Chaqour B, Bellon G, Seite S, Borel J P, Fourtanier A
Laboratoire de Biochimie, CNRS ERX084, Faculté de Médecine, Reims, France.
J Photochem Photobiol B. 1997 Jan;37(1-2):52-9. doi: 10.1016/s1011-1344(96)07399-x.
All-trans-retinoic acid (t-RA) can repair some of the tissue damage caused by chronic exposure of skin to UV radiation. In the present study, we have investigated its effect on collagen and collagenase gene expression in hairless mouse skin. Hairless mice (SKH-hr 1) were irradiated dorsally with increasing doses of UVB radiation (total, 4.8 J cm-2) for 10 weeks. The animals were then topically treated with 0.05% t-RA dissolved in a vehicle or with the vehicle alone three times a week for up to 10 weeks. Non-irradiated animals underwent the same treatment. In our experimental conditions, UVB irradiation alone induced no changes in type I, III and VI collagen mRNA levels in dorsal and ventral skin. The mRNA level of collagenase I was also unchanged. Topically applied t-RA increased the steady state levels of type I and III collagen mRNA in irradiated and non-irradiated dorsal skin. The mean increase was about 2.2- and 2.7-fold in non-irradiated skin and 2.4- and 2.5-fold in irradiated skin for type I and III collagen mRNA respectively. The increase in irradiated skin was partly due to the vehicle alone, which exerted a stimulating effect on the steady state levels of alpha 1(I) and alpha 1(III) mRNA. The mRNA level of type VI collagen was also significantly increased by t-RA, but only in irradiated skin. The mRNA level of collagenase was significantly decreased only in irradiated t-RA-treated skin. In addition, t-RA exerted a systemic effect because the mRNA levels of collagen were enhanced by factors of 1.9 and 2.5 for alpha 1(I) and 2.0 and 2.0 for alpha 1(III) in the ventral skin of irradiated and non-irradiated animals respectively. This study leads to the conclusion that topical t-RA exerts directly and/or indirect effects on the expression of collagen genes in irradiated and non-irradiated hairless mouse skin.
全反式维甲酸（t-RA）能够修复皮肤长期暴露于紫外线辐射所造成的部分组织损伤。在本研究中，我们调查了其对无毛小鼠皮肤中胶原蛋白及胶原酶基因表达的影响。对无毛小鼠（SKH-hr 1）背部进行递增剂量的UVB辐射（总量为4.8 J/cm²），持续10周。然后，每周三次给这些动物局部涂抹溶解于赋形剂中的0.05% t-RA或仅涂抹赋形剂，持续10周。未接受辐射的动物接受相同处理。在我们的实验条件下，单独的UVB辐射并未引起背部和腹部皮肤中I型、III型和VI型胶原蛋白mRNA水平的变化。I型胶原酶的mRNA水平也未改变。局部应用t-RA增加了辐射及未辐射的背部皮肤中I型和III型胶原蛋白mRNA的稳态水平。在未辐射皮肤中，I型和III型胶原蛋白mRNA的平均增加倍数分别约为2.2倍和2.7倍；在辐射皮肤中，分别为2.4倍和2.5倍。辐射皮肤中的增加部分归因于赋形剂本身，其对α1(I)和α1(III) mRNA的稳态水平具有刺激作用。VI型胶原蛋白的mRNA水平也因t-RA而显著增加，但仅在辐射皮肤中。胶原酶的mRNA水平仅在接受t-RA处理的辐射皮肤中显著降低。此外，t-RA具有全身效应，因为在辐射及未辐射动物的腹部皮肤中，α1(I)的胶原蛋白mRNA水平分别提高了1.9倍和2.5倍，α1(III)分别提高了2.0倍和2.0倍。本研究得出结论，局部应用t-RA对辐射及未辐射的无毛小鼠皮肤中胶原蛋白基因的表达具有直接和/或间接影响。
