Kimura T, Doi K
Research Center, Nihon Nosan Kogyo Co., Ltd., Ibaraki, Japan.
Exp Anim. 1995 Oct;44(4):293-9. doi: 10.1538/expanim.44.293.
Dorsal skin reactions to irradiation with two different types of ultraviolet (UV) light sources (sunlight and artificial UV light) were investigated in hairless descendants of Mexican hairless dogs. The total energy dose of solar UV exposure and artificial UV irradiation was 90 kJ/m2 and 40 kJ/m2, respectively. Histological examinations were done up to 7 days after UV irradiation (7 DAI). At 1 DAI, the solar UV-exposed skin did not show marked changes, while artificial UV irradiated skin exhibited a visible erythematous reaction and prominent histological alterations such as epidermal thickening, appearance of sunburn cells and deformation elastic fibers. At 4 DAI of solar UV-exposure, the skin color became moderately dark and noticeable pigmentation developed in the epidermis. In contrast, at 4 DAI of artificial UV irradiation, there still remained moderate degeneration in the epidermis and dermis, and delayed tanning was weak. At 7 DAI of solar exposure, delayed suntan reactions became more prominent. Histologically, there were heavy pigmentation of melanin granules mainly in the stratum basale. On the other hand, artificial UV irradiated skin showed less pigmentation. Thus, solar exposure provoked remarkable pigmentation while artificial UV irradiation brought about severe sunburn reactions in the dorsal skin of hairless dogs.
在墨西哥无毛犬的无毛后代中，研究了背部皮肤对两种不同类型紫外线（UV）光源（阳光和人工紫外线）照射的反应。太阳紫外线暴露和人工紫外线照射的总能量剂量分别为90 kJ/m²和40 kJ/m²。在紫外线照射后7天（照射后7天，DAI）内进行组织学检查。在照射后1天，太阳紫外线照射的皮肤未显示明显变化，而人工紫外线照射的皮肤出现可见的红斑反应和明显的组织学改变，如表皮增厚、晒伤细胞出现和弹性纤维变形。在太阳紫外线照射后4天，皮肤颜色变得中度暗沉，表皮出现明显的色素沉着。相比之下，在人工紫外线照射后4天，表皮和真皮仍存在中度变性，延迟性晒黑较弱。在太阳照射后7天，延迟性晒黑反应变得更加明显。组织学上，主要在基底层有大量黑色素颗粒色素沉着。另一方面，人工紫外线照射的皮肤色素沉着较少。因此，太阳照射在无毛犬背部皮肤引起明显的色素沉着，而人工紫外线照射则导致严重的晒伤反应。
