Effect of UVA or UVB Irradiation on Cutaneous Lipids in Films or in Solution

Abstract

The barrier function of the skin is largely due to the stratum corneum which is essentially composed of lipids. Different external factors, such as UV irradiation, affect this skin layer and are responsible for a destabilization of the supramolecular organization of its constituted lipids. In this work, mass spectrometry and infrared spectroscopy are combined to study the correlation between the formation of oxidative compounds by UV irradiation and the lipid organization. Experiments were carried out on unsaturated lipids in film or solution form, exposed to UVA or UVB irradiation. UV exposure leads to the formation of oxygenated entities in the case of lipids with an unsaturated fatty acid moiety, resulting in a decrease in their packing which is greater when the lipids are in solution. The packing decrease is even greater following UVB irradiation.

UVB Radiation Variably Affects n‐3 Fatty Acids but Elevated Temperature Reduces n‐3 Fatty Acids in Juvenile Atlantic Salmon (Salmo salar)

“…For example, sea lice (Lepeophtheirus salmonis) infections of cultured Atlantic Salmon are highest in summer and/or in shallow bays when temperatures are warmest [49]. The barrier functions of the skin are primarily a consequence of the lipid composition of the stratum corneum [50], therefore, we suggest that the increases in specific individual FA that we observed as a function of increasing temperature may represent a generalized defense response to the increased risk of parasite infection when salmon are raised in water temperatures that are above their optimal growth temperatures.…”

“…UV-induced damage including, for example, sunburn [51,52] and reduced numbers of mucous secreting goblet cells [15] have been observed in some fish species, whereas other species appear to benefit from protective substances in their skin [53,54]. Lipids in the outermost layer of skin (stratum corneum) are affected by UV exposure in three ways; (1) b scission (fragmentation of the carbon chain), (2) hydrogenation of the double bond of unsaturated compounds and (3) formation of oxygenated entities from unsaturated lipids [50]. In our experiments, the FA composition of dorsal and ventral skin tissues were largely unaffected by UV exposure.…”

Triptolide suppresses ultraviolet B-enhanced sebum production by inhibiting the biosynthesis of triacylglycerol in hamster sebaceous glands in vivo and in vitro

“…In addition, UVB-irradiation has been reported to increase sebum secretion and production in humans and hamsters in vivo (9)(10)(11). Furthermore, UVB exposure has been reported to facilitate free radical-mediated lipid peroxidation of sebum in the skin (10,12). Therefore, sunscreen or topical and systemic administration of antioxidants is likely to be an efficient strategy for preventing the UV-mediated perturbation of cutaneous barrier functions (13).…”

Plasma Induced Changes in Human Lipid Composition as Revealed through XPS-Analysis

“…The irradiance specifies the emitted power per area from a lighting source, in this case from a plasma discharge. In medical application, the emitted radiation in the UV-range has a primary importance, since its dose depending positive or negative effects on humans [24] [25]. The irradiance was recorded in the units mW/m 2 by applying the radiometer X1-1 (Gigahertz-Optik, Tuerkenfeld, Germany) and an absolute calibrated detector head UV-3719-4a(z).…”