Protective effects of Paeonia suffruticosa callus extract in skin through anti-inflammation and repair UVB-induced damage

OBJECTIVE

The study investigated effects of peony callus extracts (PCE) on the protective efficacy against Ultraviolet B (UVB)-induced photoageing, using in vitro and in vivo studies. The research focused on PCE's ability to protect against inflammatory factors, DNA damage and accumulation of senescent cells, along with the evaluation of the extract's potential anti-photoageing benefits to skin.

METHODS

Human keratinocyte cell line (HaCaT cells), mast cells and fibroblasts were used to evaluate the role of PCE in anti-photoageing. The expression of genes of interleukin-1α (IL-1α), IL-6 and transient receptor potential vanilloid 1 (TRPV1) were tested in HaCaT cells. The histamine contents in mast cells were tested to evaluate the effect of PCE on soothing skin. Additionally, the repairment of PCE on DNA damage stimulated by UVB using comet assay was evaluated. In fibroblasts, the gene expression of matrix metalloproteinases (MMPs) and the activity of β-galactosidase were tested. In vivo test, 13 healthy volunteers were enrolled to apply a formula with 1% PCE to assess the variation in inner skin collagen contents.

RESULTS

The callus from an ancient and rare variety of tree peony (Paeoniaceae family) was successfully induced, and its ingredients were extracted. The PCE could significantly downregulate inflammation factors such as IL-1α, IL-6 and TRPV1 in HaCaT cells, and MMPs in fibroblasts which could cause the collagen degradation induced by UVB. Meanwhile, UVB-induced DNA damage was alleviated by PCE. The analysis of histamine content in mast cells revealed that PCE effectively alleviated skin sensitivity. Furthermore, the clinical trials validated a significant increase in total collagen content in vivo, following 28 days of continuous application of a cosmetic formulation containing 1% PCE measured by Raman confocal spectroscopy technology.

CONCLUSION

The PCE could downregulate the gene expression of inflammatory factors, indicating the ability of DNA repair. The number of senescent cells was also decreased after UVB stimulation. Furthermore, the results of in vivo study showed that PCE was an ideal cosmetic ingredient for promoting collagen levels.

Effect of Penetration Enhancer on the Structure of Stratum Corneum: On-Site Study by Confocal Polarized Raman Imaging

Keratin and lipid structures in the stratum corneum (SC) are closely related to the SC barrier function. The application of penetration enhancers (PEs) disrupts the structure of SC, thereby promoting infiltration. To quantify these PE-induced structural changes in SC, we used confocal Raman imaging (CRI) and polarized Raman imaging (PRI) to explore the integrity and continuity of keratin and lipid structures in SC. The results showed that water is the safest PE and that oleic acid (OA), sodium dodecyl sulfate (SDS), and low molecular weight protamine (LMWP) disrupted the ordered structure of keratin, while azone and liposomes had less of an effect on keratin. Azone, OA, and SDS also led to significant changes in lipid structure, while LMWP and liposomes had less of an effect. Establishing this non-invasive and efficient strategy will provide new insights into transdermal drug delivery and skin health management.

Application of parelectric spectroscopy to detect skin cancer-A pilot study

BACKGROUND

The early detection of skin cancer is still challenging and calls for objective, fast diagnostic, and ideally non-invasive methods in order to leave the potentially malignant tumor cells unaltered. In this paper, the parelectric spectroscopy was applied to evaluate the potential of a non-invasive detection of basal cell carcinoma (BCC) and malignant melanoma.

MATERIALS AND METHODS

A prototype of parelectric spectroscopy was used to investigate non-invasively dipole density and mobility of suspicious skin lesions. The differences in investigated tissue were analyzed compared to pathohistological findings in a clinical study on 51 patients with suspected BCC and malignant melanoma.

RESULTS

The non-invasive parelectric spectroscopy could differentiate between normal skin, BCC, and melanoma but failed to distinguish between different types of skin cancer. The data were normalized to unsuspected nearby skin because the different skin locations influence dipole density and mobility.

CONCLUSION

The results of the pilot study indicate that the parelectric spectroscopy might be an additional, useful non-invasive diagnostic procedure to distinguish between normal skin and skin cancer.

Evaluation of acute corneal damage induced by 222-nm and 254-nm ultraviolet light in Sprague-Dawley rats

Two hundred twenty-two nanometres ultraviolet (UV) light produced by a krypton-chlorine excimer lamp is harmful to bacterial cells but not skin. However, the effects of 222-nm UV light exposure to the eye are not fully known. We evaluated acute corneal damage induced by 222- and 254-nm UV light in albino rats. Under deep anaesthesia, 6-week-old Sprague-Dawley albino rats were exposed to UV light. The exposure levels of corneal radiation were 30, 150, and 600 mJ/cm². Epithelial defects were detected by staining with fluorescein. Superficial punctate keratitis developed in corneas exposed to more than 150 mJ/cm² of UV light, and erosion was observed in corneas exposed to 600 mJ/cm² of UV light. Haematoxylin and eosin staining also showed corneal epithelial defects in eyes exposed to 254-nm UV light. However, no damage developed in corneas exposed to 222-nm UV light. Cyclobutane pyrimidine dimer-positive cells were observed only in normal corneas and those exposed to 254-nm UV light. Although some epithelial cells were stained weakly in normal corneas, squamous epithelial cells were stained moderately, and the epithelial layer that was detached from the cornea exposed to 600 mJ/cm² of light was stained intensely in corneas exposed to 254-nm UV light. In the current study, no corneal damage was induced by 222-nm UV light, which suggested that 222-nm UV light may not harm rat eyes within the energy range and may be useful for sterilising or preventing infection in the future.

Review of Modern Techniques for the Assessment of Skin Hydration

Skin hydration is a complex process that influences the physical and mechanical properties of skin. Various technologies have emerged over the years to assess this parameter, with the current standard being electrical probe-based instruments. Nevertheless, their inability to provide detailed information has prompted the use of sophisticated spectroscopic and imaging methodologies, which are capable of in-depth skin analysis that includes structural and composition details. Modern imaging and spectroscopic techniques have transformed skin research in the dermatological and cosmetics disciplines, and are now commonly employed in conjunction with traditional methods for comprehensive assessment of both healthy and pathological skin. This article reviews current techniques employed in measuring skin hydration, and gives an account on their principle of operation and applications in skin-related research.