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Rôle des mélanocytes dans l'unité épidermique de mélanisation reconstruite ex-vivo après une irradiation UV aiguë

Abstract : Influence of melanocytes in skin pigmentation is well documented, however its photoprotective role is controvert. Role of melanocytes have been investigated on reconstructed epidermis with 100 % of keratinocytes or 95 % of keratinocytes and 5 % of melanocytes. In a first time, effect of an acute UVB dose has been studied on both reconstructs, next we have investigated UVA and UVA+B effects on these epidermis. Following irradiation, presence of melanocytes in reconstructed epidermis protects against apoptosis without protects significantly against DNA damage formation (CPD, 6-4PP) and protects against UV-induced unbalance of the SOD/catalase ratio (antioxidants enzymes). On the contrary, presence of melanocytes in reconstructed epidermis amplifies lipids and proteins oxidations but seems to protect against DNA oxidations. Melanocytes differ from keratinocytes by their melanin content and their more important concentration in polyunsaturated fatty acids. To evaluate what is the part of melanin and the part of polyunsaturated fatty acids in epidermal UV responses, reconstructed epidermis with keratinocytes have been supplemented with polyunsaturated fatty acid. This study indicates that polyunsaturated fatty acids are responsible for lipids and proteins oxidations and that melanin protect against DNA oxidation induced by lipoperoxidation. All these studies demonstrate that, model of reconstructed epidermis and epidermis in-vivo have the same behaviour following UV irradiation. In a last time, sunscreens and antioxidants have been tested on reconstructed epidermis and have demonstrated that model of reconstructed epidermis is suitable for photoprotective molecules screening.
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https://tel.archives-ouvertes.fr/tel-00194194
Contributor : Muriel Cario-Andre <>
Submitted on : Wednesday, December 5, 2007 - 9:11:47 PM
Last modification on : Friday, October 23, 2020 - 4:42:38 PM
Long-term archiving on: : Monday, April 12, 2010 - 6:18:51 AM

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  • HAL Id : tel-00194194, version 1

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Muriel Cario-Andre. Rôle des mélanocytes dans l'unité épidermique de mélanisation reconstruite ex-vivo après une irradiation UV aiguë. Biologie cellulaire. Université Victor Segalen - Bordeaux II, 2000. Français. ⟨tel-00194194⟩

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