Construction of a mouse model for sensitive skin research.

BACKGROUND: Current animal models of sensitive skin do not adequately reflect the objective symptoms or physiological manifestations observed in human sensitive skin. OBJECTIVE: To construct and validate a sensitive skin model in mice. METHODS: Tape stripping (TS) was used to induce partial mechanical disruption of the lipid film and stratum corneum. Subsequently, propylene glycol (PG) was applied to disrupt the lipid structure in the skin barrier, and capsaicin (CS) activate transient receptor potential vanilloid 1 (TRPV1) receptors of keratinocytes to simulate the formation of sensitive skin. Evident itching and tingling sensations, scaly skin, vasodilation, local congestion, increased transepidermal water loss (TEWL), elevated TRPV1 expression, and inflammatory symptoms were subsequently evaluated. RESULTS: TS combined with PG and CS application resulted in skin flakes; skin barrier disruption; vascular dilation; increased itching, stinging, and inflammation; TRPV1 upregulation in the epidermis; and a significant increase in lactic acid-induced itching and stinging. CONCLUSION: Using a combination of TS and PG, and CS application, a mouse model of sensitive skin was successfully established involving various skin phenotypes and physiological manifestations, including skin flakes, vasodilation, increased blood flow and TEWL, itching and stinging sensations, inflammation, and elevated TRPV1 expression.

Emu oil alleviates atopic dermatitis-like responses by inhibiting Cdc42 signaling of keratinocyte.

Emu oil is the oil extracted from the body fat of the Australian bird emu. Although previous studies have reported that emu oil has anti-inflammatory effects, the effect and mechanism of emu oil on the treatment of atopic dermatitis have not been reported. Here, 2, 4-dinitrofluorobenzene was used to induce atopic dermatitis-like appearance on the back skin of C57BL/6 mice. And then, the effect of emu oil in the atopic dermatitis treatment was evaluated. We found that emu oil reduced the transdermal water loss in the atopic dermatitis model. Additionally, the epidermal thickness treated with emu oil was significantly thinner. The number of mast cells and inflammatory cells were significantly decreased. The thymic stromal lymphopoietin (TSLP), which is secreted by keratinocyte, was decreased significantly after treatment. Moreover, the serum levels of cytokines TSLP, interleukin-4, interleukin-13, and immunoglobulin (Ig) E were decreased after emu oil treatment. Surprisingly, we found that the high level of Cdc42 expression in the atopic dermatitis, which was decreased after emu oil treatment. To detect the role of Cdc42 in atopic dermatitis, we constructed atopic dermatitis model in mice with sustained activation of Cdc42 signaling. Furthermore, we have confirmed that emu oil demonstrates anti-inflammatory effects in atopic dermatitis by inhibiting the expression of Cdc42 signaling in keratinocytes. In conclusion, we discovered a new role of Cdc42 in the development of atopic dermatitis, which mediated the therapeutic effect of emu oil on atopic dermatitis.

A Comparative Study of Skin Changes in Different Species of Mice in Chronic Photoaging Models.

This study aimed to design a novel mouse model of chronic photoaging. We used three different species of mice (C57BL/6J, ICR, and KM) to create a chronic photoaging model of the skin. The irradiation time was gradually increased for 40 consecutive days. The skins of the mice were removed on day 41 and subjected to staining to observe them for morphological changes. Immunohistochemistry was used to detect tumor necrosis factor-α (TNF-α) and p53 expression; superoxide dismutase (SOD) and malondialdehyde (MDA) were measured as well. Compared with C57BL/J mice, which showed hyperpigmentation, the irradiated skin of ICR and KM mice showed more obvious skin thickening and photoaging changes of the collagen and elastic fibers. KM mice had higher levels of inflammation, oxidative stress, and senescent cells. Compared with the 5-month-old KM mice, the photoaging changes of the 9-month-old KM mice were more pronounced, the SOD values were lower, and the MDA values were higher. In summary, KM mice have higher levels of abnormal elastic fibers, inflammation, cellular senescence, and oxidative stress than ICR mice, and are more suitable for studies related to chronic skin photoaging. C57BL/6J mice were found to be suitable for studies related to skin pigmentation due to photoaging.

Activin B-activated Cdc42 signaling plays a key role in regulating adipose-derived mesenchymal stem cells-mediated skin wound healing.

BACKGROUND: In our previous study, activin B in combination with ADSCs enhances skin wound healing. However, the underlying molecular mechanisms are not well studied. Cdc42 is recognized to play a critical role in the regulation of stem cells. METHODS: Pull-down assay was performed to investigate the activity of Cdc42. The dominant-negative mutant of Cdc42 (Cdc42N17) was used to explore the role of Cdc42 in activin B-induced ADSCs migration, proliferation, and secretion in vitro. Cdc42N17-transfected ADSCs were injected into a full-thickness excisional wound model to explore their efficiency in wound healing in vivo. The wound healing efficacy was evaluated by the wound closure rates and histological examination. The neovascularization and wound contraction were detected by immunohistochemistry staining of CD31 and α-SMA. Finally, the underlying mechanisms were explored by RNA sequencing. RESULTS: Cdc42N17 inhibited ADSCs migration, proliferation, and secretion induced by activin B. Furthermore, Cdc42N17-transfected ADSCs inhibited the wound closure rate and suppressed the expression of CD31 and α-SMA induced by activin B in vivo. The RNA sequencing showed that the differentially expressed genes in Cdc42N17-transfected ADSCs versus ADSCs were associated with cell migration, proliferation, and adhesion. Further study revealed that the Cdc42-Erk-Srf pathway was required for activin B-induced proliferation in ADSCs. CONCLUSIONS: Our study indicates that Cdc42 plays a crucial role in ADSCs-mediated skin wound healing induced by activin B.