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7, 8 UVA therapy is also an effective treatment for acute graft-versus-host disease of the skin. 1– 6 For instance, whole-body UVA irradiation results in a significant drop of blood pressure owing to release of nitric oxide from intracutaneous photolabile nitric oxide derivates. Long-wavelength ultraviolet-A (UVA, 320~400 nm) light, having deeper penetration and lower phototoxicity than short-wavelength UV light (200~320 nm), is known to have various positive effects for human health. Ultraviolet (UV) light has an important role for life on earth. Taken together, these results demonstrate that 365 nm UVA irradiation can protect the biconcave profile of human erythrocytes through membrane-skeleton enhancement associated with a production of oxidants. The oxidants hydrogen peroxide and cumene hydroperoxide partly simulate the protective effects. Interestingly, at two irradiation doses of UVA pretreatment, erythrocytes still seem to exhibit cell viability as tested by trypan blue assay even if distilled water or saponin is added. This protective effect can also be confirmed for saponin that damages the membrane-skeleton by vesiculation and pore formation. Depending on the irradiation dose, UVA show protection of the biconcave profile against the detrimental action of distilled water.
![cell stereology trypan blue cell stereology trypan blue](https://slidetodoc.com/presentation_image/9842388054163bbd8a1bc0773a43212e/image-9.jpg)
![cell stereology trypan blue cell stereology trypan blue](https://d2jx2rerrg6sh3.cloudfront.net/image-handler/picture/2020/4/art2-7.jpg)
In the present work, we use a simple irradiation method to treat human erythrocytes with 365 nm ultraviolet-A (UVA) light at the single-cell level in vitro. To perform various physiological functions, erythrocytes possess a unique biconcave shape provided by a special architecture of the membrane-skeleton system.