Dissanayake N S, Greenoak G E, Mason R S
Department of Physiology, University of Sydney, NSW, Australia.
J Cell Physiol. 1993 Oct;157(1):119-27. doi: 10.1002/jcp.1041570116.
The effects of UVA, mixed UVA + B, and solar-simulated irradiation were examined in human keratinocytes and melanocytes cultured in vitro. Irradiation with UVA, UVA + B, or the solar simulator caused a dose-dependent decrease in keratinocyte cell numbers and thymidine incorporation at 24 hours, with recovery after 48 and 72 hours. Divided dose regimens reduced the inhibitory effect of ultraviolet (UV) irradiation on cell numbers measured 24 hours after the last irradiation. Exposure to both UVA and UVA + B increased formation of cornified envelopes. Similar irradiance doses of UVA 80 minutes (1.12 J/cm2) and UVA + B 40 minutes (1.04 J/cm2) caused 2.4- and 3.3-fold increases in cornified envelope formation, respectively. With solar-simulated irradiation, the cornified envelope formation was increased by 3.5-fold after exposure of 8 minutes (2.6 J/cm2). Irradiation of melanocytes with UVA, UVA + B, or solar-simulated irradiation resulted in a dose-dependent decrease in melanocyte numbers after 24 hours compared with sham-irradiated controls. As a result of UV irradiation, tyrosinase activity of melanocytes measured at 24 hours was stimulated. UVA + B irradiation (1.04 J/cm2) increased tyrosinase activity approximately twofold, while UVA alone (1.1 J/cm2) increased tyrosinase four to sixfold and solar-simulated irradiation (1.3 J/cm2) increased tyrosinase approximately twofold compared to the control cells. Melanin content increased in cells after both UVA and mixed UVA + B irradiation. These results indicate that both UVA and mixed UVA + B irradiation had qualitatively similar effects on the proliferative and functional activity of skin-derived cells but that the type of irradiation and the dosage regimen affect the dose-response relationship.
在体外培养的人角质形成细胞和黑素细胞中检测了UVA、UVA + B混合光以及太阳模拟辐射的影响。用UVA、UVA + B或太阳模拟器照射后，角质形成细胞数量和24小时胸苷掺入量呈剂量依赖性下降，48小时和72小时后恢复。分次照射方案降低了紫外线（UV）照射对末次照射后24小时所测细胞数量的抑制作用。暴露于UVA和UVA + B均增加了角质化包膜的形成。UVA照射80分钟（1.12 J/cm2）和UVA + B照射40分钟（1.04 J/cm2）的相似辐照剂量分别使角质化包膜形成增加了2.4倍和3.3倍。太阳模拟辐射下，照射8分钟（2.6 J/cm2）后角质化包膜形成增加了3.5倍。与假照射对照组相比，用UVA、UVA + B或太阳模拟辐射照射黑素细胞24小时后，黑素细胞数量呈剂量依赖性减少。紫外线照射的结果是，24小时所测黑素细胞的酪氨酸酶活性受到刺激。与对照细胞相比，UVA + B照射（1.04 J/cm2）使酪氨酸酶活性增加约两倍，单独UVA照射（1.1 J/cm2）使酪氨酸酶活性增加四至六倍，太阳模拟辐射（1.3 J/cm2）使酪氨酸酶活性增加约两倍。UVA照射和UVA + B混合照射后细胞中的黑色素含量均增加。这些结果表明，UVA和UVA + B混合照射对皮肤来源细胞的增殖和功能活性具有定性相似的影响，但照射类型和剂量方案会影响剂量反应关系。
