Irradiated Mouse Skin Research Articles

The effects of extracorporeal shock wave therapy on cutaneous radiation injury in a mouse model.

Although radiation-induced skin injuries are a concern in patients receiving radiation therapy, there are few effective treatments. The aim of this study was to evaluate the protective effects of extracorporeal shock wave therapy (ESWT) on irradiated fibroblasts and mouse skin. In the in vitro study of human dermal fibroblasts, the experimental group was subjected to ESWT following irradiation (20 Gy). The control groups were only irradiated or only subjected to ESWT. At 24 or 48 h post-ESWT, cell viability, cell migration, and mRNA and protein expression were measured. In the in vivo study, the experimental group (7 mice) was treated with ESWT following irradiation (45 Gy). The control group (7 mice) was only irradiated. At 8 weeks post-irradiation, dorsal skin was harvested for histopathologic examination and protein isolation. In dermal fibroblasts, treatment with ESWT increased viability of irradiated cells compared with irradiated-only and untreated cells (p = 0.005). ESWT increased cell migration 24 h post-irradiation (p = 0.002), and decreased TGF-β1 protein expression 48 h post-irradiation (p = 0.024). In mice, ESWT decreased the level of radiation-related skin injury (p = 0.006). Treatment of irradiated skin with ESWT decreased TGF-β1 (p = 0.009) and phospho-Smad3 (p = 0.009) protein expression, as well as decreasing myofibroblasts (p = 0.047) and increasing vessel density (p < 0.001). Our study demonstrated that ESWT alleviated radiation-induced fibrosis by downregulating TGF-β1 expression. It suggests the potential of ESWT for the treatment of radiation-induced fibrosis.

ScRNA-seq transcriptomic profiling of irradiated mouse skin reveals altered cell types, pathways, and cell-cell interactions

ObjectiveTo investigate the substantial changes in cell types, pathways, and cell-cell interactions occurring in the irradiation-induced alopecia and dermatitis (IRIAD) mouse model and to identify potential targets for patients experiencing skin adverse reactions to radiotherapy. MethodsMice were irradiated at 15 ​Gy, targeting the head and neck region. After a 14-day interval, living cells were extracted from both wild-type (WT) mice and irradiated mice for single-cell RNA sequencing (scRNA-seq). The scRNA-seq data, retrieved from the GEO database (GSE201447), underwent stringent quality control using the Seurat (v4.3.0) R package. Cell type annotation relied on previously reported typical markers and CellMarker 2.0. Differentially expressed genes were calculated to perform gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. Cell-cell interactions were evaluated using the Cellchat R package. ResultsThe application of single-cell RNA sequencing (scRNA-seq) enabled a comprehensive characterization of the intricate cellular composition of both wild-type (WT) and irradiated mice skin. Remarkably, cells within irradiated mice skin exhibited a significant alteration in the intensity of cell-cell interactions compared to their wild-type counterparts. This change in interaction intensity was observed across various cell types, including fibroblast cells, endothelial cells, and dendritic cells. Importantly, these "interacting cells" shared common signaling pathways, notably the upregulation of the IL-17 pathway following irradiation. ConclusionsThe modification of intercellular communication induced by irradiation primarily involves fibroblast cells, endothelial cells, and various types of immune cells. This investigation provides a novel perspective on potential targets and holds promise for enhancing the clinical management of IRIAD.

Kaempferide Prevents Photoaging of Ultraviolet-B Irradiated NIH-3T3 Cells and Mouse Skin via Regulating the Reactive Oxygen Species-Mediated Signalings.

Kaempferide (KFD) is a naturally occurring flavonoid that exists in various medicinal plants. The pharmaceutical properties of KFD, including its anti-cancer, antioxidant and anti-diabetic effects, have been noted, but the effects of KFD on photoaging and their underlying molecular mechanism have yet to be elucidated. In this study, we investigated the effects of KFD on Ultraviolet-B (UVB)-mediated photoaging processes using in vitro and in vivo photoaging model systems. The topical administration of KFD on mouse dorsal areas suppressed UVB-mediated wrinkle formation and epidermal thickening. In addition, the UVB-mediated reduction of dermal collagen content, which was estimated by Masson's trichrome staining, was recovered through KFD treatments. Furthermore, we found that UVB-induced abnormal values of procollagen type-1 (COL1A1), metalloproteinases (MMP-1a and MMP-3) and proinflammatory cytokines (IL-8, MCP-3 and IL-6) on mouse skin tissue as well as NIH-3T3 cells was recovered through KFD treatment. The administration of KFD to NIH-3T3 cells suppressed the UVB-mediated upregulation of reactive oxygen species (ROS), mitogen-activated protein kinases (MAPKs) and AKT phosphorylation. Furthermore, the treatment of ROS inhibitor restored the UVB-induced MAPKs and AKT phosphorylation as well as the abnormal expression of photoaging related genes. These findings indicate that KFD can attenuate UVB-induced ROS elevation to elicit anti-photoaging activity. Taken together, our data suggest that KFD could be developed as a potential natural anti-photoaging agent.

Decellularized Adipose Matrices Can Alleviate Radiation-Induced Skin Fibrosis.

Objective: Radiation therapy is commonplace for cancer treatment but often results in fibrosis and atrophy of surrounding soft tissue. Decellularized adipose matrices (DAMs) have been reported to improve these soft tissue defects through the promotion of adipogenesis. These matrices are decellularized by a combination of physical, chemical, and enzymatic methods to minimize their immunologic effects while promoting their regenerative effects. In this study, we aimed at exploring the regenerative ability of a DAM (renuva®; MTF biologics, Edison, NJ) in radiation-induced soft tissue injury. Approach: Fresh human lipoaspirate or DAM was injected into the irradiated scalp of CD-1 nude mice, and volume retention was monitored radiographically over 8 weeks. Explanted grafts were histologically assessed, and overlying skin was examined histologically and biomechanically. Irradiated human skin was also evaluated from patients after fat grafting or DAM injection. However, integrating data between murine and human skin in all cohorts is limited given the genetic variability between the two species. Results: Volume retention was found to be greater with fat grafts, though DAM retention was, nonetheless, appreciated at irradiated sites. Improvement in both mouse and human irradiated skin overlying fat and DAM grafts was observed in terms of biomechanical stiffness, dermal thickness, collagen density, collagen fiber networks, and skin vascularity. Innovation: This is the first demonstration of the use of DAMs for augmenting the regenerative potential of irradiated mouse and human skin. Conclusions: These findings support the use of DAMs to address soft tissue atrophy after radiation therapy. Morphological characteristics of the irradiated skin can also be improved with DAM grafting.

Protective effects of halophyte complex extract against UVB-induced damage in human keratinocytes and the skin of hairless mice.

Limonium tetragonum, Triglochin maritimum, Artemisia scoparia and red ginseng have been used as folk remedies for treating a variety of diseases. In the current study, the protective effects of halophyte and red ginseng against ultraviolet (UV)-induced skin damage were investigated. Halophyte red ginseng complex extract (HRCE) was prepared and its effects on UV-B irradiated human keratinocytes and mouse skin were studied through ELISA, Western blotting immunofluorescence and histological staining. HRCE inhibited peroxide-induced damage in human keratinocytes. HRCE also inhibited UVB-induced collagen and elastin degradation in human keratinocytes and mouse skin. In addition, HRCE inhibited mast cell infiltration in the skin of mice irradiated with UVB light. This effect was likely due to HRCE inhibiting the activation of MAPK and NF-κB. By protecting the skin from UVB-induced skin damage, HRCE has the potential to be used in the treatment and prevention of UV-induced skin damage and photoaging.

The Protective Effect of Polyherbal Formulation, Harak Formula, on UVA-Induced Photoaging of Human Dermal Fibroblasts and Mouse Skin via Promoting Nrf2-Regulated Antioxidant Defense.

Polyherbal formulation combining multiple herbs is suggested to achieve enhanced therapeutic effects and reduce toxicity. Harak herbal formula (HRF) extracts were proposed to regulate skin responses to UVR through their ability to suppress UVA-induced matrix metalloproteinase-1 (MMP-1) and pigmentation via promoting antioxidant defenses in in vitro models. Therefore, natural products targeting Nrf2 (nuclear factor erythroid 2-related factor 2)-regulated antioxidant response might represent promising anti-photoaging candidates. Hesperetin (HSP) was suggested as a putative bioactive compound of the HRF, as previously shown by its chemical profiling using the liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). In this study, we explored the anti-photoaging effects of HRF extracts and HSP on normal human dermal fibroblasts (NHDFs) and mouse skin exposed to UVA irradiation. Pretreatment of NHDFs with HRF extracts and HSP protected against UVA (8 J/cm2)-mediated cytotoxicity and reactive oxygen species (ROS) formation. The HRF and HSP pretreatment also attenuated the UVA-induced MMP-1 activity and collagen depletion concomitant with an upregulation of Nrf2 activity and its downstream genes (GST and NQO-1). Moreover, our findings provided the in vivo relevance to the in vitro anti-photoaging effects of HRF as topical application of the extracts (10, 30 and 100 mg/cm2) and HSP (0.3, 1, and 3 mg/cm2) 1 h before UVA exposure 3 times per week for 2 weeks (a total dose of 60 J/cm2) mitigated MMP-1 upregulation, collagen loss in correlation with enhanced Nrf2 nuclear accumulation and its target protein GST and NQO-1 as well as reduced 8-hydroxy-2′-deoxyguanosine (8-OHdG) in irradiated mouse skin. Thus, our findings revealed that HRF extracts and HSP attenuated UVA-induced photoaging via upregulating Nrf2, together with their abilities to reduce ROS formation and oxidative damage. Our study concluded that the HRF and its bioactive ingredient HSP may represent potential candidates for preventing UVA-induced photoaging via restoration of redox balance.

Biomarker function of HMGA2 in ultraviolet-induced skin cancer development.

The high mobility group AT-hook 2 (HMGA2) gene encodes a transcription factor that is expressed during embryonic development but down-regulated in adult tissues. Its re-expression in adult tissues is often associated with tumorigenesis. In this study, we found that HMGA2 is highly expressed in human cutaneous squamous cell carcinoma (SCC) cell lines and primary SCC tumors, but not in adjacent normal skin. In non-ultraviolet (UV)-irradiated mouse skin, baseline Hmga2 expression was detected in the epidermis but not in hair follicles. Following chronic UV exposure, we found activation of Hmga2 in hair follicles. UV-induced mouse skin SCC tumors displayed a ubiquitous increase in Hmga2 expression compared to non-tumor-bearing adjacent skin. In human SCC cells, decreased HMGA2 expression was linked with reduced cell proliferation following depletion of FOXM1 and TRIP13, two UV master regulator genes. Taken together, these findings highlight an important biomarker function of HMGA2 expression in UV-induced skin tumorigenesis and cell proliferation.

Topical Application of Phlorotannins from Brown Seaweed Mitigates Radiation Dermatitis in a Mouse Model.

Radiation dermatitis (RD) is one of the most common side effects of radiotherapy; its symptoms progress from erythema to dry and moist desquamation, leading to the deterioration of the patients’ quality of life. Active metabolites in brown seaweed, including phlorotannins (PTNs), show anti-inflammatory activities; however, their medical use is limited. Here, we investigated the effects of PTNs in a mouse model of RD in vivo. X-rays (36 Gy) were delivered in three fractions to the hind legs of BALB/c mice. Macroscopic RD scoring revealed that PTNs significantly mitigated RD compared with the vehicle control. Histopathological analyses of skin tissues revealed that PTNs decreased epidermal and dermal thickness compared with the vehicle control. Western blotting indicated that PTNs augmented nuclear factor erythroid 2-related factor 2 (NRF2)/heme oxygenase-1 (HO-1) pathway activation but attenuated radiation-induced NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) and inflammasome activation, suggesting the mitigation of acute inflammation in irradiated mouse skin. PTNs also facilitated fast recovery, as indicated by increased aquaporin 3 expression and decreased γH2AX (histone family member X) expression. Our results indicate that topical PTN application may alleviate RD symptoms by suppressing oxidative stress and inflammatory signaling and by promoting the healing process. Therefore, PTNs may show great potential as cosmeceuticals for patients with cancer suffering from radiation-induced inflammatory side effects such as RD.

Abstract 1: Transdermal Deferoxamine Alleviates Radiation-Induced Damage In Porcine Skin

Purpose: Adjuvant radiation therapy is an effective treatment for oncologic malignancies; however, it can cause adverse collateral effects to surrounding soft tissue such as dermal thickening, destruction of vessels, and loss of skin elasticity making reconstruction a burden. To alleviate these detrimental effects, we tested the efficacy of a novel transdermal drug delivery system (TDDS) to provide cutaneous delivery of deferoxamine (DFO) to irradiated porcine skin. DFO is an FDA approved drug which stabilizes hypoxia-inducible factor-1 alpha to increase tissue vascularization. Direct inject of DFO has previously been shown to improve irradiated mouse skin. We hypothesize that application of the DFO TDDS to irradiated soft tissue will also improve radiation-induced fibrosis in our pig model. Methods: Three, red Duroc pigs (three months old) were irradiated with a single fraction of 30 Gray delivered to 5 equal localized regions on either side. The pigs were allowed to recover for eight weeks allowing for chronic radiation damage to develop. At the end of recovery period, the pigs were divided into 3 treatment conditions: 1% DFO TDDS patch, control TDDS patch with not medication, and no treatment. Biopsies from each group, with their respective adjacent non-irradiated skin, were acquired at 1, 2, 3, 4, and 8 week time points. Histological sections were stained with hematoxylin and eosin and Picrosirius Red to evaluate dermal thickness and collagen deposition. Vascularity was determined by CD31 immunofluorescence staining. Mechanical testing was performed to determine skin stiffness, and cutometer readings for each condition were performed to test for skin deformation. Results: Skin histology revealed that DFO TDDS treated irradiated skin demonstrated significant reduction in dermal thickness (hematoxylin and eosin), lower collagen content (Picrosirius Red), and higher vascularity (CD31 immunofluorescence) compared to no patch (***p<0.001, **p<0.01, *p<0.05, respectively) and control patch treated skin (*p<0.05, ****p<0.0001, **p<0.01, respectively). Furthermore, mechanical testing of DFO treated skin exhibited decreased stiffness starting from week 2 onwards after patch placement. Finally, overall skin deformation, from cutometer data, was higher for DFO treated skin compared to the control and no patch treatment groups. Conclusions: Currently, there are limited effective treatments for radiation-induced skin damage. The DFO TDDS patch provides a method to mitigate the chronic effects of radiation-induced skin damage for oncological patients who are in need of reconstructive surgery. The histological and immunofluorescent data indicate the morphological characteristics of the irradiated skin after DFO TDDS patches are similar to normal skin. Furthermore, the mechanical properties of the irradiated skin after DFO TDDS patches mirror normal skin. As porcine skin closely resembles human skin, our findings establish incredible potential to treat patients with radiation induced soft tissue fibrosis.

Anti‑photoaging effect of fermented agricultural by‑products on ultraviolet B‑irradiated hairless mouse skin.

Processed products from agricultural produce generate a large number of agricultural by-products that contain a number of functional substances. These are often discarded owing to the lack of suitable processing methods. The present study investigated the anti-photoaging properties of fermented rice bran (FRB), soybean cake (FSB) and sesame seed cake (FSC) on ultraviolet B (UVB)-irradiated hairless mouse skin. Results indicated that the oral administration of FRB, FSB and FSC effectively inhibited the UVB irradiation-induced expression of matrix metalloproteinase (MMP)-2, MMP-9, MMP-3 and MMP-13. Reverse transcription-quantitative polymerase chain reaction results also demonstrated that FRB, FSB and FSC significantly inhibited the UVB-induced expression of the genes encoding tumor necrosis factor-α, inducible nitric oxide synthase, interleukin (IL)-6 and IL-1β when compared with the UVB-vehicle group (P<0.05). Additionally, collagen degradation and mast cell infiltration were reduced in hairless mouse skin. Furthermore, UVB-induced wrinkle formation was also significantly reduced in mouse skin compared with the UVB-vehicle group (P<0.05). These results reveal that fermented agricultural by-products may serve as potential functional materials with anti-photoaging activities.

The SOD Mimic, MnTE-2-PyP, Protects from Chronic Fibrosis and Inflammation in Irradiated Normal Pelvic Tissues.

Pelvic radiation for cancer therapy can damage a variety of normal tissues. In this study, we demonstrate that radiation causes acute changes to pelvic fibroblasts such as the transformation to myofibroblasts and the induction of senescence, which persist months after radiation. The addition of the manganese porphyrin, MnTE-2-PyP, resulted in protection of these acute changes in fibroblasts and this protection persisted months following radiation exposure. Specifically, at two months post-radiation, MnTE-2-PyP inhibited the number of α-smooth muscle actin positive fibroblasts induced by radiation and at six months post-radiation, MnTE-2-PyP significantly reduced collagen deposition (fibrosis) in the skin and bladder tissues of irradiated mice. Radiation also resulted in changes to T cells. At two months post-radiation, there was a reduction of Th1-producing splenocytes, which resulted in reduced Th1:Th2 ratios. MnTE-2-PyP maintained Th1:Th2 ratios similar to unirradiated mice. At six months post-radiation, increased T cells were observed in the adipose tissues. MnTE-2-PyP treatment inhibited this increase. Thus, MnTE-2-PyP treatment maintains normal fibroblast function and T cell immunity months after radiation exposure. We believe that one of the reasons MnTE-2-PyP is a potent radioprotector is due to its protection of multiple cell types from radiation damage.

Cytokine profiles in mice tissues after irradiation of the thymus projection area with femtosecond laser

The effects of pulsed femtosecond laser irradiation in the near ultraviolet region on the levels of cytokines in the thymus, blood, and skin of irradiated mice have been studied. Irradiation of the thymus projection area with low-intensity laser radiation in the near UV region of the spectrum showed significant changes in cytokine levels in the skin and thymus and, to a lesser extent, in the blood of irradiated mice. Laser irradiation with a power density of 20 mW/cm2 affects the cytokine profile in the thymus: IFN-γ, IL-3, IL-4, IL-5, eotaxin, GM-CSF, and chemokine KC–factors that can affect differentiation and proliferation of the cells of the immune system in the gland. Conclusions: It is assumed that changes in the expression of cytokines in the thymus after laser irradiation are explained by the rearrangement of biochemical processes possibly associated with the maturation of cells in the gland.

Leptin induction following irradiation is a conserved feature in mammalian epithelial cells and tissues

Purpose: Leptin (LEP) is a peptide hormone with multiple physiological functions. Besides its systemic actions, it has important peripheral roles such as a mitogen action on keratinocytes following skin lesions. We previously showed that LEP mRNA is significantly induced in response to neutron irradiation in mouse skin and that the protein increases in the irradiated epidermis and in the related subcutaneous adipose tissue. In this work, we investigated the post-transcriptional regulation of LEP by miRNAs and the conservation of LEP’s role in radiation response in human cells.Methods: We used microarray analysis and real-time polymerase chain reaction (RT-PCR) to analyze modulation of miRNAs potentially targeting LEP in mouse skin following irradiation and bioinformatic analysis of transcriptome of irradiated human cell lines and cancer tissues from radiotherapy-treated patients to evaluate LEP expression.Results and conclusions: We show that a network of miRNAs potentially targeting LEP mRNA is modulated in irradiated mouse skin and that LEP itself is significantly modulated by irradiation in human epithelial cell lines and in breast cancer tissues from radiotherapy-treated patients. These results confirm and extend the previous evidence that LEP has a general and important role in the response of mammalian cells to irradiation.

Transcutaneous drug delivery by liposomes using fractional laser technology.

Transdermal delivery of hydrophilic peptides remains a challenge due to their poor cellular uptake and transdermal penetration. We hypothesize that combination of a CO2 fractional laser to enhance percutaneous absorption and liposomes as transdermal carriers would improve skin penetration of hydrophilic drugs. NA. Liposomes were prepared using membrane fusion lipid dioleoylphosphatidylethanolamine, and used to deliver 5-carboxyfluorescein (CF) and fluorescein isothiocyanate-conjugated ovalbumin (OVA-FITC) as model hydrophilic peptide drugs. Liposome size was estimated by dynamic light scattering. Liposome uptake into murine macrophage cells and penetration or permeation into Yucatan micropig skin after irradiation by CO2 fractional laser at varying energy levels (laser power and exposure duration) were investigated using Franz cell and fluorescence microscopy. Oxidative damage to the irradiated mouse skin was assessed by electron spin resonance. Size of CF and OVA-FITC encapsulated liposomes was 324 ± 75 nm. Cellular uptake of OVA-FITC delivered by liposomes was 10-fold higher (1,370 relative fluorescence units, RFU) than delivered in solution form (130 RFU). Fractional laser irradiation increased skin permeation rate of CF liposomes (0-10%) and OVA-FITC liposomes (4-40%) in a dose-dependent manner. Although peeling off the stratum corneum facilitated CF liposome penetration at low energy levels (2.69-3.29 J/cm2 ; 10-20 W for 500 μs), drug permeation was similar (7-8%) in peeled or untreated skin at higher laser energy levels (6.06 J/cm2 ; 20 W for 1,500 μs). FITC penetrated deeper in the skin after laser irradiation. However, OH, O2-, and VC reactive oxygen species were generated upon irradiation of the skin with a fractional CO2 laser. Increasing laser power and irradiation, time increased liposome uptake by cells and penetration of peptide drugs across the skin in a dose-dependent manner. High-energy CO2 fractional laser overcomes the rate-limiting barrier function of the stratum corneum. Further investigations are required to establish the safety and efficacy of fractional laser-irradiation assisted delivery of liposome-encapsulated drugs as a transcutaneous drug delivery system. Lasers Surg. Med. 49:525-532, 2017. © 2016 Wiley Periodicals, Inc.

Retinoid X Receptor Agonists Upregulate Genes Responsible for the Biosynthesis of All-Trans-Retinoic Acid in Human Epidermis.

UAB30 is an RXR selective agonist that has been shown to have potential cancer chemopreventive properties. Due to high efficacy and low toxicity, it is currently being evaluated in human Phase I clinical trials by the National Cancer Institute. While UAB30 shows promise as a low toxicity chemopreventive drug, the mechanism of its action is not well understood. In this study, we investigated the effects of UAB30 on gene expression in human organotypic skin raft cultures and mouse epidermis. The results of this study indicate that treatment with UAB30 results in upregulation of genes responsible for the uptake and metabolism of all-trans-retinol to all-trans-retinoic acid (ATRA), the natural agonist of RAR nuclear receptors. Consistent with the increased expression of these genes, the steady-state levels of ATRA are elevated in human skin rafts. In ultraviolet B (UVB) irradiated mouse skin, the expression of ATRA target genes is found to be reduced. A reduced expression of ATRA sensitive genes is also observed in epidermis of mouse models of UVB-induced squamous cell carcinoma and basal cell carcinomas. However, treatment of mouse skin with UAB30 prior to UVB irradiation prevents the UVB-induced decrease in expression of some of the ATRA-responsive genes. Considering its positive effects on ATRA signaling in the epidermis and its low toxicity, UAB30 could be used as a chemoprophylactic agent in the treatment of non-melanoma skin cancer, particularly in organ transplant recipients and other high risk populations.

Topical application of baby- and adult-aloe on ultraviolet B irradiated mouse skin with metabolite profiling

Topical application of extracts frombaby aloe shoot (immature aloe with shoot length 50 cm) showing high levels of anthraquinone derivatives, suppressed ultraviolet (UV) B irradiation-induced skin damage, including increased epidermal thickness and matrix metalloproteinase-1 expression, decreased procollagen type I and involucrin expression, and changes in collagen fibers. Additionally, we applied mass spectrometry-based techniques with multivariate statistical analysis to UVB-exposed skin and showed that several types of skin metabolites, including amino acids, organic acids, nucleobases, fatty acids, sterols, carbohydrates, and glycerophospholipids, were altered in the epidermal and dermal layers by topical application of Aloe vera shoot extracts. In particular, four nucleobases (hypoxanthine, uridine, inosine, and cytidine) and cholesterol were significantly influenced by treatment with extracts from adult and baby aloe shoots, respectively. The alterations in skin metabolites induced by A. vera extracts in UVB-irradiated skin were generally greater in the epidermis than in the dermis. These metabolites represent biomarkers that indicate the effects of A. vera extracts on UVB-irradiated skin and will guide future studies. Our results suggest that the topical application of A. vera is capable of mitigating changes in the skin induced by UVB irradiation.

Abstract 3938: Localized synchrotron radiation affects serum cytokine levels and modulates gene expression in irradiated mouse skin and in skin distant from the irradiated site

Abstract Synchrotron radiation has great potential to improve cancer radiotherapy, a major cancer treatment received by about 50% cancer patients annually. A new synchrotron-based modality, microbeam radiotherapy (MRT), has shown promise for cancer treatment. MRT utilizes high intensity X-rays collimated to planar microbeams 25 μm-wide and with 200 μm period. MRT effectively ablates tumours but causes less damage to normal tissues compared to conventional broadbeam (BB) radiotherapy techniques. Little is known about the mechanisms underlying this remarkable result. We initiated a study of systemic (“abscopal”, “distant bystander”) effects1,2 of MRT and BB irradiation in C57BL/6J mice. Skin areas (2x2 and 8x8 mm) were irradiated with 10 or 40 Gy, and blood and skin samples were collected at 24 and 96 hours post-irradiation. Serum levels of pro-inflammatory cytokines known to be induced by radiation or to mediate the bystander effect, were measured. In parallel, gene expression was measured in irradiated and non-irradiated skin using real time PCR. Statistically significant changes were identified for known radiation responsive genes in both targeted and non-targeted dermal tissue after both BB and MRT treatments. Down-regulation of some genes in distant skin that were up-regulated at the site of irradiation were identified in an apparent contrasting response between these two sets of tissues. Also, the expression for some genes showed differences between MRT and BB-treated mice. MRT-specific bystander responses were also observed in distant tissue, including gene expression of TP53 for which the protein product has a fundamental role in cell fate. Levels of various cytokines in the serum were also altered in response to both BB and MRT. In some cases, the cytokine response was different for MRT compared to BB-treated samples which could potentially explain the benefits of MRT. These results advance the understanding of the biological responses to synchrotron-generated radiation and provide a potential mechanism for MRT.

Photoprotection of Buddleja cordata extract against UVB-induced skin damage in SKH-1 hairless mice.

BackgroundIn recent years, there has been considerable interest in using botanical agents to prevent skin damage resulting from solar UV-irradiation. Buddleja cordata is a plant that is known as “tepozan”. Some people in Mexico use the leaves of this plant to treat tumours, abscesses, sores and burns. The purpose of this study is to investigate the photoprotective properties of Buddleja cordata methanolic extract (BCME) against UVB-induced skin damage in SKH-1 hairless mice at the macroscopic and histological levels.MethodsBCME was characterised to determine its spectroscopic, chromatographic and antioxidant (DPPH, superoxide and hydroxyl radicals) properties. To conduct the photoprotection studies, BCME was applied topically to the skin of SKH-1 mice before acute exposure to UVB for 10 minutes. The murine skin samples were used for macroscopic and histological studies to assess tissue damage. Penetration of active components of BCME into stratum corneum on the dorsal area of mice was investigated in vivo by the tape stripping method. Moreover, genotoxicity of BCME was evaluated in a Vicia faba cell root micronucleus model.ResultsBCME displayed absorbance over the entire UVB spectrum, and its principal components included verbascoside and linarin. BCME exhibited antioxidant activity and significantly scavenged hydroxyl radicals. BCME reduced erythema, sunburn cell production, vessel congestion and epidermal thickening of UVB irradiated mouse skin. BCME penetrate the skin of mice. BCME did not exhibit genotoxic activity in the micronucleus test.ConclusionThe topical administration of BCME protected against acute UVB-induced damage in mouse SKH-1 skin, and our results suggest that BCME may potentially prevent photodamage.

Biological Effects of Femtosecond-Terahertz Pulses on C57BL/6 Mouse Skin

Biological Effects of Femtosecond-Terahertz Pulses on C57BL/6 Mouse Skin

Exposure to gamma-rays at the telogen phase of the hair cycle inhibits hair follicle regeneration at the anagen phase in mice

Purpose: The effects of ionizing radiations on somatic stem cells largely remain to be studied. Hair follicles are self-renewing structures that reconstitute themselves throughout the hair cycle, which is comprised of the following phases: Anagen (growth), catagen (regression) and telogen (resting), suggesting the presence of their own stem cells.Materials and methods: The whole bodies of C57BL/10JHir mice in the 1st telogen phase were irradiated with γ-rays. Mice were examined for effects on hair follicles, including their number, morphology and pigmentation in the 2nd anagen phase.Results: Decreased hair follicle density and induction of curved hair follicles were observed in the dermal skin of irradiated mice. In addition to these keratinocyte-derived anomalies, melanocyte-derived anomalies including white hair and hypopigmented hair bulbs were found. The decrease in hair follicle density and the increase in the frequency of hypopigmented hair bulbs were dependent on the dose of γ-rays.Conclusions: These results suggest that γ-rays damage stem cells and progenitors for keratinocytes and melanocytes, thereby affecting the structure and character of regenerated hair follicles. The density of hair follicles and pigment production in hair bulbs are established as criteria for the effects of γ-rays on the hair cycle.