Ota T, Hanada K, Hashimoto I
Department of Dermatology, Hirosaki University School of Medicine, Japan.
Photochem Photobiol. 1996 Dec;64(6):984-7. doi: 10.1111/j.1751-1097.1996.tb01865.x.
The effect of cold stress on skin damage caused by UVB irradiation was investigated both in vivo and in vitro. Ear skin of mice that had been exposed to cold stress at 0 degree C for 20 min and at 5 degrees C for 24 h was exposed to UVB radiation. Sunburn cell production was less in mice exposed to the lower temperature. In addition, the effect of cold stress on the survival rate of UVB-irradiated rat keratinocytes was examined in a cytotoxicity test, with the results showing that keratinocytes exposed to cold stress of 0 degree C had a higher survival rate than control cells. To pursue a promising clue for explaining the result, we examined metallothionein (MT) production in rat keratinocytes that had been exposed to cold stress at 0 degree C. Microfluorometric quantification showed a positive correlation between the time course and the intensity of immunofluorescence for MT, indicating that the molecule is inducible by exposure to cold stress in our experimental system. These results suggest that epidermal cells that have been exposed to cold stress maintain a higher resistance to UV radiation than nonexposed controls in vivo and in vitro, and that MT with radical-scavenging activity might contribute, at least in part, to photoprotection against UVB-induced oxidative damage in mammalian skin.
在体内和体外研究了冷应激对紫外线B（UVB）照射所致皮肤损伤的影响。将小鼠耳部皮肤在0℃暴露于冷应激20分钟，在5℃暴露24小时后，再进行UVB辐射。暴露于较低温度的小鼠中晒伤细胞的产生较少。此外，在细胞毒性试验中检测了冷应激对UVB照射的大鼠角质形成细胞存活率的影响，结果显示暴露于0℃冷应激的角质形成细胞比对照细胞具有更高的存活率。为了寻找解释该结果的有价值线索，我们检测了在0℃暴露于冷应激的大鼠角质形成细胞中金属硫蛋白（MT）的产生。微量荧光定量显示MT免疫荧光的时间进程与强度之间呈正相关，表明在我们的实验系统中该分子可被冷应激诱导。这些结果表明，在体内和体外，暴露于冷应激的表皮细胞比未暴露的对照细胞对紫外线辐射具有更高的抗性，并且具有自由基清除活性的MT可能至少部分有助于对哺乳动物皮肤中UVB诱导的氧化损伤的光保护作用。
