Photochemistry and Photobiology最新文献

Gliomas are malignant tumors of the central nervous system, and one severe variant is called gliosarcoma. Photodynamic therapy (PDT) is a technique that stands out in the oncology area for minimizing side effects for the patient, triggering cell death at the site of irradiation, and can be used concomitantly with conventional treatments. This study aimed to evaluate the interaction of chlorine e6 with the cytoskeleton and mitochondria, as well as morphological changes and the death mechanism triggered after PDT. Chlorin e6 was used at concentrations of 200, 12.5, and 6.25 μg/mL, and cytoskeletal changes were analyzed by alpha-tubulin staining and mitochondrial membrane potential (MMP) analysis by JC-1 and Rhodamine 123 in flow cytometry. Surface features were examined using scanning electron microscopy, and the type of cell death mechanism was determined by flow cytometry with annexin and propidium iodide. Changes in the cytoskeleton were observed after PDT. Cytometry showed that cell death occurred predominantly via the apoptosis pathway, followed by the necrosis pathway. Chlorin e6 associated with PDT causes damage to gliosarcoma cells, regardless of concentration, showing cytoskeletal disruption, a decrease in MMP, and the percentage of cell death varies according to the concentration of PS.

Cutaneous overexposure to ultraviolet radiation has a variety of deleterious effects. The extent to which dietary factors are effective at moderating UV damage is a significant issue. Grapes contain phytochemicals that protect against excessive UV damage. Components of grapes, in particular resveratrol, proanthocyanidins, and cyanidin-3-glucoside, are receiving considerable attention for their photoprotective actions because of their lack of toxicity, abundance, and low cost. Resveratrol and proanthocyanidins are potent antioxidants that interfere with signal transduction and immunosuppressive pathways activated by UV radiation, which are responsible for its harmful effects. Studies in humans provide a rationale for their further development as a novel method of photoprotection.

The International Agency for Research on Cancer (IARC) stated that circadian disruption is a potential carcinogen. However, the impact of environmental carcinogens, including sub-erythemal doses of UVB exposure, on circadian rhythms remains unclear. We evaluated the impact of long-term rotating shift, loss of Per1/2 genes, and chronic UVB exposure on the circadian rhythms of SKH-1 mice for up to 7 months. Real-time locomotion and circadian gene expression were measured in these animals. Mice under rotating shift exhibited a longer period of activity of up to 25.20 h, while those under standard light conditions had a clear 24-h rhythm. mPer1/mPer2 mice, conversely, displayed a shortened period of activity of 23.61 h. Interestingly, chronic UVB exposure had no impact on activity rhythms, though it induced skin tumors in all mice. Rotating shift and loss of mPer1/mPer2 led to circadian dysregulation of all core clock genes, with a notable phase difference in Cry1. These findings provide novel insights into environmental and genetic influences on circadian rhythms.

There is a growing need for a skin model that combines the natural physiology of skin while reducing reliance on mice. Natural physiology is achieved by using fresh, intact skin explants sourced from living organisms such as humans or mice. This study focused on the standardization and characterization of an in vitro mouse skin explant model for investigating solar ultraviolet (sUV)-induced skin damage. We developed a protocol to use skin explants derived from the discarded tissue of mice after euthanasia. These explants consist of intact dermal and epidermal layers suspended in cell culture medium and maintained in vitro. To assess the viability of the skin explants, we evaluated tissue morphology (via hematoxylin and eosin [H&E] staining), viability markers, and DNA damage markers. Our ex vivo model preserves the key characteristics and physiological responses of in vivo skin for short incubation periods, while minimizing the use of mice. This model enables the study of DNA damage and repair, and it has broad applications, including studies on skin photoprotection, topical treatments, drug development, and cosmetics.

Spectral Solar Photosynthetically Photon Flux Density (PPFD) (380-780 nm) reaching the surface in different tree shade conditions and heights has been analyzed in order to better understand the different photosynthetic performance of plants depending on their spatial situation, the canopy density and height with respect to the floor. A comparison between the shadow of nine different trees in a sunny day and the case of a cloudy day in an open space has been studied. A poplar, laurel, amber tree, pine, olive tree, fir tree, cypress, elm tree and magnolia tree have been analyzed. The study has been developed in Valencia (Spain) during July and August 2022. Conditions with higher PPFD received are found to be, apart from those of a sunny day, those for cloudy day, and those for the shade of cypress. The case in which less amount of PPFD is received is that under the shade of olive tree. Both with a spectral maximum in the Blue region. It is also remarkable that the PPFD radiation is proportional to the height of measurement at 10 h, but this relationship changes, and at 13 h the relationship between irradiance received and height of measurement is inversely proportional.

Dissolving microneedles (DMNs) is a promising technology for transdermal and intradermal drug delivery. However, effective decontamination protocols are necessary to ensure safety and efficacy in clinical applications. The challenge is to use a technique that preserves mechanical properties, does not introduce chemicals, and can decontaminate DMNs without affecting the drug. With its potent antimicrobial properties and minimal residual effects, ozone presents a novel and safe method for decontaminating DMNs. Specifically, the present study assesses ozone's efficacy in decontaminating DMNs loaded with aminolevulic acid, intended for photodynamic therapy in skin cancer treatment. The results showed that it effectively decontaminates E. coli and S. aureus without compromising the polymer properties or promoting drug degradation. Overall, ozone represents an approach that can be adopted to decontaminate DMNs, offering a safer and effective strategy that enhances their potential to translate to clinical application.

Chlorophyll(Chl)-a derivatives inserting an ethynylene-naphthylene linker between the chlorin π-skeleton and hydroxymethyl group were prepared as models of chlorosomal Chls. Their syntheses were achieved via Sonogashira coupling reaction. Their J-aggregation behaviors were investigated by electronic absorption and circular dichroism spectroscopic measurements. These studies revealed that the 2,6-naphthylene inserted Chl-a derivatives gave the single J-aggregation species in an aqueous Triton X-100 micellar solution with a larger red-shift value (1270 cm^-1) of the Qy band in spite of its longer linker compared with p-phenylene inserted Chl-a derivative (970 cm^-1). These unique optical properties were also discussed based on the computational studies, which indicated the different positional relation of chlorin rings in the assemblies by the linker structure.

Ultraviolet-C (UV-C) at a wavelength of 254 nm is used for disinfection but cannot be used in dwelling space because it is harmful to the human body, while 222-nm Far UV-C shows germicidal effect and poses little hazardous effect to human. Formation of cyclobutane pyrimidine dimers (CPD) of DNA is a main mechanism of UV-C germicidal effect. CPD formed by irradiation with 254-nm UV-C is repaired and bacterial proliferation is recovered by photoreactivation. In this study, we investigated photoreactivation of Staphylococcus aureus irradiated with 222-nm Far UV-C. The proliferative effect of 222-nm Far UV-C irradiated S. aureus by photoreactivation was inferior to that of irradiated with 254-nm UV-C. The 254-nm UV-C wavelength and 222-nm Far UV-C induced CPD in S. aureus cells, and the same level of CPD was repaired in cells irradiated with either UV-C after photoreactivation. It has been reported that UV-C induces generation of reactive oxygen species (ROS) in bacteria and that ROS oxidize and inactivate a variety of biomolecules in bacteria. This study showed that more ROS-producing S. aureus were observed after irradiation with 222-nm Far UV-C compared with 254-nm UV-C. These results indicate that ROS may be involved in lower recovery of 222-nm Far UV-C irradiated S. aureus by photoreactivation.

Onychomycosis, predominantly induced by Trichophyton rubrum, is a pervasive nail disorder within dermatology known for its high relapse rates and suboptimal patient adherence to treatment regimens. While photomedicine has emerged as a promising therapeutic modality, efficiency reductions are common due to deck obstruction in conventional light therapy. The spectral flexibility of LEDs offers a compelling solution, allowing for deeper deck penetration while maintaining efficacy. We have developed an advanced LED system with optimized optical parameters and have elucidated the antimicrobial mechanisms underlying this technology. Our research shows that an optimal wavelength of 405 nm, an energy density of 396 J/cm², and an average light intensity of 140 mW/cm² demonstrate superior efficacy in treating onychomycosis. The antifungal mechanism of our pulsed LED system involves the induction of reactive oxygen species (ROS) within fungal mycelia, ultimately resulting in membrane damage. These insights highlight the potential of LED lighting systems as a novel antimicrobial strategy, offering a promising avenue for the treatment of onychomycosis.

This study investigates the effects of photobiomodulation (PBM) with a 660-nm laser on nerve regeneration and muscle morphometry following median nerve axonotmesis in rats. Sixteen Wistar rats were divided into a control group and laser-treated group, with the latter receiving 10 applications of PBM (660 nm; 20 mW; 10 J/cm²; 0.4 J; and 20 s) over 2 weeks. Functional analysis was performed using the grasping test, which measures the grip strength of the forelimb digits to evaluate motor function of the median nerve. Morphometric analyses were conducted on the median nerve, flexor digitorum (FD) muscle, and flexor carpi radialis (FCR) muscle. PBM led to functional improvement, with significant differences observed on the 21st day post-injury. However, no significant differences between groups were found in nerve morphometry. Morphometric analysis of the FD muscle revealed significant improvements in the PBM group, but with no significant differences regarding the FCR muscle. These findings suggest that 660-nm laser with the parameters used produced functional improvement as well as significant improvements in the morphometry of the FD muscle, but did not have significant effects on the morphometry of the FCR muscle or nerve regeneration.