Micronuclei as an indicator of genotoxic change in epithelial cells of buccal mucosa after panoramic radiographs.

BACKGROUND: The radiation released at the time of dental panoramic radiographs causes genotoxic and cytotoxic effects on epithelial cells. OBJECTIVE: This research aimed to evaluate the changes in the frequencies of micronucleated cells in patients' buccal epithelial cells following dental panoramic radiography. METHODS: 74 patients were recruited for the study who were advised for panoramic radiographs. Using a wooden spatula, the buccal epithelial cells were scraped from both cheeks before to panoramic radiation exposure and ten days after the panoramic radiation exposure. Giemsa stain was used to stain the cells, and 500 cells were scored on a slide to determine the frequency of micronuclei. To determine the difference between the frequency of micronuclei before and after radiation exposure, a paired t-test was used in the statistical analysis. RESULTS: The proportion of micronuclei cells was 0.11% before radiation exposure and 0.57% following radiation exposure after 10 days. A statistically significant increase in the frequencies of micronuclei was noted after radiation exposure values. CONCLUSION: This study revealed the genotoxicity of epithelial cells with dental panoramic radiation exposure. It is advised to reduce the use of such radiographs and to use only when there is no other diagnostic tool that is helpful or when absolutely essential.

Modeling Radiation-Induced Epithelial Cell Injury in Murine Three-Dimensional Esophageal Organoids.

Esophageal squamous cell carcinoma (ESCC) is a deadly consequence of radiation exposure to the esophagus. ESCC arises from esophageal epithelial cells that undergo malignant transformation and features a perturbed squamous cell differentiation program. Understanding the dose- and radiation quality-dependence of the esophageal epithelium response to radiation may provide insights into the ability of radiation to promote ESCC. We have explored factors that may play a role in esophageal epithelial radiosensitivity and their potential relationship to ESCC risk. We have utilized a murine three-dimensional (3D) organoid model that recapitulates the morphology and functions of the stratified squamous epithelium of the esophagus to study persistent dose- and radiation quality-dependent changes. Interestingly, although high-linear energy transfer (LET) Fe ion exposure induced a more intense and persistent alteration of squamous differentiation and 53BP1 DNA damage foci levels as compared to Cs, the MAPK/SAPK stress pathway signaling showed similar altered levels for most phospho-proteins with both radiation qualities. In addition, the lower dose of high-LET exposure also revealed nearly the same degree of morphological changes, even though only ~36% of the cells were predicted to be hit at the lower 0.1 Gy dose, suggesting that a bystander effect may be induced. Although p38 and ERK/MAPK revealed the highest levels following high-LET exposure, the findings reveal that even a low dose (0.1 Gy) of both radiation qualities can elicit a persistent stress signaling response that may critically impact the differentiation gradient of the esophageal epithelium, providing novel insights into the pathogenesis of radiation-induced esophageal injury and early stage esophageal carcinogenesis.

Photobiomodulation of Gingival Cells Challenged with Viable Oral Microbes.

The oral cavity, a unique ecosystem harboring diverse microorganisms, maintains health through a balanced microflora. Disruption may lead to disease, emphasizing the protective role of gingival epithelial cells (GECs) in preventing harm from pathogenic oral microbes. Shifting GECs' response from proinflammatory to antimicrobial could be a novel strategy for periodontitis. Photobiomodulation therapy (PBMT), a nonpharmacologic host modulatory approach, is considered an alternative to drugs. While the host cell response induced by a single type of pathogen-associated molecular patterns (PAMPs) was widely studied, this model does not address the cellular response to intact microbes that exhibit multiple PAMPs that might modulate the response. Inspired by this, we developed an in vitro model that simulates direct interactions between host cells and intact pathogens and evaluated the effect of PBMT on the response of human gingival keratinocytes (HGKs) to challenge viable oral microbes at both the cellular and molecular levels. Our data demonstrated that LED pretreatment on microbially challenged HGKs with specific continuous wavelengths (red: 615 nm; near-infrared: 880 nm) induced the production of various antimicrobial peptides, enhanced cell viability and proliferation, promoted reactive oxygen species scavenging, and down-modulated proinflammatory activity. The data also suggest a potential explanation regarding the superior efficacy of near-infrared light treatment compared with red light in enhancing antimicrobial activity and reducing cellular inflammation of HGKs. Taken together, the findings suggest that PBMT enhances the overall barrier function of gingival epithelium while minimizing inflammation-mediated breakdown of the underlying structures.

The impact of dose rate on responses of human lens epithelial cells to ionizing irradiation.

The knowledge on responses of human lens epithelial cells (HLECs) to ionizing radiation exposure is important to understand mechanisms of radiation cataracts that are of concern in the field of radiation protection and radiation therapy. However, biological effects in HLECs following protracted exposure have not yet fully been explored. Here, we investigated the temporal kinetics of γ-H2AX foci as a marker for DNA double-strand breaks (DSBs) and cell survival in HLECs after exposure to photon beams at various dose rates (i.e., 150 kVp X-rays at 1.82, 0.1, and 0.033 Gy/min, and 137Cs γ-rays at 0.00461 Gy/min (27.7 cGy/h) and 0.00081 Gy/min (4.9 cGy/h)), compared to those in human lung fibroblasts (WI-38). In parallel, we quantified the recovery for DSBs and cell survival using a biophysical model. The study revealed that HLECs have a lower DSB repair rate than WI-38 cells. There is no significant impact of dose rate on cell survival in both cell lines in the dose-rate range of 0.033-1.82 Gy/min. In contrast, the experimental residual γ-H2AX foci showed inverse dose rate effects (IDREs) compared to the model prediction, highlighting the importance of the IDREs in evaluating radiation effects on the ocular lens.

Spatially modulated ablation driven by chaotic attractors in human lung epithelial cancer cells.

A significant modification in photoinduced energy transfer in cancer cells is reported by the assistance of a dynamic modulation of the beam size of laser irradiation. Human lung epithelial cancer cells in monolayer form were studied. In contrast to the quantum and thermal ablation effect promoted by a standard focused Gaussian beam, a spatially modulated beam can caused around 15% of decrease in the ablation threshold and formation of a ring-shaped distribution of the photothermal transfer effect. Optical irradiation was conducted in A549 cells by a 532 nm single-beam emerging from a Nd:YVO4 system. Ablation effects derived from spatially modulated convergent waves were controlled by an electrically focus-tunable lens. The proposed chaotic behavior of the spatial modulation followed an Arneodo chaotic oscillator. Fractional dynamic thermal transport was analyzed in order to describe photoenergy in propagation through the samples. Immediate applications of chaos theory for developing phototechnology devices driving biological functions or phototherapy treatments can be considered.

Blue light induced ferroptosis via STAT3/GPX4/SLC7A11/FTH1 in conjunctiva epithelium in vivo and in vitro.

The prevalence of Light-emitting diodes (LEDs) has exposed us to an excessive amount of blue light (BL) which causes various ophthalmic diseases. Previous studies have shown that conjunctiva is vulnerable to BL. In this study, we aimed to investigate the underlying mechanism of BL-induced injury in conjunctiva. We placed C57BL/6 mice and human conjunctival epithelial cell lines (HCECs) under BL (440 nm ± 15 nm, 0.2 mW/cm2) to establish a BL injury model in vivo and in vitro. Immunohistochemistry and MDA assay were used to identify lipid peroxidation (LPO) in vivo. HE staining was applied to detect morphological damage of conjunctival epithelium. DCFH-DA, C11-BODIPY 581/591, Calcein-AM, and FeRhoNox™-1 probes were performed to identify ferroptosis levels in vitro. Real-time qPCR and Western blotting techniques were employed to uncover signaling pathways of blue light-induced ferroptosis. Our findings demonstrated that BL affected tear film instability and induced conjunctival epithelium injury in vivo. Ferrostatin-1 significantly alleviated blue light-induced ferroptosis in vivo and in vitro. BL downregulates the levels of solute carrier family 7 member 11 (SLC7A11), Ferritin heavy chain (FTH1), and glutathione peroxidase (GPX4) by inhibiting the activation and translocation of the Signal transducer and activator of transcription 3 (STAT3) from inducing Fe2+ burst, ROS and LPO accumulation, ultimately resulting in ferroptosis. This study will offer new insight into BL-induced conjunctival injury and LED-induced dry eye.

Phenotypic and transcriptional changes in lens epithelial cells following acute and fractionated ionizing radiation exposure.

PURPOSE: Exposure to ionizing radiation is one of the known risk factors for the development of lens opacities. It is believed that radiation interactions with lens epithelial cells (LEC) are the underlying cause of cataract development, however, the exact mechanisms have yet to be identified. The aim of this study was to investigate how different radiation dose and fractionation impact normal LEC function. MATERIALS AND METHODS: A human derived LEC cell line (HLE-B3) was exposed to a single acute x-ray dose (0.25 Gy) and 6 fractionated doses (total dose of 0.05, 0.1, 0.25, 0.5, 1, and 2 Gy divided over 5 equal fractions). LEC were examined for proliferation using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and migration using a Boyden chamber assay at various time points (0.25, 0.5, 1, 2, 4, 7, 9, 11, and 14 d) post-irradiation. Transcriptomic analysis through RNA sequencing was also performed to identify differentially expressed genes and regulatory networks in cells following 4 different acute exposures and 1 fractionated exposure. RESULTS: Exposure to an acute dose of 0.25 Gy significantly increased proliferation and migration rates, peaking at 7 d post irradiation (20% and 240% greater than controls, respectively), before returning to baseline levels by day 14. Fractionated exposures had minimal effects up to a dose of 0.5 Gy, but significantly reduced proliferation and migration after 1 and 2 Gy by up to 50%. The largest transcriptional response occurred 12 h after an acute 0.25 Gy dose, with 362 genes up-regulated and 288 genes down-regulated. A unique panel of differentially expressed genes was observed between moderate versus high dose exposures, suggesting a dose-dependent transcriptional response in LEC that is more pronounced at lower doses. Gene ontology and upstream regulator analysis identified multiple biological processes and molecular functions implicated in the radiation response, in particular differentiation, motility, receptor/ligand binding, cell signaling and epithelial-mesenchymal cell transition. CONCLUSIONS: Overall, this research provides novel insights into the dose and fractionation effects on functional changes and transcriptional regulatory networks in LEC, furthering our understanding of the mechanisms behind radiation induced cataracts.

Dependence of Induced Biological Damage on the Energy Distribution and Intensity of Clinical Intra-Operative Radiotherapy Electron Beams.

The survival fraction of epithelial HaCaT cells was analysed to assess the biological damage caused by intraoperative radiotherapy electron beams with varying energy spectra and intensities. These conditions were achieved by irradiating the cells at different depths in water using nominal 6 MeV electron beams while consistently delivering a dose of 5 Gy to the cell layer. Furthermore, a Monte Carlo simulation of the entire irradiation procedure was performed to evaluate the molecular damage in terms of molecular dissociations induced by the radiation. A significant agreement was found between the molecular damage predicted by the simulation and the damage derived from the analysis of the survival fraction. In both cases, a linear relationship was evident, indicating a clear tendency for increased damage as the averaged incident electron energy and intensity decreased for a constant absorbed dose, lowering the dose rate. This trend suggests that the radiation may have a more pronounced impact on surrounding healthy tissues than initially anticipated. However, it is crucial to conduct additional experiments with different target geometries to confirm this tendency and quantify the extent of this effect.

Ferulic Acid Protects Human Lens Epithelial Cells against Ionizing Radiation-Induced Oxidative Damage by Activating Nrf2/HO-1 Signal Pathway.

Ionizing radiation- (IR-) induced oxidative stress has been recognized as an important mediator of apoptosis in lens epithelial cells (LECs) and also plays an important role in the pathogenesis of IR-induced cataract. Ferulic acid (FA), a phenolic phytochemical found in many traditional Chinese medicine, has potent radioprotective and antioxidative properties via activating nuclear factor erythroid 2-related factor 2 (Nrf2) signal pathway. The goals of this study were to determine the protective effect of FA against IR-induced oxidative damage on human lens epithelial cells (HLECs) and to elucidate the role of Nrf2 signal pathway. HLECs were subjected to 4 Gy X-ray radiation with or without pretreatment of FA. It was found that FA pretreatment protected HLECs against IR-induced cell apoptosis and reduced levels of ROS and MDA caused by radiation in a dose-dependent manner. IR-dependent attenuated activities of antioxidant enzymes (SOD, CAT, and GPx) and decreased ratio of reduced GSH/GSSG were increased by pretreatment of FA. FA inhibited IR-induced increase of Bax and cleaved caspase-3 and the decrease of Bcl-2 in a dose-dependent manner. Furthermore, FA provoked Nrf2 nuclear translocation and upregulated mRNA and protein expressions of HO-1 in a dose-dependent manner. These findings indicated that FA could effectively protect HLECs against IR-induced apoptosis by activating Nrf2 signal pathway to inhibit oxidative stress, which suggested that FA might have a therapeutic potential in the prevention and alleviation of IR-induced cataract.

Epigallocatechin gallate enhances human lens epithelial cell survival after UVB irradiation via the mitochondrial signaling pathway.

The aim of the present study was to explore the mechanism underlying the ultraviolet B (UVB) irradiation­induced apoptosis of human lens epithelial cells (HLECs), and to investigate the protective effect of epigallocatechin gallate (EGCG) against the UVB­induced apoptosis of HLECs. HLECs were exposed to different concentrations of EGCG plus UVB (30 mJ/cm2). Cell viability was determined using the MTT assay. Furthermore, mitochondrial membrane potential (Δψm) and apoptosis were assessed by flow cytometry with JC­1 and Annexin V/PI staining, respectively. Moreover, the activities of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH­Px), as well as the levels of GSH, hydrogen peroxide (H2O2) and hydroxyl free radicals were determined using biochemical assay techniques. Reverse transcription­quantitative PCR and western blotting were used to detect the mRNA and protein expression levels of Bcl­2, Bax, cytochrome c, caspase­9 and caspase­3, respectively. The results revealed that UVB irradiation reduced the Δψm of HLECs and induced apoptosis. Notably, EGCG significantly attenuated the generation of H2O2 and hydroxyl free radicals caused by UVB irradiation in HLECs, and significantly increased CAT, SOD and GSH­Px activities, however, the GSH levels were not significantly increased. EGCG also reduced UVB­stimulated Bax, cytochrome c, caspase­9 and caspase­3 expression, and elevated Bcl­2 expression, suggesting that EGCG may possess free radical­scavenging properties, thus increasing cell viability. In conclusion, EGCG may be able to protect against UVB­induced HLECs apoptosis through the mitochondria­mediated apoptotic signaling pathway, indicating its potential application in clinical practice.

Ultraviolet-A light increases mitochondrial anti-viral signaling protein in confluent human tracheal cells via cell-cell signaling.

Mitochondrial antiviral signaling (MAVS) protein mediates innate antiviral responses, including responses to certain coronaviruses such as severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). We have previously shown that ultraviolet-A (UVA) therapy can prevent virus-induced cell death in human ciliated tracheal epithelial cells (HTEpC) infected with coronavirus-229E (CoV-229E), and results in increased intracellular levels of MAVS. In this study, we explored the mechanisms by which UVA light can activate MAVS, and whether local UVA light application can activate MAVS at locations distant from the light source (e.g. via cell-to-cell communication). MAVS levels were compared in HTEpC exposed to 2 mW/cm2 narrow band (NB)-UVA for 20 min and in unexposed controls at 30-40% and at 100% confluency, and in unexposed HTEpC treated with supernatants or lysates from UVA-exposed cells or from unexposed controls. MAVS was also assessed in different sections of confluent monolayer plates where only one section was exposed to NB-UVA. Our results showed that UVA increases the expression of MAVS protein. Further, cells in a confluent monolayer exposed to UVA conferred an elevation in MAVS in cells adjacent to the exposed section, and also in cells in the most distant sections which were not exposed to UVA. In this study, human ciliated tracheal epithelial cells exposed to UVA demonstrate increased MAVS protein, and also appear to transmit this influence to confluent cells not exposed to UVA, likely via cell-cell signaling.

Circular RNA erythrocyte membrane protein band 4.1 assuages ultraviolet irradiation-induced apoptosis of lens epithelial cells by stimulating 5'-bisphosphate nucleotidase 1 in a miR-24-3p-dependent manner.

Apoptosis of lens epithelial cells contributed to the formation of age-related cataract (ARC), and previous data revealed that circular RNA (circRNA) was responsible for the underneath mechanism. The study was organized to explore the role of circular RNA erythrocyte membrane protein band 4.1 (circ_EPB41) in ultraviolet (UV) irradiation-induced apoptosis of lens epithelial cells. SRA01/04 cells were irradiated with UV to mimic the ARC cell model. The RNA levels of circ_EPB41, microRNA-24-3p (miR-24-3p), and 3'(2'), 5'-bisphosphate nucleotidase 1 (BPNT1) were detected by quantitative real-time polymerase chain reaction. Protein expression was checked by western blot. 5-Ethynyl-29-deoxyuridine, 3-(4,5-Dimethylthazol-2-yl)-2,5-diphenyltetrazolium bromide and DNA content quantitation assays were performed to investigate cell proliferation. Flow cytometry was conducted to analyze cell apoptosis. Dual-luciferase reporter assay was implemented to confirm the interaction among circ_EPB41, miR-24-3p, and BPNT1. Our data showed that circ_EPB41 and BPNT1 expression were downregulated in ARC tissues and UV-irradiated SRA01/04 cells as compared with normal anterior lens capsules and untreated SRA01/04 cells. Circ_EPB41 overexpression ameliorated the effects of UV irradiation on the proliferation and apoptosis of SRA01/04 cells. Besides, miR-24-3p, a target miRNA of circ_EPB41, attenuated circ_EPB41 introduction-mediated proliferation, and apoptosis of UV-irradiated SRA01/04 cells. MiR-24-3p regulated UV irradiation-induced effects by targeting BPNT1. Importantly, it was found that circ_EPB41 stimulated BPNT1 production by miR-24-3p. Taken together, the enforced expression of circ_EPB41 ameliorated UV irradiation-induced apoptosis of lens epithelial cells by miR-24-3p/BPNT1 pathway, providing us with a potential target for the therapy of UV-caused ARC.

Short-wavelength blue light contributes to the pyroptosis of human lens epithelial cells (hLECs).

PURPOSE: The purpose of this study is to examine the effect of short-wavelength blue light (SWBL) on cultured human lens epithelial cells (hLECs). The pathogenesis of cataracts after SWBL exposure is discussed. METHODS: HLE-B3 hLECs were randomly divided into 3 groups: the NC group, which was grown in a dark incubator; the acetyl (Ac)-Tyr-Val-Ala-Asp-chloromethyl ketone (AC-YVAD-CMK) treatment group; and the SWBL exposure group. After SWBL (2500 lux) irradiation (for 8, 16, 24, and 32 h), caspase-1 and gasdermin D (GSDMD) expression levels in HLE-B3 hLECs were examined using ELISA, immunofluorescence staining, and Western blotting analyses. Double-positive staining of hLECs for activated and inhibited caspase-1 was used to determine pyroptosis in HLE-B3 hLECs. RESULTS: SWBL led to hLEC death, but a caspase-1 inhibitor suppressed cell death. The flow cytometry results also confirmed the dose-dependent effect of SWBL irradiation on the pyroptotic death of hLECs. Caspase-1 and GSDMD expression levels in all hLEC groups changed with blue light exposure times (8, 16, 24, and 32 h) and were higher in the AC-YVAD-CMK and SWBL exposure groups than in the NC group. The immunofluorescence results revealed higher GSDMD-N expression in the cell membrane of both the AC-YVAD-CMK and SWBL exposure groups than in the NC group. CONCLUSIONS: Based on the data, SWBL induces pyroptotic programmed cell death by activating the GSDMD signalling axis in HLE-B3 hLECs. These results provide new insights into the exploitation of new candidates for the prevention of cataracts.

Dynamic changes in and time sequence of ultraviolet B-induced apoptosis in rat corneal epithelial cells.

PURPOSE: To systematically examine the dynamic changes and time sequence in corneal epithelial cell apoptosis after excessive ultraviolet B irradiation. METHODS: Ultraviolet B (144 mJ/cm2) was used to irradiate rat corneal epithelial cells for 2 h. Cell morphology was observed on differential interference contrast microscopy, and the numbers of the different kinds of apoptotic cells were counted using the ImageJ software. Cell viability was measured with the 3-(4,5-dimethyl-2-thiazolyl)-2,5- diphenyl-2-H-tetrazolium bromide method. Cell apoptotic rate and loss of mitochondrial membrane potential were detected using flow cytometric analyses. The expression levels of 3 apoptotic genes were measured with real-time quantitative polymerase chain reaction at different time points within 0-24 h after irradiation. RESULTS: After 144-mJ/cm2 ultraviolet B irradiation for 2 h, the expression levels of caspase-8 and Bax were highest at 0 h; furthermore, the mitochondrial membrane potential decreased at 0 h and remained constant for 6 h in a subsequent culture. At 6 h, caspase-3 was activated. The decrease in cell viability and increase in apoptotic rate peaked at 6 h. The caspase-3 expression level decreased within 12-24 h, which led to a decline in apoptotic rate and change in apoptotic stage. CONCLUSIONS: The corneal epithelial cells exhibited rapid apoptosis after ultraviolet B irradiation, which was associated with both extrinsic and intrinsic pathways.

Deficiency of heat shock factor 4 promotes lens epithelial cell senescence through upregulating p21cip1 expression.

Genetic mutations in heat shock factor 4 (Hsf4) is associated with both congenital and age-related cataracts. Hsf4 regulates lens development through its ability to both activate and inhibit transcription. Previous studies suggested Hsf4 is involved in modulating cellular senescence depending on p21cip1 and p27 kip1 expression in MEF cells. Here, we found that Hsf4 acts as a suppressor of p21cip1 expression and plays an anti-senescence role during lens development. Knocking out Hsf4 facilitated UVB-induced cellular senescence in mouse lens epithelial cells (mLECs). p21cip1 was upregulated at both the mRNA and protein levels in HSF4-/- mLECs under control and UVB-treated conditions, and knockdown of p21cip1 by siRNA alleviated UVB-induced cellular senescence. HSF4 directly bound to the p21cip1 promoter and increased H3K27m3 levels at the p21cip1 proximal promoter region by recruiting the methyltransferase EZH2. In animal models, p21cip1 was gradually upregulated in wild-type mouse lenses with increasing age, while Hsf4 levels decreased. We generated a Hsf4 mutant mice line (Hsf4del-42) which displayed obvious congenital cataract phenotype. The expression of p21cip1 and senescence-associated cytokines were induced in the cataractous lenses of Hsf4del-42 mice. H3K27m3 and EZH2 levels decreased in p21cip1 promoters in the lenses of Hsf4del-42 mice. The SA-ß-Gal activities were positive in lens epithelia of aged Hsf4null zebrafish compared to wild-type lenses. p21cip1 and senescence-associated cytokines levels were also upregulated in lenses of Hsf4null zebrafish. Accordingly, we propose that HSF4 plays a protective role in lens epithelial cells against cellular senescence during lens development and aging, partly by fine-tuning p21cip1 expression.

Expression of an X-Ray Irradiated EGFP-Expressing Plasmid Transfected into Nonirradiated Human Cells.

To investigate the repairability of X-ray induced DNA damage, particularly non-double-strand breaks in living cells, enhanced green fluorescent protein (EGFP)-expressing plasmids X-ray irradiated and then transfected into nonirradiated human cells, MCF7 and MCF10A. Live-cell imaging of EGFP fluorescence was performed to measure the efficiency of plasmid repair in cells. The number of EGFP-expressing cells significantly decreased with increasing X-ray dose for both cell lines. The obtained kinetic curves of EGFP expression indicating plasmid repair were quantitatively compared against algebraically calculated ones based on the values of the transfected plasmids that had been treated with nicking or restriction enzymes. Then, assuming a Poisson distribution of single-strand breaks (SSBs), the number of cells carrying these nicked plasmids that could express EGFP were estimated. Our experimental results revealed considerably fewer cells expressing EGFP compared to the expected values we had calculated. These results suggest that the lower proportion of cells expressing EGFP as a measure of plasmid repair was due not only to the complex chemical structures of termini created by SSBs compared to those created by enzyme treatments, but also that base lesions or AP sites proximately arising at the strand-break termini might compromise EGFP expression. These results emphasize that radiation-induced DNA breaks are less repairable than enzymatically induced DNA breaks, which is not apparent when using conventional gel electrophoresis assays of plasmid DNA.

UV Effect on Human Anterior Lens Capsule Macro-Molecular Composition Studied by Synchrotron-Based FTIR Micro-Spectroscopy.

Ultraviolet (UV) irradiation is an important risk factor in cataractogenesis. Lens epithelial cells (LECs), which are a highly metabolically active part of the lens, play an important role in UV-induced cataractogenesis. The purpose of this study was to characterize cell compounds such as nucleic acids, proteins, and lipids in human UV C-irradiated anterior lens capsules (LCs) with LECs, as well as to compare them with the control, non-irradiated LCs of patients without cataract, by using synchrotron radiation-based Fourier transform infrared (SR-FTIR) micro-spectroscopy. In order to understand the effect of the UV C on the LC bio-macromolecules in a context of cataractogenesis, we used the SR-FTIR micro-spectroscopy setup installed on the beamline MIRAS at the Spanish synchrotron light source ALBA, where measurements were set to achieve a single-cell resolution with high spectral stability and high photon flux. UV C irradiation of LCs resulted in a significant effect on protein conformation with protein formation of intramolecular parallel ß-sheet structure, lower phosphate and carboxyl bands in fatty acids and amino acids, and oxidative stress markers with significant increase of lipid peroxidation and diminishment of the asymmetric CH3 band.

Modulation of aqueous humor melatonin levels by yellow-filter and its protective effect on lens.

Melatonin is mainly secreted by the pineal gland, and it is also produced by various ocular structures such as the lens. It has been recently demonstrated that melatonin ocular synthesis can be induced by blocking the blue component of white light by means of filters. Melatonin exhibits antioxidant properties that can be useful to face light-induced oxidative stress as well as oxidative events associated to ocular pathologies like cataracts. Moreover, as oxidative stress is a main event in cataract development, changes in melatonin levels could happen and be relevant in the progression of this pathology, a subject that remains uncertain. The goal of this work was to analyze the ability of a short wavelength light blocking (yellow) filter to modulate endogenous melatonin concentration and the antioxidant and cytoprotective actions induced by yellow filter's use in lens. Furthermore, we evaluated the potential changes in aqueous humor melatonin concentration from patients with cataracts. In human lens epithelial cells, white light-emitting diode (LED) light challenge reduced melatonin secretion, protein levels of the enzymes involved in melatonin synthesis (hydroxyindole-O-methyltransferase and unphosphorylated and phosphorylated forms of arylalkylamine N-acetyltransferase) and cell viability whereas increased reactive oxygen species production. Yellow filter exposure precluded melatonin secretion reduction and protected cells from oxidative damage. Consistent with cataract patient's results, significantly lower levels of melatonin were observed in aqueous humor of alloxan-induced diabetic cataract rabbits as compared to those of control rabbits. In contrast, aqueous humor melatonin levels of diabetic cataract animals maintaining in cages covered with a yellow filter resembled control values. This recovery seems to be mediated by the induction of melatonin biosynthetic enzymes protein expression. Yellow filter also preserved Nrf2 lens protein expression and superoxide dismutase protein levels and activity in diabetic animals. Modulation of endogenous ocular melatonin concentration using blocking filters might be a promising approach to prevent premature lens opacification.

Synthesis and radioprotective effects of novel hybrid compounds containing edaravone analogue and 3-n-butylphthalide ring-opening derivatives.

As the potential risk of radiation exposure is increasing, radioprotectors studies are gaining importance. In this study, novel hybrid compounds containing edaravone analogue and 3-n-butylphthalide ring-opening derivatives were synthesized, and their radioprotective effects were evaluated. Among these, compound 10a displayed the highest radioprotective activity in IEC-6 and HFL-1 cells. Its oral administration increased the survival rates of irradiated mice and alleviated total body irradiation (TBI)-induced hematopoietic damage by mitigating myelosuppression and improving hematopoietic stem/progenitor cell frequencies. Furthermore, 10a treatment prevented abdominal irradiation (ABI)-induced structural damage to the small intestine. Experiment results demonstrated that 10a increased the number of Lgr5+ intestinal stem cells, lysozyme+ Paneth cells and Ki67+ transient amplifying cells, and reduced apoptosis of the intestinal epithelium cells in irradiated mice. Moreover, in vitro and in vivo studies demonstrated that the radioprotective activity of 10a is associated to the reduction of oxidative stress and the inhibition of DNA damage. Furthermore, compound 10a downregulated the expressions of p53, Bax, caspase-9 and caspase-3, and upregulated the expression of Bcl-2, suggesting that it could prevent irradiation-induced intestinal damage through the p53-dependent apoptotic pathway. Collectively, these findings demonstrate that 10a is beneficial for the prevention of radiation damage and has the potential to be a radioprotector.

Fabrication of Submicro-Nano Structures on Polyetheretherketone Surface by Femtosecond Laser for Exciting Cellular Responses of MC3T3-E1 Cells/Gingival Epithelial Cells.

PURPOSE: Polyetheretherketone (PEEK) exhibits high mechanical strengths and outstanding biocompatibility but biological inertness that does not excite the cell responses and stimulate bone formation. The objective of this study was to construct submicro-nano structures on PEEK by femtosecond laser (FSL) for exciting the responses of MC3T3-E1 cells and gingival epithelial (GE) cells, which induce regeneration of bone/gingival tissues for long-term stability of dental implants. MATERIALS AND METHODS: In this study, submicro-nano structures were created on PEEK surface by FSL with power of 80 mW (80FPK) and 160 mW (160FPK). RESULTS: Compared with PEEK, both 80FPK and 160FPK with submicro-nano structures exhibited elevated surface performances (hydrophilicity, surface energy, roughness and protein absorption). Furthermore, in comparison with 80FPK, 160FPK further enhanced the surface performances. In addition, compared with PEEK, both 80FPK and 160FPK significantly excited not only the responses (adhesion, proliferation, alkaline phosphatase [ALP] activity and osteogenic gene expression) of MC3T3-E1 cells but also responses (adhesion as well as proliferation) of GE cells of human in vitro. Moreover, in comparison with 80FPK, 160FPK further enhanced the responses of MC3T3-E1 cells/GE cells. CONCLUSION: FSL created submicro-nano structures on PEEK with elevated surface performances, which played crucial roles in exciting the responses of MC3T3-E1 cells/GE cells. Consequently, 160FPK with elevated surface performances and outstanding cytocompatibility would have enormous potential as an implant for dental replacement.