Moloney S J, Edmonds S H, Giddens L D, Learn D B
Department of Skin Biology Research, Schering-Plough Healthcare Products Inc., Memphis, TN 38151.
Photochem Photobiol. 1992 Oct;56(4):505-11. doi: 10.1111/j.1751-1097.1992.tb02194.x.
Quantitative and qualitative changes in dermal collagen and elastin occur in response to chronic ultraviolet (UV) irradiation. These changes have been implicated in the genesis of the wrinkling seen in chronically irradiated, or photoaged skin. We examined the relationship between wrinkle formation and changes in dermal structural protein content and type. Skh-1 hairless mice were irradiated with suberythemal doses of UV-B three times a week for up to 20 wk. Visible wrinkling was present after 6-7 wk of irradiation. Dermal elastic fiber content was quantified by color image analysis of paraffin-embedded tissue. There was no significant difference in dermal elastic fiber content between irradiated and age-matched control mice after either 10 or 20 wk of irradiation. The effect of UV-B irradiation on total dermal collagen content, ratio of collagen type III-type I, and extent of glycosylation and crosslinking of collagen was no different in irradiated and age-matched control mice after 10 wk of irradiation. Increased epidermal thickness was evident in frozen sections after 6 wk of irradiation, and the thickness increased with continued irradiation. Dermal thickening was evident after 10 wk of irradiation. Sufficient UV-B irradiation will eventually cause changes in dermal elastin and collagen content; however, wrinkle formation precedes such changes. A causal relationship between wrinkle formation and dermal structural protein content changes in Skh-1 hairless mice could not be established in this study.
皮肤中的胶原蛋白和弹性蛋白会因长期紫外线（UV）照射而发生定量和定性变化。这些变化与长期受照皮肤（即光老化皮肤）中出现的皱纹形成有关。我们研究了皱纹形成与真皮结构蛋白含量及类型变化之间的关系。对Skh-1无毛小鼠每周进行3次亚红斑剂量的UV-B照射，持续长达20周。照射6-7周后出现明显皱纹。通过对石蜡包埋组织进行彩色图像分析来定量真皮弹性纤维含量。照射10周或20周后，照射组小鼠与年龄匹配的对照小鼠之间的真皮弹性纤维含量无显著差异。照射10周后，照射组小鼠与年龄匹配的对照小鼠在UV-B照射对真皮总胶原蛋白含量、III型与I型胶原蛋白比例以及胶原蛋白糖基化和交联程度的影响方面没有差异。照射6周后，冰冻切片中可见表皮增厚，且随着照射持续增厚加剧。照射10周后可见真皮增厚。足够的UV-B照射最终会导致真皮弹性蛋白和胶原蛋白含量发生变化；然而，皱纹形成先于这些变化。在本研究中，无法确定Skh-1无毛小鼠皱纹形成与真皮结构蛋白含量变化之间的因果关系。
