title: Protective effect of the standardized green tea seed extract on UVB-induced skin photoaging in hairless mice.
abstract: OBJECTIVE
  Ultraviolet B (UVB) irradiation on skin can induce production of reactive oxygen species (ROS), which cause expression of matrix metalloproteinases (MMPs) and collagen degradation. Thus, chronic exposure of skin to UVB irradiation leads to histological changes consistent with aging, such as wrinkling, abnormal pigmentation, and loss of elasticity. We investigated the protective effect of the standardized green tea seed extract (GSE) on UVB-induced skin photoaging in hairless mice.
  
  
  METHODS
  Skin photoaging was induced by UVB irradiation on the back of Skh-1 hairless mice three times per week and UVB irradiation was performed for 10 weeks. Mice were divided into six groups; normal control, UVB irradiated control group, positive control (UVB + dietary supplement of vitamin C 100 mg/kg), GSE 10 mg/kg (UVB + dietary supplement of GSE 10 mg/kg), GSE 100 mg/kg (UVB + dietary supplement of GSE 100 mg/kg), and GSE 200 mg/kg (UVB + dietary supplement of GSE 200 mg/kg).
  
  
  RESULTS
  The dietary supplement GSE attenuated UVB irradiation-induced wrinkle formation and the decrease in density of dermal collagen fiber. In addition, results of the antioxidant analysis showed that GSE induced a significant increase in antioxidant enzyme activity compared with the UVB irradiation control group. Dietary supplementation with GSE 200 mg/kg resulted in a significant decrease in expression of MMP-1, MMP-3, and MMP-9 and an increase in expression of TIMP and type-1 collagen.
  
  
  CONCLUSIONS
  Findings of this study suggest that dietary supplement GSE could be useful in attenuation of UVB irradiation-induced skin photoaging and wrinkle formation due to regulation of antioxidant defense systems and MMPs expression.
authors.affiliation: Department of Biomaterials Science and Technology, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, Korea.
authors.forename: Jae-Youn
authors.initials: JY
authors.lastname: Lim
authors.affiliation: Department of Medical Nutrition, Graduate School of East-West Science, Kyung Hee University, Yongin, Gyeonggi 446-701, Korea.
authors.forename: Ok-Kyung
authors.initials: OK
authors.lastname: Kim
authors.affiliation: Department of Medical Nutrition, Graduate School of East-West Science, Kyung Hee University, Yongin, Gyeonggi 446-701, Korea.
authors.forename: Jeongmin
authors.initials: J
authors.lastname: Lee
authors.affiliation: NutriPlan Co., Ltd, Gyeonggi 410-837, Korea.
authors.forename: Min-Jae
authors.initials: MJ
authors.lastname: Lee
authors.affiliation: NutriPlan Co., Ltd, Gyeonggi 410-837, Korea.
authors.forename: Namgil
authors.initials: N
authors.lastname: Kang
authors.affiliation: Department of Biomaterials Science and Technology, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, Korea.
authors.forename: Jae-Kwan
authors.initials: JK
authors.lastname: Hwang
keywords: Green tea seed; MMPs; UVB irradiation; antioxidant; photoaging
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