Abstract
Our previous study showed that hydrangenol isolated from Hydrangea serrata leaves exerts antiphotoaging activity in vitro. In this study, we determined its antiphotoaging effect in UVB-irradiated HR-1 hairless mice. We evaluated wrinkle formation, skin thickness, histological characteristics, and mRNA and protein expression using qRT-PCR and Western blot analysis in dorsal skins. Hydrangenol mitigated wrinkle formation, dorsal thickness, dehydration, and collagen degradation. Hydrangenol increased the expression of involucrin, filaggrin, and aquaporin-3 (AQP3) as well as hyaluronic acid (HA) production via hyaluronidase (HYAL)-1/-2 downregulation. Consistent with the recovery of collagen composition, the expression of Pro-COL1A1 was increased by hydrangenol. Matrix metalloproteinase (MMP)-1/-3, cyclooxygenase-2 (COX-2), and interleukin-6 (IL-6) expression was reduced by hydrangenol. Hydrangenol attenuated the phosphorylation of mitogen-activated protein kinases (MAPKs) including ERK and p38, activator protein 1 (AP-1) subunit, and signal transduction and activation of transcription 1 (STAT1). Hydrangenol upregulated the expression of nuclear factor-E2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), NAD(P)H quinone dehydrogenase 1 (NQO-1), glutamate cysteine ligase modifier subunit (GCLM), and glutamate cysteine ligase catalysis subunit (GCLC). Taken together, our data suggest that hydrangenol can prevent wrinkle formation by reducing MMP and inflammatory cytokine levels and increasing the expression of moisturizing factors and antioxidant genes.
Highlights
The human skin protects the body from mechanical damage, penetration of fungi and radiation, and reduces moisture loss, serving as an important barrier to maintaining homeostasis constancy
Skin replicas were prepared from the dorsal skin layer of the HR-1 hairless mice and the severity of skin wrinkles was quantified by assessing wrinkle parameters including total wrinkle area, percentage of wrinkle area, mean length/depth of the wrinkle, and the maximum wrinkle depth
We found that following 7 weeks of oral hydrangenol (5, 10, 20, or 40 mg/kg) administration, these Ultraviolet B (UVB)-induced wrinkle parameters were reduced in a dose-dependent manner (Figure 2B–F)
Summary
The human skin protects the body from mechanical damage, penetration of fungi and radiation, and reduces moisture loss, serving as an important barrier to maintaining homeostasis constancy. Skin aging is categorized into extrinsic and intrinsic aging. Extrinsic aging (photoaging) is mainly caused by ultraviolet (UV) exposure and is characterized by degradation of skin structure and increase in thickness, sagging, roughness, coarse wrinkle formation, and dehydration [1]. Involucrin and filaggrin are associated with skin barrier function. Involucrin is a constituent of the cornified envelope (CE), which is a key component of the SC, and filaggrin makes up the SC and increases the levels of natural moisturizing factors (NMFs), strengthening the skin barrier by maintaining moisture [3,4]. Ultraviolet B (UVB) irradiation destroys skin barrier function by affecting involucrin and filaggrin, thereby increasing transepidermal water loss (TEWL), resulting in the disruption of the SC integrity [5,6,7]
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