Jeon S E, Choi-Kwon S, Park K A, Lee H J, Park M S, Lee J H, Kwon S B, Park K C
Department of Dermatology, Seoul National University College of Medicine, Korea.
Photodermatol Photoimmunol Photomed. 2003 Oct;19(5):235-41. doi: 10.1034/j.1600-0781.2003.00052.x.
The aim of this study was to investigate the effects of dietary supplementation with (+)-catechin on cutaneous antioxidant enzymes and the skin damage caused by UVB irradiation.
BALB/c mice were divided into three groups. Each group was fed a regular diet (RD) or a 2% catechin-supplemented diet for either 2 weeks (2CSD) or 4 weeks (4CSD) ad libitum prior to UVB irradiation. Skin was removed for the antioxidant enzyme assay, hematoxylin and eosin staining, and the TEM analysis before and at various time points after UVB (200 mJ/cm2) irradiation.
Before UVB irradiation, the superoxide dismutase (SOD) and catalase (CAT) activities of the 2CSD and the 4CSD groups were found to be lower than those of the RD group, whereas the glutathione peroxidase (GPx) activity of the 4CSD group was higher than those of the RD and the 2CSD groups (P<0.05). The SOD and CAT activities of the RD group decreased after UVB irradiation, while those of the 2CSD and the 4CSD groups increased immediately after irradiation and then decreased (P<0.05). Immediately after UVB irradiation, the GPx activities of the 4CSD and the 2CSD groups increased, but that of the RD group decreased. The GPx activity of all three groups showed a tendency to return to pre-UVB irradiation levels with time. Light microscopic findings of the RD group showed epidermal thinning and apoptotic cells at 24 h after UVB irradiation and mostly necrotic cells at 48 h, whereas only moderate thickening of the epidermis was observed in the 2CSD group at 48 h after irradiation. An electron microscopic examination produced similar findings. At 48 h after irradiation, nearly all epidermal cells seemed to be damaged in the RD group as compared to the 2CSD group.
These results demonstrate that dietary supplementation with (+)-catechin could protect epidermal cells against UVB-induced damage by modulating antioxidant enzyme activities.
本研究旨在探讨膳食补充（+）-儿茶素对皮肤抗氧化酶以及紫外线B（UVB）照射所致皮肤损伤的影响。
将BALB/c小鼠分为三组。在UVB照射前，每组小鼠随意进食常规饮食（RD）或含2%儿茶素的饮食2周（2CSD）或4周（4CSD）。在UVB（200 mJ/cm2）照射前及照射后的不同时间点，取皮肤进行抗氧化酶测定、苏木精-伊红染色及透射电镜分析。
在UVB照射前，发现2CSD组和4CSD组的超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性低于RD组，而4CSD组的谷胱甘肽过氧化物酶（GPx）活性高于RD组和2CSD组（P<0.05）。UVB照射后，RD组的SOD和CAT活性降低，而2CSD组和4CSD组的SOD和CAT活性在照射后立即升高，随后降低（P<0.05）。UVB照射后立即观察到，4CSD组和2CSD组的GPx活性升高，而RD组的GPx活性降低。随着时间的推移，三组的GPx活性均呈现出恢复到UVB照射前水平的趋势。RD组的光镜检查结果显示，UVB照射后24小时表皮变薄且出现凋亡细胞，48小时大多为坏死细胞，而2CSD组在照射后48小时仅观察到表皮适度增厚。电镜检查结果相似。照射后48小时，与2CSD组相比，RD组几乎所有表皮细胞似乎均受损。
这些结果表明，膳食补充（+）-儿茶素可通过调节抗氧化酶活性来保护表皮细胞免受UVB诱导的损伤。
