Protective effect of taurine on UVB-induced skin aging in hairless mice

Salvianolic acid B protects against UVB-induced skin aging via activation of NRF2

BACKGROUND

Prolonged exposure to sun radiation may result in harmful skin photoaging. Therefore, discovering novel anti-photoaging treatment modalities is critical. An active component isolated from Salvia miltiorrhiza (SM), Salvianolic acid B (Sal-B), is a robust antioxidant and anti-inflammatory agent. This investigation aimed to discover the therapeutic impact and pathways of salvianolic acid B for UVB-induced skin photoaging, an area that remains unexplored.

METHODS

We conducted in vitro experiments on human dermal fibroblasts (HDFs) exposed to UVB radiation, assessing cellular senescence, superoxide dismutase (SOD) activity, cell viability, proliferation, migration, levels of reactive oxygen species (ROS), and mitochondrial health. The potential mechanism of Sal-B was analyzed using RNA sequencing, with further validation through Western blotting, PCR, and nuclear factor erythroid 2-related factor 2 (NRF2) silencing methods. In vivo, a model of skin photoaging induced by UVB in nude mice was employed. The collagen fiber levels were assessed utilizing hematoxylin and eosin (H&E), Masson, and Sirus red staining. Additionally, NRF2 and related gene and protein expression levels were identified utilizing PCR and Western blotting.

RESULTS

Sal-B was found to significantly counteract photoaging in UVB-exposed skin fibroblasts, reducing aging-related decline in fibroblast proliferation and an increase in apoptosis. It was observed that Sal-B aids in protecting mitochondria from excessive ROS production by promoting NRF2 nuclear translocation. NRF2 knockdown experiments established its necessity for Sal-B's anti-photoaging effects. The in vivo studies also verified Sal-B's anti-photoaging efficacy, surpassing that of tretinoin (Retino-A). These outcomes offer novel insights into the contribution of Sal-B in developing clinical treatment modalities for UVB-induced photodamage in skin fibroblasts.

CONCLUSION

In this investigation, we identified the Sal-B protective impact on the senescence of dermal fibroblasts and skin photoaging induced by radiation of UVB. The outcomes suggest Sal-B as a potential modulator of the NRF2 signaling pathway.

Chitosan-taurine nanoparticles cross-linked carboxymethyl chitosan hydrogels facilitate both acute and chronic diabetic wound healing

Wound dressing diligently facilitate healing by fostering hemostasis, immunoregulation, the angiogenesis, and collagen deposition. Our methodology entails fabricating chitosan-taurine nanoparticles (CS-Tau) through an ionic gelation method. The morphology of CS-Tau was observed utilizing Transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Dynamic Light Scattering (DLS). The nanoparticles are subsequently incorporated into carboxymethyl chitosan hydrogels for crosslinking by EDC-NHS, yielding hydrogel dressings (CMCS-CS-Tau) designed to extend the duration of taurine release. In vitro investigations confirmed that these innovative compound dressings displayed superior biodegradation, biocompatibility, cytocompatibility, and non-toxicity, in addition to possessing anti-inflammatory properties, and stimulating the proliferation and mobility of human umbilical vein endothelial cells (HUVECs). Experiments conducted on mice models with full-thickness skin removal demonstrated that CMCS-CS-Tau efficaciously aided in wound healing by spurring angiogenesis, and encouraging collagen deposition. CMCS-CS-Tau can also minimize inflammation and promote collagen deposition in chronic diabetic wound. Hence, CMCS-CS-Tau promotes both acute and chronic diabetic wound healing. Furthermore, the sustained release mechanism of CMCS-CS-Tau on taurine reveals promising potential for extending its clinical utility in relation to various biological effects of taurine.

Taurine deficiency associated with dilated cardiomyopathy and aging

Taurine (2-aminoethanesulfonic acid) is a free amino acid found ubiquitously and abundantly in mammalian tissues. Taurine content in the heart is approximately 20 mM, which is approximately 100 times higher than plasma concentration. The high intracellular concentration of taurine is maintained by the taurine transporter (TauT; Slc6a6). Taurine plays various roles, including the regulation of intracellular ion dynamics, calcium handling, and acting as an antioxidant in the heart. Some species, such as cats and foxes, have low taurine biosynthetic capacity, and dietary taurine deficiency can lead to disorders such as dilated cardiomyopathy and blindness. In humans, the relationship between dietary taurine deficiency and cardiomyopathy is not yet clear, but a genetic mutation related to the taurine transporter has been reported to be associated with dilated cardiomyopathy. On the other hand, many studies have shown an association between dietary taurine intake and age-related diseases. Notably, it has recently been reported that taurine declines with age and is associated with lifespan in worms and mice, as well as healthspan in mice and monkeys. In this review, we summarize the role of dietary and genetic taurine deficiency in the development of cardiomyopathy and aging.

Anti-skin aging effect of sea buckthorn proanthocyanidins in D-galactose-induced aging mice

Oxidative stress in skin cells caused by changes in the external environment is one of the principal causes of skin aging. Sea buckthorn proanthocyanidins (SBPs) have good free radical scavenging ability. We established a senescence model by injecting 500 mg/kg D-galactose into the dorsal necks of mice, and then different doses of SBP (25, 50, and 100 mg/kg) were gavaged to explore the effects of SBP on the skin tissues of senescent mice and elucidate the related mechanism of action. The results reveal that SBP can alleviate the skin aging phenomenon caused by D-galactose-induced aging. It can also enhance the total antioxidant capacity in the body, thereby strengthening the body's antioxidant defense capability. In addition, SBP can effectively improve skin aging by regulating the TGF-β1/Smads pathway and MMPs/TIMP system, increasing the relative content of Col I and tropoelastin, further maintaining the stability of collagen fiber and elastic fiber structure. These results will provide the development and production of the antioxidant function of cosmetics and health products, providing a new train of thought.

Taurine accelerates the synthesis of ceramides and hyaluronic acid in cultured epidermis and dermal fibroblasts

Taurine is a sulfur-containing amino acid derivative that can be found in the majority of mammalian tissues. Taurine is also present in the skin and is involved in maintaining skin homeostasis by exerting osmoregulatory and antioxidant effects. Previous studies have indicated that taurine treatment is effective against age-, ultraviolet- or detergent-induced skin dysfunction. To determine the mechanism responsible for the beneficial actions of taurine in the skin, the present study aimed to evaluate the effects of taurine on epidermal components (ceramides and filaggrin) and on the dermal extracellular matrix, in three-dimensionally (3D) cultured epidermis and dermal fibroblasts, respectively. These cells were cultured in the presence of 3-50 mM taurine, and cells or culture medium were collected for analysis. The effects of taurine on transepidermal water loss (TEWL) in the skin and the expression of inflammatory cytokines, including IL-1α, IL-1β and IL-1 receptor antagonist, were investigated in acetone-treated 3D-cultured epidermis using a Tewameter and reverse transcription-quantitative PCR (RT-qPCR), respectively. The mRNA expression levels of MMP-1 and hyaluronic acid (HA) production were measured in skin dermal fibroblasts using RT-qPCR and ELISA, respectively. Taurine was found to suppress acetone-induced elevation in TEWL in 3D-cultured epidermis. Taurine also stimulated the mRNA expression of ceramide synthase 4 and filaggrin, a major structural protein in the stratum corneum, in 3D-cultured epidermis. In skin dermal fibroblasts, taurine inhibited the IL-1α-stimulated mRNA and protein expression of MMP-1. In addition, taurine treatment increased HA synthase-2 mRNA expression and in turn HA production. Results from the present study suggest that the protective effect of taurine on the skin is associated with the enhancement of epidermal barrier component expression and modulation of dermal extracellular matrix metabolism.

Hemin protects UVB-induced skin damage through inhibiting keratinocytes apoptosis and reducing neutrophil infiltration

Ultraviolet-B (UVB) exposure on the skin triggers apoptosis, oxidative stress and acute inflammatory responses, which eventually increases the risk of various skin disorders. Hemin, an iron-binding porphyrin, has been clinically used for porphyria treatment. However, whether hemin contributes to the skin protection against UVB injury remains to be elucidated. Here, we found that hemin treatment (10 and 20 mg/kg) by intraperitoneal administration could dramatically relieve UVB irradiation-induced skin damage featured by erythema, edema, epidermal hyperplasia and collagen loss in C57BL/6 J mice. Importantly, hemin treatment attenuated UVB irradiation-triggered cell apoptosis in skin epidermis. Consistently, hemin (10, 20 μM) treatment decreased Caspase-3 activation and protected against UVB-induced apoptosis in HaCaT cells. Besides, hemin treatment reduced the infiltration of neutrophils in skin under UVB irradiation, thus restrained neutrophil extracellular traps (NET) formation and myeloperoxidase (MPO) release. We further revealed that hemin inhibited the expression of inflammation associated cytokines and chemokines in UVB-induced HaCaT cells and blocked the chemotaxis of dHL-60 cells to preconditioned media from HaCaT culture upon UVB irradiation. Furthermore, hemin inhibited the excessive maturation and mobilization of bone marrow neutrophils and rectified the proportion of abnormally elevated neutrophils in the blood under UVB irradiation. In conclusion, our study showed that hemin treatment protects against UVB-induced skin damage through inhibiting keratinocytes apoptosis, and suppressing neutrophils infiltration in the skin via externally restraining the keratinocyte attraction and internally regulating bone marrow neutrophil maturation and mobilization, suggesting that hemin is an effective drug candidate for the therapy of UVB damage.

Age-Defying and Photoprotective Potential of Geranium/Calendula Essential Oil Encapsulated Vesicular Cream on Biochemical Parameters against UVB Radiation Induced Skin Aging in Rat

UVB irradiation promotes the production of reactive oxygen species, which can lead to an increase in oxidative stress in the cell and the generation of toxic components, resulting in photoaging. Essential oils (EOs) are well-known in the cosmetics sector for their beneficial effects, as they have a wide range of biological activities. Considering this fact, the current study investigates the photoprotective potential of geranium essential oil (GEO)/calendula essential oil (CEO) encapsulated vesicular cream on the biochemical parameters of the skin of albino rats exposed to UVB radiation. After 30 days of treatment with cream formulations and UVB irradiation, the skin tissue was assayed for several biochemical parameters and histopathology analysis. The results of biochemical study revealed that, in comparison to non-vesicular creams, vesicular cream formulations were able to protect the endogenous skin natural antioxidant system by maintaining superoxide dismutase, catalase, total protein, ascorbic acid, and hydroxyproline levels and by decreasing malondialdehyde levels in the skin after UVB exposure. Changes in various cellular structures along with the change in the epidermis and dermis of the skin after UVB exposure in the treated group were observed by a histopathology of skin tissue and compared to the non-treated group, which revealed the skin damaging effect of UVB radiation and the protective effect of vesicular creams. The results suggest that the GEO/CEO-encapsulated vesicular creams have the potential to protect the skin against harmful UVB radiation by maintaining the natural antioxidant defence mechanism of the skin. In conclusion, this research presents novel herbal cosmetic formulations with improved antioxidant capacity and photoprotective potential that may help to slow down the skin aging process.