Kimura T, Doi K
Research Center, Nihon Nosan Kogyo Co Ltd, Ibaraki, Japan.
Am J Vet Res. 1994 Feb;55(2):199-203.
Responses of the skin over the dorsum to solar UV irradiation (2 hours/d for 6 consecutive days) were investigated in hairless descendants of Mexican hairless dogs. Assessment of skin color changes, using a spectrophotometer, indicated that luminance values began to decrease from the third day of UV irradiation, reached the minimal value at 3 weeks, and almost recovered 12 weeks after completion of UV irradiation. The number of the dihydroxyphenylalanine-positive melanocytes increased significantly (P < 0.01) from the third day of UV irradiation, reached its maximal value at 2 weeks, and recovered to normal at 12 weeks after completion of UV irradiation. On the second day of UV irradiation, the epidermis became focally thick, with disarrangement of component cells that had degenerative changes. In addition, a few so-called sunburn cells with pyknotic nuclei were seen in the epidermis. On the third day of UV irradiation, apparent suntan reaction developed, and a large number of epithelial cells in the epidermis were heavily pigmented with melanin granules. At 12 weeks after completion of UV irradiation, the epidermis appeared almost normal. On the other hand, significant changes were not detected in the dermis throughout the study.
在墨西哥无毛犬的无毛后代中，研究了背部皮肤对太阳紫外线照射（连续6天，每天照射2小时）的反应。使用分光光度计评估皮肤颜色变化，结果表明，从紫外线照射的第三天起，亮度值开始下降，在3周时达到最小值，在紫外线照射结束12周后几乎恢复。从紫外线照射的第三天起，二羟基苯丙氨酸阳性黑素细胞数量显著增加（P < 0.01），在2周时达到最大值，并在紫外线照射结束12周后恢复正常。在紫外线照射的第二天，表皮局部增厚，组成细胞排列紊乱，出现退行性变化。此外，在表皮中可见少数核固缩的所谓晒伤细胞。在紫外线照射的第三天，出现明显的晒黑反应，表皮中的大量上皮细胞被黑色素颗粒大量色素沉着。在紫外线照射结束12周后，表皮几乎恢复正常。另一方面，在整个研究过程中，真皮未检测到明显变化。
