Journal of Photochemistry and Photobiology最新文献

Ultraviolet (UV) irradiation has been identified as a key trigger for skin photoaging, characterized by the overproduction of matrix metalloproteinases (MMPs) and reactive oxygen species (ROS), along with the accelerated decomposition of extracellular matrix (ECM) proteins, ultimately contributing to the development of wrinkles. Persicaria senticosa (PS) extracts are recognized for their antioxidative properties and their importance in skin health. Nevertheless, there is a paucity of studies investigating the potential of PS in protecting the skin against photoaging. The present study aimed to assess the effectiveness of PS extracts in preventing photoaging and elucidating the molecular mechanisms involved in using immortalized human keratinocytes (HaCaT) and hairless mice. The major bioactive constituents of PS were identified as p-coumaric acid, isoquercitrin, quercetin-3-O-glucuronide, and quercetin. Aqueous extracts of PS exhibited the ability to mitigate UVB-induced cellular damage and diminished ROS generation in HaCaT cells. Moreover, treatment with PS effectively attenuated the upregulated expression of matrix metalloproteinase-1 (MMP-1) and collagen degradation induced by UVB exposure. The property of PS to counteract photoaging was related to its capacity to inhibit the UVB-induced phosphorylation of mitogen-activated protein kinase (MAPK) and suppress the subsequent activation of activator protein 1 (AP-1) signaling pathways. Moreover, in hairless mice exposed to UVB radiation, the application of PS significantly alleviated the development of skin wrinkles, diminished epidermal thickening, and mitigated collagen degradation. Notably, PS treatment resulted in the downregulation of the UVB-activated MAPK/AP-1/MMP-1 pathway in mouse skin tissues. These findings suggest that PS has the potential to serve as a therapeutic agent for treating photoaging, holding promises in both cosmeceutical and pharmaceutical applications.

It is known that cell culture micropatterns have the ability to facilitate stem cell differentiation induced by specialized chemical factors and different differentiation directions have different optimal micropattern shapes. In this study, by utilizing extrinsic photobiomodulation (EPM) with verteporfin as photosensitizer and light irradiation of 690 nm wavelength as a universal, unbiased, and synchronizing way of inducing differentiation of human umbilical cord Wharton's Jelly mesenchymal stem cells (WJ-MSCs), the topographic cue for cell type specification conveyed in microislands is investigated. It is found that the topographic cues are encoded in the symmetry and aspect ratio of microislands and conformation of cells to microislands is necessary for acquiring the cue. F-actin vertical columns form and cell thickness increases for cells on microislands, and the two effects are enhanced by EPM and correlate with cell differentiation. EPM treatment poises cells in a stationary state to initiate differentiation and the process of making commitment takes two days. Our findings reveal the way to fully exploit topographic cues for promoting and controlling cell differentiation.

Photobiomodulation (PBM) is emerging as a promising non-invasive approach for managing inflammatory skin conditions. However, its precise molecular mechanisms, especially within the green light spectrum, remain elusive. In this study, we investigated the anti-inflammatory mechanisms of 520 nm green light in primary human keratinocytes (KCs) exposed to the contact sensitizer 2,4-dinitrochlorobenzene (DNCB). Our data revealed that green light effectively reduces the mRNA expression of pro-inflammatory cytokines IL-6, IL-8, and TNF-α, comparably to the effect of dexamethasone, a conventional anti-inflammatory agent. As Nuclear factor erythroid-2-related factor 2 (Nrf2) is involved in the red light response, we explored Nrf2′s role in green light anti-inflammatory activity. Green light exposure activated the Nrf2 pathway, leading to Nrf2 increased accumulation in KCs and the induction of Nrf2 target genes, including HO-1 and GCLC. Invalidation of Nrf2 with si-RNA diminished the green light's regulatory effect, indicating Nrf2′s essential role in the green light's anti-inflammatory action. As the Transient Receptor Potential Vanilloid 1 (TRPV1) channel is a potential target for green light, we investigated its role in PBM response. Blocking TRPV1 with capsazepine (CPZ) abolished the anti-inflammatory effect of green light and prevented the upregulation of Nrf2 target genes. This finding highlights TRPV1′s integral role in green light beneficial activity via the activation of the Nrf2 pathway. Overall, our study identifies TRPV1 and Nrf2 as critical players in the green light response, highlighting the versatility of PBM in controlling skin inflammation.

A simple method for obtaining triplet-triplet absorption (TTA) spectra and triplet state (T₁) lifetimes of long-lived triplets is presented and demonstrated with the polycyclic aromatic hydrocarbon coronene (both normal and perdeuterated forms) in a polymer matrix at room temperature. The TTA spectra obtained with a camera flash and a spectrophotometer are noisier but otherwise identical to those obtained with a state-of-the-art flash photolysis apparatus. The triplet lifetimes obtained from transient absorption are identical to the phosphorescence lifetimes of the same samples.

Today's Western lifestyle leads to increasing rates of skin cancers. Photoprotection behavior has become a hot topic in the last decades. This historical review aims at understanding modern photoprotection advice, considering decades of dermatological and photobiological research. The link between social trends, the main scientific discoveries in the field of photobiology and photoprotection strategies developed by dermatologists and industrials thanks to technological advances is narrated. Photoprotection strategies evolve in response to consumers’ demands and concerns. Here are described many social shifts, from the apparition of retributed holidays to the rise of personalized cosmetic trends. In the discussion, the most up-to-date personalized dermatological advice is presented, according to a panel of dermatologists and photoprotection experts.

Objective

to evaluate the effects of photobiomodulation therapy (PBMT) in the prevention of radiodermatitis in patients with head and neck cancer and to describes a protocol for the use of low-power laser with different energy doses according to the grades of acute radiation dermatitis (ARD).

Methods and materials

This is a case series study and were evaluated the medical records of 15 patients with head and neck cancer who underwent photobiomodulation for prevention andor treatment of ARD during radiotherapy treatment at São Luiz Jabaquara Hospital in São Paulo, from January 2021 to February 2022. The data obtained were organized in a descriptive way.

Results

Of the medical records eligible for the study, three were discarded because the patients did not undergo PBMT. These three evolved to grade III radiodermatitis and radiotherapy treatment was interrupted. Among sample receiving photobiomodulation therapy during radiotherapy treatment, 50 % developed radiodermatitis. 25 % presented grade I radiodermatitis and 25 % developed grade III radiodermatitis. However, only 1 % of the sample had its radiotherapy treatment interrupted due to radiodermatitis.

Conclusion

Photobiomodulation is a safe and effective alternative in the management of radiodermatitis, but more studies are needed to establish a PBMT protocol.

Oxidative stress and inflammation in the retinal pigment epithelium (RPE) cells have been identified as significant risk factors in the development and progression of retinal associated diseases including age-related macular degeneration (AMD). In addition, AMD and myopia have been associated with impaired dopamine activity. Treatment of RPE cells with antioxidants or high concentrations of l-DOPA (levodopa), which down-regulates vascular endothelial growth factor (VEGF) via a G-protein-coupled receptor GPR143, slow AMD progression. To develop a targeted and effective treatment aimed at improving the viability of RPE cells we examined small molecular weight thiol-based and levodopa containing molecules. These include the N-acetylcysteine amide (AD4/NACA), SuperDopa-Amide (SDA), and members of the thioredoxin mimetic (TXM) family of peptides, TXM-CB13, TXM-CB30, and SuperDopa (SD). We show that these antioxidant/anti-inflammatory reagents protect ARPE-19 cells from photic stress mediated by rose Bengal (rB) and rhodopsin-rich POS, and from non-photic stress induced by oxidation with sodium iodate. Protection is correlated with a reduction in DPPH radical and singlet-oxygen quenching. Compared to GSH the bimolecular rate-constants of singlet oxygen quenching in aqueous solution by the levodopa derivatives SD and SDA were two-fold higher. Inhibition of auranofin-induced activation of the mitogen-activation-kinases (MAPK's) JNK1/2 and ERK1/2 confirmed the antioxidant/anti-inflammatory activity of the thiol-levodopa derivatives. The antioxidant and radical scavenging activities of TXM-CB13 and TXM-CB30, or SD and SDA, which combine redox activity with elevating cellular levodopa, might offer an efficient protection of RPE cells. These retino-protective peptides are potential drug candidates destined for slowing the onset and/or progression of RPE-related disorders.

Alternate cobalt redox mediator based dye-sensitized solar cells (DSCs) are getting widespread attention taking advantage of their one-electron transfer mechanism compared to the conventional iodide/triiodide electrolyte. In the present study, we used indole fused heterocyclic organic sensitizers having indolo[3,2-b]indole as donor with three different π-spacers [(benzene (IID-1), thiophene (IID-2) and furan (IID-3)] along with cobalt bipyridine derivatives as redox mediators having different peripheral substituents {[Co(bpy)₃]^3+/2+, [Co(Me₂bpy)₃]^3+/2+, and [Co(t-Bu₂bpy)₃]^3+/2+}. A detailed investigation was carried out to understand the fundamental charge transfer processes and loss mechanism happening at the various interfaces as a function of structural variations in the present dye-electrolyte combinations. Among the investigated systems, higher performance was obtained for the association of furan substituted dye (IID-3) with [Co(t-Bu₂bpy)₃]^3+/2+ electrolyte. The importance of choosing the right combination of sensitizer and electrolyte is critical to realize higher performance in dye-sensitized solar cells particularly while employing organic dyes and alternate metal complex redox electrolytes which was systematically investigated in the present manuscript.

It is well known that life has evolved to use and generate light, for instance, photosynthesis, vision and bioluminescence. What is less well known is that during normal metabolism, it can generate 1–100 photons s⁻¹ cm^–2 known as ultra-weak photon emission (UPE), biophoton emission or biological autoluminescence. The highest generation of these metabolic photons seem to occur during oxidative stress due to the generation and decay of reactive oxygen species (ROS), and their interaction with other components of the cell. To study this further, we have configured a sensitive detection system to study photon emission in germinating mung beans.

Here we investigated growing mung beans over 7 days at a constant temperature of 21 ± 1 °C in a light tight box, using dual top and bottom opposing photomultiplier tubes. Over this time period we showed that in total, mung beans grown from seeds generated an average of 5 ± 1 counts s⁻¹ above background. As the new bean stems grew, they showed a gradual linear increase in emission of up to 30 ± 1 counts s⁻¹, in agreement with previous literature. In addition to this “steady-state” emission we also observe delayed luminescence and drought-stress response emission previously observed in other species. Finally, we also observe episodic increased emission events of between 2 and 15 counts s⁻¹ for durations of around 3 h detected underneath the sample, and assign these to the growing of secondary roots.

We then induce secondary root formation using aqueous solutions of growth hormones hydrogen peroxide (H₂O₂, 167 µM) or 3-indole acetic acid (IAA, 0.5 µM) for watering. Both hormones show prolonged increase in emission above steady-state, over days 3–5 with at least 3 times the number of secondary roots formed compared with water alone. We also observed a significant peak increase in photon emission (474 and 1738 cps vs. 28 and 55 cps for water alone) for the H₂O₂ which we attribute to direct ROS reaction emission as confirmed by measurement on dead plants.

Altogether we have expanded upon and demonstrated an instrument and biological system for reliably producing and measuring intrinsic metabolic photons, first observed 100 years ago by Alexander Gurwitsch.

Photosensitivity to structurally diverse drugs is a common but under-reported adverse cutaneous reaction and can be classified as phototoxic or photoallergic. Phototoxic reactions occur when the skin is exposed to sunlight after administering topical or systemic medications that exhibit photosensitizing activity. These reactions depend on the dose of medication, degree of exposure to ultraviolet light, type of ultraviolet light, and sufficient skin distribution volume. Accurate prediction of the incidence and phototoxic response severity is challenging due to a paucity of literature, suggesting that phototoxicity may be more frequent than reported. This paper reports an extensive literature review on phototoxic drugs; the review employed pre-determined search criteria that included meta-analyses, systematic reviews, literature reviews, and case reports freely available in full text. Additional reports were identified from reference sections that contributed to the understanding of phototoxicity. The following drugs and/or drug classes are discussed: amiodarone, voriconazole, chlorpromazine, doxycycline, fluoroquinolones, hydrochlorothiazide, nonsteroidal anti-inflammatory drugs, and vemurafenib. In reviewing phototoxic skin reactions, this review highlights drug molecular structures, their reactive pathways, and, as there is a growing association between photosensitizing drugs and the increasing incidence of skin cancer, the consequential long-term implications of photocarcinogenesis.