Protective effect of the standardized green tea seed extract on UVB-induced skin photoaging in hairless mice

Abstract

Background/objectives: 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.

Materials/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.

Keywords: Green tea seed; MMPs; UVB irradiation; antioxidant; photoaging.

Fig. 1

Representative images of macroscopic morphological observation on skin of UVB-induced hairless mice after a 10-week experiment to evaluate the inhibitory effect of green tea seed extract (GSE). Normal control, No treatment group; Control, UVB-irradiated control group; Vit C, UVB irradiation with dietary supplement of vitamin C 100 mg/kg; GSE 10 mg/kg, UVB irradiation with dietary supplement of green tea seed extract 10 mg/kg; GSE 100 mg/kg, UVB irradiation with dietary supplement of green tea seed extract 100 mg/kg; GSE 200 mg/kg, UVB irradiation with dietary supplement of green tea seed extract 200 mg/kg.

Fig. 2

Representative images of histological observation by H&E staining on skin of UVB-induced hairless mice after a 10-week experiment to evaluate the inhibitory effect of green tea seed extract (GSE). Normal control, No treatment group; Control, UVB-irradiated control group; Vit C, UVB irradiation with dietary supplement of vitamin C 100 mg/kg; GSE 10 mg/kg, UVB irradiation with dietary supplement of green tea seed extract 10 mg/kg; GSE 100 mg/kg, UVB irradiation with dietary supplement of green tea seed extract 100 mg/kg; GSE 200 mg/kg, UVB irradiation with dietary supplement of green tea seed extract 200 mg/kg.

Fig. 3

Effects of green tea seed extract (GSE) on serum superoxide dismutase activity of UVB-induced photoaging in hairless mice. Normal control, No treatment group; Control, UVB-irradiated control group; Vit C, UVB irradiation with dietary supplement of vitamin C 100 mg/kg; GSE 10 mg/kg, UVB irradiation with dietary supplement of green tea seed extract 10 mg/kg; GSE 100 mg/kg, UVB irradiation with dietary supplement of green tea seed extract 100 mg/kg; GSE 200 mg/kg, UVB irradiation with dietary supplement of green tea seed extract 200 mg/kg. Values are expressed as mean ± SD of eight mice. Different letters show a significant difference at P < 0.05 as determined by Duncan's multiple range test.

Fig. 4

Effects of green tea seed extract (GSE) on catalase activity of UVB-induced photoaging in hairless mice. Normal control, No treatment group; Control, UVB-irradiated control group; Vit C, UVB irradiation with dietary supplement of vitamin C 100 mg/kg; GSE 10 mg/kg, UVB irradiation with dietary supplement of green tea seed extract 10 mg/kg; GSE 100 mg/kg, UVB irradiation with dietary supplement of green tea seed extract 100 mg/kg; GSE 200 mg/kg, UVB irradiation with dietary supplement of green tea seed extract 200 mg/kg. Values are expressed as mean ± SD of eight mice. Different letters show a significant difference at P < 0.05 as determined by Duncan's multiple range test.

Fig. 5

Effects of green tea seed extract (GSE) on glutathione peroxidase (GPx) activity of UVB-induced photoaging in hairless mice. Normal control, No treatment group; Control, UVB-irradiated control group; Vit C, UVB irradiation with dietary supplement of vitamin C 100 mg/kg; GSE 10 mg/kg, UVB irradiation with dietary supplement of green tea seed extract 10 mg/kg; GSE 100 mg/kg, UVB irradiation with dietary supplement of green tea seed extract 100 mg/kg; GSE 200 mg/kg, UVB irradiation with dietary supplement of green tea seed extract 200 mg/kg. Values are expressed as mean ± SD of eight mice. Different letters show a significant difference at P < 0.05 as determined by Duncan's multiple range test.