Influence de l'héliodermie et du stress oxydant sur les fibres élastiques et sur le collagène (conséquences sur les propriétés mécaniques de la peau)

BESANCON-BU Médecine pharmacie (250562102) / SudocSudocFranceF

Le vieillissement cutané (caractérisation des capacités antioxydantes des fibroblastes et des kératinocytes humains en réponse à un stress photo-induit)

Les UV A et B participent au photovieillissement cutané en produisant un stress oxydant. Pour lutter contre ce stress, les kératinocytes et les fibroblastes cutanés possèdent un système de défenses antioxydantes. - La comparaison des capacités antioxydantes basales des fibroblastes de sujets jeunes et de sujets adultes fait apparaître des différences significatives : l'activité superoxyde dismutase est supérieure chez les fibroblastes de sujets jeunes et l'activité catalase y est inférieure. Les fibroblastes issus de sujets adultes sont les plus sensibles aux UVB. Les UV A provoquent une augmentation de la peroxydation lipidique au sein des fibroblastes concomitante à une activité superoxyde dismutase accrue. Chez les kératinocytes, les UV A engendrent une diminution de l'activité catalase. Des différences entre les systèmes de défenses antioxydantes des fibroblastes et des kératinocytes apparaissent après une irradiation UV A. Les kératinocytes se montrent alors plus résistants aux UV A.UV A and B take part in photoaging by producing an oxidative stress, and the cutaneous keratinocytes and fibroblasts present antioxidant defence system. The basal antioxidant capacities of fibroblasts from young and adult donors show significant differences : superoxide dismutase activity is higher in fibroblasts from young donors and catalase activity is lower there. The fibroblasts resulting from adult donors are most sensitive to the UVB. The UV A cause an increase in lipid peroxidation in fibroblasts concomitant to an increase in superoxide dismutase activity. On keratinocytes, the UV A generate a reduced catalase activity. Differences between antioxidant defence systems in fibroblasts and keratinocytes appear after an UV A irradiation. Then, keratinocytes appear more resistant to the UV A.BESANCON-BU Médecine pharmacie (250562102) / SudocSudocFranceF

Comparison of ultraviolet B-induced imbalance of antioxidant status in foreskin- and abdominal skin-derived human fibroblasts.

International audienceUltraviolet B radiation (UVB) is involved in the development of deleterious cutaneous damage. Several changes could be attributed to UVB-induced reactive oxygen species attacks in fibroblasts. However dermal cells from young and adult skin could respond differently to oxidative stress. So antioxidant status and its consequences on cytotoxicity and apoptosis were compared in child foreskin fibroblasts (FF) and adult abdominal skin fibroblasts (AF) in response to UVB. Basal levels of lipid peroxidation tended to be higher in AF than in FF, which could be related to a reshaping of antioxidant defences (higher catalase and lower superoxide dismutase activities). AF and FF appeared to react similarly to high UVB doses as regards cytotoxicity and apoptosis which increased significantly 24h after exposure. The enhancement of cell death could be due to the inherent oxidative stress: glutathione appeared significantly decreased in both cell populations. As a consequence AF, but not FF, presented significantly increased levels of lipid peroxidation, which could be explained by the pre-cited differences of basal antioxidant defences. These results suggest that AF and FF do not respond to UVB by the same pathway

A new tool to test active ingredient using lactic acid in vitro, a help to understand cellular mechanism involved in stinging test: An example using a bacterial polysaccharide (Fucogel ® )

International audienc