## 3 Results
### Effects of UAE on UVB-Induced Skin Wrinkle Formation and Skin Moisturization  
To examine the effects of UAE on wrinkle formation in UVB-irradiated skin, the length and depth of skin wrinkles were measured using the replica of the dorsal back skin. Notably, exposure to UVB radiation resulted in significant skin wrinkles, which were mitigated by oral administration of either UAE or L-AA (Figure 2A). Moreover, the mean skin length(mm) and depth (\(\upmu\)m) after exposure to UVB (0.71 \(\pm\) 0.08 mm and 102.18 \(\pm\) 16.70 \(\upmu\)m, respectively) were markedly elevated in contrast to the intact control (0.28 \(\pm\) 0.07 mm, and 29.64 \(\pm\) 12.03 \(\upmu\)m, respectively). However, both UAE and L-AA significantly suppressed the formation of skin wrinkles in terms of length and depth (Figure 2B,C). Maintaining proper skin moisture is essential to protect skin from UVB-irradiated skin damage. UVB irradiation evidently decreased the skin water contents in the skin sample (13.22 \(\pm\) 2.24%) compared to the intact control (35.95% \(\pm\) 6.83%), which was significantly restored by both UAE and L-AA (Figure 2D). Hyaluronic acid and COL1 are key molecules that prevent skin wrinkle formation and maintain skin moisture. UAE and L-AA showed a significant increase in the reduced hyaluronic acid and COL1 contents by UVB exposure (Figure 2E,F). Moreover, the mRNA expression of COL1 and hyaluronic acid syntheses related genes (_COLIA_ and _HAS_) were significantly increased by both UAE and L-AA (Figure 2G,H). To elucidate the effects of UAE on collagen degradation, the mRNA expression of the MMPs was quantified using real-time PCR analysis. The UVB-induced mRNA expression of _MMP1_, _MMP9_, and _MMP13_ were significantly reduced by UAE and L-AA (Figure 2I). No significant differences were detected between the UAE- and L-AA treated mice receiving an equal oral dosage.  
Figure 1: Bodyweight changes on the days after UVB irradiation and oral administration. The mice were irradiated to UVB (three times per week) or not for 15 weeks. UAE (100, 200, and 400 mg/kg) or L-AA (100 mg/kg) was orally administrated once a day for 105 days after 1 h of UVB irradiation. All mice were overnight fasted prior to both first administration and sacrifice. The body weights were measured every week. Data are represented as mean \(\pm\) SD (n = 10, significance compared with intact control mice).  
Figure 2: Effects of UAE on UVB-induced wrinkle formation in dorsal back skin. (**A**) Photograph of dorsal back skin (upper), Monochrome image of skin replicas (lower). Scale bars indicate10 mm. Wrinkle  
shadows were generated using an optic light source by a fixed intensity at a 40\({}^{\circ}\) angle. (**B**,**C**) Wrinkle length and depth were measured in skin replicas. (**D**) Water contents in dorsal back skin tissues. Data are presented as a percentage of the total weight of the dorsal back skin tissue (6 mm diameter). (**E**) COL1 and (**F**) hyaluronic acid contents in dorsal back skin tissues. COL1 and hyaluronic acid contents were determined by ELISA assay. Data are presented as a percentage of intact control. (**G**) COL1 synthetic (_COL1A1_ and _COL1A2_), (**H**) hyaluronic acid synthesis (_HAS1_, _HAS2_, and _HAS3_), and (**I**) MMP (_MMP1_, _MMP9_, and _MMP13_) gene expression in dorsal back skin tissues. mRNA expressions levels were quantified using the real-time PCR analysis. Data are expressed relative to intact/\(\beta\)-actin. Dorsal back skin was sampled at 24 h after the last day of administration. Results are presented as mean \(\pm\) SD (n = 10, significant difference vs. intact control; **_p_ < 0.01, vs. UVB-irradiated control mice; **_p_ < 0.01).