Increase In Skin Thickness Research Articles

Short-chain fatty acids ameliorate imiquimod-induced skin thickening and IL-17 levels and alter gut microbiota in mice: a metagenomic association analysis

Short-chain fatty acids (SCFAs) have been proposed to have anti-inflammatory effects and improve immune homeostasis. We aimed to examine the effects of SCFAs on skin phenotype, systemic inflammation, and gut microbiota in mice with psoriasis-like inflammation. Imiquimod (IMQ)-treated C57BL/6 mice served as the study model. We conducted a metagenomic association study of IMQ-mice treated with SCFAs or anti-IL-17 antibody using whole-genome shotgun sequencing. The associations among SCFA supplements, skin thickness, circulating inflammatory profiles, and fecal microbiota profiles were investigated. The microbiome study was performed using pipelines for phylogenetic analysis, functional gene analysis, and pathway analysis. In IMQ-treated mice, there were increases in skin thickness and splenic weight, as well as unique fecal microbial profiles. SCFAs ameliorated IMQ-induced skin thickening, splenic weight gain, and serum IL-17F levels, with results that were comparable with those receiving anti-IL-17 treatment. IMQ-treated mice receiving SCFAs had greater microbial diversity than mice treated with IMQ alone. SCFAs and anti-IL17 treatment were associated with alteration of gut microbiota, with increased prevalences of Oscillospiraceae and Lachnopiraceae and decreased prevalences of Muribaculaceae and Bacteroides, which have been predicted to be associated with increased glycan degradation, phenylalanine metabolism, and xylene degradation. SCFAs may mitigate IMQ-induced skin thickening and IL-17F levels and alter fecal microbiota profiles in IMQ-treated mice.

Performance of polyvinyl chloride-based E-glass reinforced isophthalic and orthophthalic polyester sandwich composites: A comparative study

This study investigates the performance of sandwich composites composed of polyvinyl chloride cores reinforced with E-glass fibers and bonded with isophthalic and orthophthalic polyester skins. The aim is to comparatively assess the mechanical and morphological characteristics of these composite structures. The comparative analysis also included variations in the skin thickness of the sandwich composite. Mechanical tests such as compressive, impact, and hardness were carried out. Moreover, fracture tests specifically focusing on single-edge notched beam fracture (mode I) were conducted under different temperature conditions, low (−10 °C), ambient (25 °C), and high (100 °C) temperatures. Comparative analysis of the mechanical properties indicated that the isophthalic-based sandwich composites exhibited superior mechanical characteristics when compared to their orthophthalic counterparts. Fracture properties of both types of sandwich composites demonstrated higher values at lower temperatures, followed by room temperature, and then high temperatures. In both types of sandwich composites, using two layers of E-glass on both sides of the polyvinyl chloride foam resulted in superior properties. This improvement can be attributed to the increased skin thickness. The interfacial properties were identified using Fourier transform infrared spectroscopy and scanning electron microscopy, revealing distinct spectroscopic features such as CH-stretching, C–O–C, CH bend, CN stretching, and NH stretching. Examination of the fractured surfaces through scanning electron microscopy revealed distinct features such as crushed fiber, fiber pull-out, honeycomb, riverline patterns, matrix-fiber delamination, and debonding, providing valuable insights into the composite's structural integrity.

Deletion of adipocyte Sine Oculis Homeobox Homolog 1 prevents lipolysis and attenuates skin fibrosis.

Dermal fibrosis is a cardinal feature of systemic sclerosis (SSc) for which there are limited treatment strategies. This is in part due to our fragmented understanding of how dermal white adipose tissue (DWAT) contributes to skin fibrosis. We identified elevated sine oculis homeobox homolog 1 (SIX1) expression in SSc skin samples from the GENISOS and PRESS cohorts, the expression of which correlated with adipose-associated genes and molecular pathways. SIX1 localization studies identified increased signals in the DWAT area in SSc and in experimental models of skin fibrosis. Global and adipocyte specific Six1 deletion abrogated end-stage fibrotic gene expression and dermal adipocyte shrinkage induced by SQ bleomycin treatment. Further studies revealed a link between elevated SIX1 and increased expression of SERPINE1 and its protein PAI-1 which are known pro-fibrotic mediators. However, SIX1 deletion did not appear to affect cellular trans differentiation. Taken together these results point at SIX1 as a potential target for dermal fibrosis in SSc.

Oral Exposure to Low Concentration of Fumonisin B2, but Not Fumonisin B1, Significantly Exacerbates the Pathophysiology of Imiquimod-Induced Psoriasis in Mice.

This study aimed to determine whether oral fumonisin exposure contributes to the development of psoriasis. Oral administration of fumonisin B1 (FB1, 0.1 mg/kg) or fumonisin B2 (FB2, 0.1 mg/kg) was conducted for 10 days, in addition to the induction of psoriatic symptoms through topical application of 5% imiquimod cream from day 6 to day 10 (5 days) in female BALB/c mice. The results demonstrated that oral administration of FB2 significantly exacerbated psoriatic symptoms, including skin thickness, itching behavior, transepidermal water loss, immune cell infiltration in the dermis, and proinflammatory cytokine production. However, no changes were observed following exposure to FB1. Our results confirm that oral exposure to FB2 adversely affects the pathogenesis of psoriasis by increasing skin thickness and impairing barrier function.

Itch and Pain Behaviors in Irritant Contact Dermatitis Produced by Sodium Lauryl Sulfate in Mice.

Irritant contact dermatitis (ICD) is a nonspecific skin inflammation caused by irritants, leading to itch and pain. We tested whether differential responses to histamine-dependent and -independent pruritogens can be evoked in ICD induced by sodium lauryl sulfate (SLS). An ICD mouse model was established with 5% SLS in acetone versus a vehicle topically applied for 24 h to the cheek. Site-directed itch- and pain-like behaviors, occurring spontaneously and in response to mechanical, thermal, and chemical stimuli (histamine, ß-alanine, BAM8-22, and bradykinin) applied to the cheek, were recorded before (day 0) and after irritant removal (days 1, 2, 3, and 4). Skin inflammation was assessed through visual scoring, ultrasound, and measurements of skin thickness. SLS-treated mice exhibited hyperalgesia-like behavior in response to mechanical and heat stimuli on day 1 compared to the controls. SLS mice exhibited more spontaneous wipes (pain) but not scratching bouts (itch) on day 1. Pruritogen injections caused more scratching but not wiping in SLS-treated mice compared to the controls. Only bradykinin increased wiping behavior compared to saline. SLS-treated mice developed noticeable erythema, scaling, and increased skin thickness on days 1 and 2. SLS induced cutaneous inflammation and behavioral signs of spontaneous pain and itching, hyperalgesia to mechanical and heat stimuli and a chemical algogen, and enhanced itch response to pruritogens. These sensory reactions preceded the inflammation peak and lasted up to two days.

Assessment of Skin by High Frequency Musculoskeletal Ultrasound in Egyptian Patients with Systemic Sclerosis

Abstract Background Fibrotic involvement of the skin is a cardinal feature of systemic sclerosis (SSc). The extent of skin involvement is associated with internal organ involvement with severe disease course and poor prognosis. SSc skin involvement is characterized by three phases in temporal sequence: edematous, fibrotic, and atrophic. A palpation-based semi- quantitative score, the modified Rodnan skin score (mRSS) is widely used for the assessment of skin involvement. It is a quick, noninvasive clinical assessment that correlates with histological grading of skin fibrosis. However, it lacks the sensitivity to differentiate between clinically indistinguishable pathological phases such as inflammatory edema vs. established fibrosis. More objective approaches to measure skin involvement imaging have been developed in the past decades.In our study, we review the use of ultrasound for the assessment of early changes in skin thickness and echogenicity in patients with SSc, focusing. mainly on high frequency ultrasound. Aim of the Work to evaluate the role of high frequency ultrasound (HFUS) of skin in assessment of early changes in skin thickness and echogenicity in patients with SSc. Patients and Methods Our study is a cross-sectional, observational study involving homogenous groups consisting of 23 SSc patients and 21 healthy age and sex matched controls. Patients who fulfilled the 2013 ACR/EULAR Classification Criteria for SSc. Results DT was evaluated by both mRSS and HFUS at 5 skin areas in both patients and control. We found statistically significant difference between the two studied groups as regards in area 1 longitudinal (P = 0.017) and area 1 in transverse (P = 0.038), tendency to significance in area 2 (P = 0.054). Subclinical dermal involvement was detected by HFUS even in the skin areas in patients who had a normal local MRSS ( These areas were not planned to be assessed by high frequency ultrasound but added to the five areas to be assessed to evaluate for ultrasound detected subclinical involvement of skin in SSc patients ). In particular, DT was highly significantly greater in patients with area with Rodnan zero score at dorsum of hand than in healthy subjects (longitudinal and transverse) (P < 0.001, 0.005 ) respectively. Similar changes at the level of echogenicity occurred in determination of the stage of the disease, with increased skin thickness and decreased echogenicity occurring early and during skin disease activity due to edema; and decrease skin thickness and increased echogenicity occurring late with skin atrophy Conclusion that high frequency ultrasound is a useful tool in assessment of skin pathologic changes (even subclinical changes) in terms of thickness and echogenicity in patients with SSc both at disease onset and during follow up of response to therapy and disease stage. Moreover, it could be a useful screening tool with definite cutoff values at certain areas that differentiate normal from pathologic skin thickness.

Skin thickness effects on failure mechanisms in foam infilled composite sandwich structures

Sandwich structures are often prone to catastrophic failure due to premature separation between the core and skin layers. Geometric parameters, such as the thickness of the skin and core, along with the materials used in their manufacturing, directly influence the resistance to separation between the skin and core. This study explores how variations in skin thickness affect both failure modes and maximum load capacity in sandwich structures, utilizing both experimental testing and numerical simulations. Specimens were categorized as intact and pre-debonded samples. Each specimen featured four different skin thicknesses (3, 6, 8, and 10 layers of composite laminated skins, with corresponding thicknesses of 0.68, 1.33, 1.73, and 2.1 mm respectively). The specimens incorporated a foam-filled square corrugated core and underwent 3-point bending tests. Results revealed a significant shift in the failure mode: initially observed as upper skin fracture (V-shaped failure), it transitioned to separation between skins and cores with increased skin thickness, particularly in the presence of pre-debonding. Notably, the predominant failure mode did not involve separation between the skin and core in specimens without a pre-existing crack. Furthermore, numerical simulations effectively demonstrated the accurate capture of failure modes and loads using the Hashin and cohesive zone model (CZM).

Prinsepia utilis Royle polysaccharides promote skin barrier repair through the Claudin family.

Plant polysaccharides have various biological activities. However, few studies have been conducted on the skin barrier of Prinsepia utilis Royle polysaccharide extract (PURP). The proportions of polysaccharides, monosaccharides and proteins were determined by extracting polysaccharides from fruit meal using water. The healing rate was measured by cell scratch assays. SDS-damaged reconstructed human epidermal models, an acetone-ether-induced mouse model and an IL-4-induced cellular inflammation model were used to detect the effects of polysaccharides on the phenotype, HA, TEWL, and TEER, with further characterizations performed using QRT-PCR, Western blotting, immunofluorescence (IF) assays. PURP contained 35.73% polysaccharides and 11.1% proteins. PURP promoted cell migration and increased skin thickness in a reconstructed human epidermis model. The TEWL significantly decreased, and the HA content significantly increased. PURP significantly increased the TEER and decreased the permeability of the SDS-damaged reconstructed human epidermis model. Claudin-3, Claudin-4, and Claudin-5 were significantly upregulated. IF and Western blot analysis revealed that the Claudin-4 level significantly increased after treatment with PURP. Claudin-1, Claudin-3, Claudin-4, and Claudin-5 gene expression and IF and immunohistochemical staining were significantly increased in mice treated with acetone-ether. PURP promoted the expression of Claudin-1, Claudin-3, Claudin-4, and Claudin-5 after treatment with 100ng/mL IL-4. PURP also downregulated the expression of NO, IL6, TNFα and NFκB in Raw 264.7 cells and in a mouse model. We hypothesize that PURP may repair the skin barrier by promoting the expression of the claudin family and can assist in skin therapy.

Monotropein mitigates atopic dermatitis-like skin inflammation through JAK/STAT signaling pathway inhibition

Atopic dermatitis (AD) is a globally increasing chronic inflammatory skin disease with limited and potentially side-effect-prone treatment options. Monotropein is the predominant iridoid glycoside in Morinda officinalis How roots, which has previously shown promise in alleviating AD symptoms. This study aimed to systematically investigate the pharmacological effects of monotropein on AD using a 2, 4-dinitrochlorobenzene (DNCB)/Dermatophagoides farinae extract (DFE)-induced AD mice and tumor necrosis factor (TNF)-α/interferon (IFN)-γ-stimulated keratinocytes. Oral administration of monotropein demonstrated a significant reduction in AD phenotypes, including scaling, erythema, and increased skin thickness in AD-induced mice. Histological analysis revealed a marked decrease in immune cell infiltration in skin lesions. Additionally, monotropein effectively downregulated inflammatory markers, encompassing pro-inflammatory cytokines, T helper (Th)1 and Th2 cytokines, and pro-inflammatory chemokines in skin tissues. Notably, monotropein also led to a considerable decrease in serum immunoglobulin (Ig)E and IgG2a levels. At a mechanistic level, monotropein exerted its anti-inflammatory effects by suppressing the phosphorylation of Janus kinase / signal transducer and activator of transcription proteins in both skin tissues of AD-induced mice and TNF-α/IFN-γ-stimulated keratinocytes. In conclusion, monotropein exhibited a pronounced alleviation of AD symptoms in the experimental models used. These findings underscore the potential application of monotropein as a therapeutic agent in the context of AD, providing a scientific basis for further exploration and development.

Lapatinib prevents and ameliorates dermal fibrosis in bleomycin induced experimental scleroderma model

Background: Scleroderma is a connective tissue disease characterized by endothelial damage and diffuse interstitial fibrosis. Lapatinib, a tyrosine kinase inhibitor, is a 4-anilinoquinol derivative. It inhibits many important signalling pathways including MAPK and PI3K. As a result, it affects cell cycle progression, apoptosis, angiogenesis and cell adhesion. Materials and Methods: Mice with an average age of 6 weeks and a weight of 20-25 g were divided into 6 equal groups (n=10 in each group). Mice in the control group (group A and group D), which were not treated with bleomycin (BLM), received sc phosphate buffered saline (PBS) daily. BLM was dissolved in FTS and administered to mice in groups B and C for 3 weeks, and to mice in groups E and F at a dose of sc 100 L (100 g) daily for 6 weeks. Mice in groups A, B and C were sacrificed at the end of week 3; mice in groups D, E and F were sacrificed at the end of week 6 and tissue samples were collected for further analysis. The mRNA expressions of TGF-β1 and fibronectin-1 were determined by RT-PCR. Results: Repeated subcutaneous administration of BLM caused dermal inflammatory cell infiltration, increased skin thickness and dermal fibrosis at early and late stages. TGF-β1 and fibronectin-1 mRNA expressions were also evidently increased. In both prophylactic and therapeutic applications of lapatinib, TGF-β1 and fibronectin-1mRNA expressions decreased markedly. In addition, histopathological dermal necro- inflammation and fibrosis were reduced. Conclusions: Lapatinib may exert anti-fibrotic effects in BLM-induced dermal fibrosis model. Studies show that lapatinib is a potential therapeutic agent, but it needs to be confirmed with in vivo studies.

Assessing the impact of various tuberculin PPD brands on bovine tuberculosis diagnosis

Although several brands of tuberculin purified protein derivatives (PPDs) are available for diagnosing bovine tuberculosis (bTB), comparative studies to determine their diagnostic accuracy are infrequent. In Ecuador we compared two different PPD brands for bTB diagnosis using skin testing and measuring skin thickness increase. Additionally, we evaluated four PPD brands, including those used for skin testing, in the Bovine Tuberculosis Interferon Gamma Test (IFN-γ test) measuring IFN-γ induction in whole blood. The study included 17 naturally tuberculosis-infected PPD and IFN-γ test positive bovines. Both the field and laboratory results showed significant differences in classifying the 17 bovines as bTB positive or negative. We hypothesize that several factors, such as the genetic background of the cows, sensitization to environmental mycobacteria, M. bovis strains involved in the bTB infection, and the manufacturing procedures of the PPDs, could have influenced the immune reaction toward the different tuberculin PPD brands. Our study emphasizes the necessity for comparative studies aimed at determining the diagnostic accuracy of PPD brands for bTB diagnosis as well as the development of standardized methods for PPD production and potency determination.

Preventive effect of human umbilical cord mesenchymal stem cells on skin aging in rats

The irreversibility of aging makes anti-aging become an important research direction in the field of medical research. As the most direct manifestation of human aging, skin aging has been paid more and more attention. Stem cells have been used as a basis for anti-aging studies in skin, of which adipose-derived mesenchymal stem cells are more commonly used. In this study, human umbilical cord mesenchymal stem cells were used, and human umbilical cord mesenchymal stem cells were intervened while making a skin aging model, which was planned to reduce the process of preventing skin aging in the study method. At the end of the experiment, rat skin and serum were taken for relevant data detection. The results showed that the contents of EGF and VEGF in serum and skin tissue of rats increased and the content of MDA decreased after the application of human umbilical cord mesenchymal stem cells. At the same time, hUCMSC intervention increased skin thickness, increased dermal vessels, increased type I collagen type III collagen mRNA expression, and decreased MMP-1 content in rats. The results showed that hUCMSC could prevent skin aging in rats.

Fucosylation deficiency enhances imiquimod-induced psoriasis-like skin inflammation by promoting CXCL1 expression

Psoriasis is a multifaceted chronic inflammatory skin disease; however, its underlying molecular mechanisms remain unclear. In this study, we explored the role of fucosylation in psoriasis using an imiquimod-induced psoriasis-like mouse model. ABH antigen and fucosyltransferase 1 (Fut1) expression was reduced in the granular layer of lesional skin of patients with psoriasis. In particular, the blood group H antigen type 2 (H2 antigen)—a precursor of blood group A and B antigens—and FUT1 were highly expressed throughout the spinous layer in both patients with psoriasis and the skin of imiquimod-treated mice. Upon the application of imiquimod, Fut1-deficient mice, which lacked the H2 antigen, exhibited higher clinical scores based on erythema, induration, and scaling than those of wild-type mice. Imiquimod-treated Fut1-deficient mice displayed increased skin thickness, trans-epidermal water loss, and Gr-1+ cell infiltration compared with wild-type mice. Notably, the levels of CXCL1 protein and mRNA were significantly higher in Fut1-deficient mice than those in wild-type mice; however, there were no significant differences in other psoriasis-related markers, such as IL-1β, IL-6, IL-17A, and IL-23. Fut1-deficient primary keratinocytes treated with IL-17A also showed a significant increase in both mRNA and protein levels of CXCL1 compared with IL-17A-treated wild-type primary keratinocytes. Further mechanistic studies revealed that this increased Cxcl1 mRNA in Fut1-deficient keratinocytes was caused by enhanced Cxcl1 mRNA stabilization. In summary, our findings indicated that fucosylation, which is essential for ABH antigen synthesis in humans, plays a protective role in psoriasis-like skin inflammation and is a potential therapeutic target for psoriasis.

Anti-Inflammatory Artificial Extracellular Vesicles with Notable Inhibition of Particulate Matter-Induced Skin Inflammation and Barrier Function Impairment.

Particulate matter (PM) exposure disrupts the skin barrier, causing cutaneous inflammation that may eventually contribute to the development of various skin diseases. Herein, we introduce anti-inflammatory artificial extracellular vesicles (AEVs) fabricated through cell extrusion using the biosurfactant PEGylated mannosylerythritol lipid (P-MEL), hereafter named AEVP-MEL. The P-MEL has anti-inflammatory abilities with demonstrated efficacy in inhibiting the secretion of pro-inflammatory mediators. Mechanistically, AEVP-MEL enhanced anti-inflammatory response by inhibiting the mitogen-activated protein kinase (MAPK) pathway and decreasing the release of inflammatory mediators such as reactive oxygen species (ROS), cyclooxygenase-2 (COX-2), and pro-inflammatory cytokines in human keratinocytes. Moreover, AEVP-MEL promoted increased expression levels of skin barrier proteins (e.g., involucrin, IVL) and water-proteins (e.g., aquaporin 3, AQP3). In vivo studies revealed that repeated PM exposure to intact skin resulted in cutaneous inflammatory responses, including increased skin thickness (hyperkeratosis) and mast cell infiltration. Importantly, our data showed that the AEVP-MEL treatment significantly restored immune homeostasis in the skin affected by PM-induced inflammation and enhanced the intrinsic skin barrier function. This study highlights the potential of the AEVP-MEL in promoting skin health against PM exposure and its promising implications for the prevention and treatment of PM-related skin disorders.

Simvastatin Attenuates Areca Nut Extract-Induced Subdermal Fibrosis in Mice by Targeting TGF-β Signaling Pathways.

Oral submucous fibrosis (OSMF) is a chronic inflammatory disease and a potentially malignant oral disorder, characterized by fibrosis of the oral mucosa. TGF-β signaling pathways have been implicated in the development of OSMF, with areca nut extract (ANE) contributing to the disease progression. Simvastatin, a statin drug, has demonstrated anti-fibrotic properties in various fibrotic conditions. However, its therapeutic potential in treating OSMF remains unclear. In this study, 8-week-old male BALB/c mice were randomly divided into three groups based on different time points. Each mouse was then treated with four different drug formulations. Post-treatment, specimens were collected for histopathological examination and staining to assess skin thickness, fibrosis, and collagen deposition. ANE treatment alone significantly increased skin thickness and collagen deposition compared to the control group after the 4-week time point. The combined administration of ANE and simvastatin, resulted in a notable reduction in skin thickness and collagen deposition. Western blot analysis revealed that simvastatin effectively suppressed the expression of fibrosis-related proteins, including CTGF, and α-SMA, in ANE-induced subdermal fibrosis. These results suggest that simvastatin has potential therapeutic effects on ANE-induced subdermal fibrosis, providing a foundation for future studies and possible clinical applications.

Thanatophoric Dysplasia – Rare Fatal Skeletal Dysplasia Detected on Prenatal Ultrasound

Abstract Skeletal dysplasias form an assorted cluster of bone dysplasias that result in atypical and aberrant skeletal size and shape. The case discussed here was diagnosed as thanatophoric dysplasia during the second-trimester ultrasound examination and the medical termination of pregnancy was subsequently done. The fetus had shortening of the limbs (micromelia) with long bones (shaped like a telephone receiver), a small conical thorax, a protuberant abdomen, increased skin thickness with a cloverleaf skull, and macrocephaly. The relevant details and review of literature pertinent to the case are hereby discussed.

Carboxytherapy on the treatment of managing cellulite and striae distensae: A systematic review

The use of carboxytherapy has shown excellent results in the treatment of various aesthetic conditions. The aim of this study was to investigate the effects of carboxytherapy on cellulite and striae distensae (SD). Therefore, a systematic literature review was accomplished on two databases, Medline via PubMed and Scopus, from July to August 2021. Studies that evaluated the effect of carboxytherapy on SD and cellulite were included, eight articles of all of them and that treated 299 people were included in this systematic review and the most studies classified as having low level of methodological quality. There was no consensus regarding the parameters used, but in most studies and applications were performed at a depth of 10 mm with a flow ranging from 50 to 150 mL / min. The results this intervention produced an improvement in skin aspects, with better texture, decreased severity of cellulite and SD, improved patient satisfaction, increased skin thickness, decreased edema and increased inflammatory infiltrate the number of collagen fibers. Some side effects were observed, such as transient erythema and post-inflammatory hyperpigmentation, leading to discomfort. However, all these adverse effects are transient, and patients can return to normal activities with the use of photoprotection. This review demonstrates the stimulatory effect of carboxytherapy on the symptomatology of patients with cellulite and SD.

Efficacy of tissue fibroplasia mesotherapy in reducing signs of skin ageing

Tissue fibroplasia, the combination of a biorevitalising mechanism with a biostimulant in a single mesotherapy preparation, is a relatively new group of injectable products. The study aimed to evaluate the effect of preparation with hyaluronic acid and sodium succinate on skin improvement in women with dry skin and clear signs of ageing. It showed a statistically significant decrease in skin echogenicity compared to the original state, an increase in skin thickness and a shallowing of individual wrinkles. Mesotherapy using the mechanism of tissue fibroplasia improves parameters of ageing skin, such as hydration level, thickness of the dermis, visibility of wrinkles, erythema, and skin discolouration.

The Effect of γ-Aminobutyric Acid Intake on UVB- Induced Skin Damage in Hairless Mice.

The skin, the largest organ in the body, undergoes age-related changes influenced by both intrinsic and extrinsic factors. The primary external factor is photoaging which causes hyperpigmentation, uneven skin surface, deep wrinkles, and markedly enlarged capillaries. In the human dermis, it decreases fibroblast function, resulting in a lack of collagen structure and also decreases keratinocyte function, which compromises the strength of the protective barrier. In this study, we found that treatment with γ-aminobutyric acid (GABA) had no toxicity to skin fibroblasts and GABA enhanced their migration ability, which can accelerate skin wound healing. UVB radiation was found to significantly induce the production of matrix metalloproteinase 1 (MMP-1), but treatment with GABA resulted in the inhibition of MMP-1 production. We also investigated the enhancement of filaggrin and aquaporin 3 in keratinocytes after treatment with GABA, showing that GABA can effectively improve skin moisturization. In vivo experiments showed that oral administration of GABA significantly improved skin wrinkles and epidermal thickness. After the intake of GABA, there was a significant decrease observed in the increase of skin thickness measured by calipers and erythema. Additionally, the decrease in skin moisture and elasticity in hairless mice exposed to UVB radiation was also significantly restored. Overall, this study demonstrates the potential of GABA as functional food material for improving skin aging and moisturizing.

Lacticaseibacillus paracasei K71 Alleviates UVB-Induced Skin Barrier Dysfunction by Attenuating Inflammation via Increased IL-10 Production in Mice.

Ultraviolet B (UVB) radiation causes skin barrier dysfunction, leading to decreased water-holding capacity, impaired epidermal barrier function, and increased skin thickness. This study investigates the protective effects of oral administration of Lacticaseibacillus paracasei K71 against skin barrier dysfunction in UVB-irradiated mice. Mice are fed diets with or without K71 and irradiated with UVB three times a week for 12 weeks. Oral administration of K71 suppresses UVB-induced decrease in stratum corneum water content, mitigates the increase of transepidermal water loss, and decreases epidermal thickness of the dorsal skin. Treatment with K71 reverses the upregulation of inflammatory cytokines and the activation of nuclear factor-κB induced by UVB irradiation and upregulates the expression of anti-inflammatory IL-10 in the dorsal skin. Notable upregulation of IL-10 is observed in the spleens of K71-treated mice. K71 treatment enhances IL-10 production in J774.1 macrophages; however, this enhancement is diminished by inhibiting K71 phagocytosis and TLR3. Furthermore, transfection using K71 RNAs significantly increases IL-10 production. These results indicate that K71 may alleviate UVB-induced skin barrier dysfunction by attenuating inflammation via increasing IL-10 production and that K71 RNAs may induce IL-10 production in macrophages. Therefore, K71 may be beneficial for preventing skin barrier dysfunction.