The current method for efficient evaluation of antiphotoaging compounds is an in vitro skin culture model using a single ultraviolet A (UVA) irradiation of fibroblasts. However, skin photoaging is caused by repeated exposure to UVA radiation. The objective of this study was to develop an appropriate model for in vitro skin photoaging by comparing the different effects of single (5 J cm ) and repeated exposures (5 J cm × 3 times) of fibroblasts to UVA irradiation. Our results demonstrated that a single and repeated exposure to UVA irradiation had different effects on fibroblasts. In the single UVA-irradiated group, collagen lattice contraction and the protein levels of type I procollagen and matrix metalloproteinase-1 (MMP-1) increased, while the levels of fibronectin and alpha-smooth muscle actin (α-SMA) were unchanged, compared to levels in the non-UVA-irradiated group (control). In contrast, repeated UVA exposure significantly induced G0/G1 cell cycle arrest, reduced collagen lattice contraction and type I procollagen and fibronectin expression, and increased MMP-1 expression. There was no difference in α-SMA expression when comparing repeatedly irradiated and non-UVA-irradiated fibroblasts. Our findings clearly indicate that repeated UVA irradiation of cells induces malfunctions found in photoaged skin and is an appropriate in vitro skin model of photoaging.

Objective The moisturizing and irritation effects of sacha inchi oil were evaluated. Study Design The moisturizing effect on the skin was clinically assessed using a regression study design. Sacha inchi oil or olive oil (benchmark) was applied on the left or right lower leg of the subjects for 14 days followed by application discontinuation for 2 days. The TEWL, skin moisture content and dryness appearance were observed. Methods The fatty acid composition and characteristics of cold‐pressed sacha inchi seed oil were determined. Skin tissues cultured ex vivo were used to assess primary irritation induced by the oil by examining keratin 1 expression and TNF‐α and IL‐1α release from the oil‐applied tissues. Results The sacha inchi oil contained 42.3% linolenic acid and 39.5% linoleic acid. This oil's saponification, iodine, acid and peroxide values were 168.58 ± 1.55 mg KOH/g, 203.00 ± 0.04 g I2/100 g, 1.68 ± 0.03 mg KOH/g, and 1.95 ± 0.26 mEq peroxide/kg, respectively. Compared with nontreated skin tissues, induced secretion of TNF‐α and IL‐1α and disruption of keratin 1 integrity in the stratum corneum layer were not found in the sacha inchi oil‐treated tissues. In a clinical study with 13 volunteers, the improvement in moisture content and skin dryness appearance at the sacha inchi oil‐applied site was comparable with that observed at the olive oil‐applied site. Conclusions The sacha inchi oil was mild to the skin and benefited dry skin.

The physicochemical and biological properties of the blended fibroin/aloe gel film as a wound dressing were investigated to support the wound healing efficacy of the film described in our previous study. In the current study, protein content, molecular weight pattern, and chemical characteristics of the silk fibroin and the aloe gel extracts were analyzed. The two extracts were then dissolved in lactic acid solution and casted to obtain the blended fibroin/aloe gel film. We found that gamma irradiation did not affect any physicochemical properties of the film, i.e., the irradiated and the non-sterilized films had similar physical appearance, surface morphology, mechanical properties, and chemical characteristics. On normal human fibroblast cultures, the film induced non-cytotoxicity and stimulated the expression of vascular epidermal growth factor. The film-treated cells were shown to proliferate by shifting from G 0 /G 1 phase (76.26 ± 0.72%) to S phase (7.19 ± 0.23%) and G 2 /M phase (16.09 ± 0.58%) which are higher than the untreated cells. The film-treated cells provided a completely healed scratch at 36 h after scratch creation, while the created scratch of the untreated cells was not healed, indicating that the biological activity of the film enhanced the proliferation and the migration of fibroblast cells. We speculated that the prepared film might be able to use as wound dressing for the diabetic foot ulcer.

Acne vulgaris is a common chronic inflammatory skin disease. In the present study, we reported the anti-acne vulgaris effect of the Mesua ferrea (M. ferrea) flower extract. The extract was evaluated for three anti-acne-causing bacteria properties including Cutibacterium acnes (C. acnes), Staphylococcus epidermidis (S. epidermidis) and Staphylococcus aureus (S. aureus). The results indicated that the M. ferrea flower extract could be considered as the bactericidal agent against S. epidermidis and S. aureus with MIC values of 0.78 and 6.25 mg mL−1 and MBC values of 1.56 and 12.50 mg mL−1 and the bacteriostatic agent against C. acnes with MIC and MBC values of 3.12 and 25.00 mg mL−1, respectively. The extract at a concentration of 25 µg mL−1 also presented potent anti-inflammatory activity with a significant decrease of nitric oxide (NO) and tumor necrosis factor (TNF)-α productions in RAW 264.7 macrophage cells stimulated by LPS. In addition, the extract showed moderate to weak anti-oxidative capacities against DPPH, ABTS, FRAP and NO assays and also showed weak anti-tyrosinase activity. M. ferrea flower extract may serve as the alternative natural anti-acne formulations.

Skin photoaging is caused by cumulative UVA exposure that leads to dermal matrix alterations associated with impaired fibroblast functions. In this study, we evaluated the effects of repeated UVA irradiation on mechanically stressed fibroblasts which were embedded in 3D tense collagen matrix. By comparison to 2D monolayer culture, we investigated the expressions of alpha-smooth muscle actin (α-SMA) cytoskeleton and α2 subunit of integrin receptors, as well as the collagen metabolism, focusing to MMP-1 and collagen type-I expressions. We found that UVA exposure reduces collagen levels in both culture conditions. However, concerning integrin α2 and α-SMA expression, UVA irradiation had no effect on 2D culture, whereas in tense 3D culture, it had an inhibitory effect. In UVA-irradiated 3D culture, fibroblasts acquired elongated shape and lost their dynamic interaction with collagen fibers through a decrease in integrin α2 and α-SMA. Fibroblast responses to UVA irradiation were different in 2D versus 3D environment, highlighting the importance of collagen environment in the regulation of mechanical activities. The behavior of fibroblast upon mechanical stimulation closely mimics stressed extracellular environment. The model of UVA-irradiated fibroblasts cultured in tense 3D collagen gel illustrated the in vivo situation of both mechanically stressed and photoaged human skin.