Phillips T J, Bhawan J, Yaar M, Bello Y, Lopiccolo D, Nash J F
Department of Dermatology, Boston University Medical Center, and the Procter & Gamble Co, Sharon Woods Technical Center, Cincinnati, OH, USA.
J Am Acad Dermatol. 2000 Oct;43(4):610-8. doi: 10.1067/mjd.2000.107244.
Acute and chronic skin damage occurs as a consequence of solar UV radiation exposure. To diminish such skin damage, the dermatologic community advocates the daily use of sunscreens as part of a sun avoidance strategy.
We determined the effectiveness of a sunscreen product with a sunscreen protection factor (SPF) of 15 applied daily in preventing UV-induced histologic damage in human skin compared with the protection afforded by sunscreens with equal or higher SPF applied intermittently.
Twenty-four subjects were exposed to 2 minimal erythema doses of solar-simulated UV on 4 consecutive days. Three sunscreen products were applied to the buttock of each subject. One SPF 15 product was applied daily before exposure to UV and, to simulate intermittent product use, an SPF 15 or SPF 29 product was applied on 3 of 4 days, with one missed application on days 2, 3, or 4. Skin biopsy specimens were taken and processed for routine and immunohistochemical staining. Changes in number of sunburn cells and Langerhans cells as well as degree of inflammatory infiltrate and lysozyme immunostaining were determined.
There was a statistically significant increase in the number of sunburn cells, degree of inflammation, and intensity of lysozyme staining, and there was a decrease in the number of Langerhans cells at sites where sunscreen application was missed as compared with unirradiated control and daily SPF 15 sunscreen-treated sites.
Our data suggest that daily use of a sunscreen reduces the skin damage produced by UV exposure compared with intermittent use of equal or higher SPF products. The daily application of sunscreens in appropriate quantities reduces the harmful effects of solar UV radiation on skin. Compliance is essential for maximal benefit of sunscreens.
急性和慢性皮肤损伤是太阳紫外线辐射暴露的结果。为了减少此类皮肤损伤，皮肤科界提倡将每日使用防晒霜作为防晒策略的一部分。
我们确定了一款防晒保护系数（SPF）为15的防晒霜产品每日使用在预防紫外线引起的人体皮肤组织学损伤方面的有效性，并与间歇性使用同等或更高SPF值的防晒霜所提供的保护效果进行比较。
24名受试者连续4天接受相当于2个最小红斑量的模拟太阳紫外线照射。三种防晒霜产品分别涂抹于每位受试者的臀部。一种SPF 15的产品在紫外线照射前每日涂抹，为模拟间歇性使用产品，在4天中的3天涂抹一种SPF 15或SPF 29的产品，在第2、3或4天漏涂一次。采集皮肤活检标本并进行常规和免疫组织化学染色处理。测定晒伤细胞和朗格汉斯细胞数量的变化以及炎症浸润程度和溶菌酶免疫染色情况。
与未照射的对照部位和每日使用SPF 15防晒霜处理的部位相比，在漏涂防晒霜的部位，晒伤细胞数量、炎症程度和溶菌酶染色强度有统计学意义的增加，而朗格汉斯细胞数量减少。
我们的数据表明，与间歇性使用同等或更高SPF值的产品相比，每日使用防晒霜可减少紫外线暴露产生的皮肤损伤。适量每日涂抹防晒霜可减少太阳紫外线辐射对皮肤的有害影响。为使防晒霜发挥最大益处，坚持使用至关重要。
