Project description:The widely used white light-emitting diodes (LED) deliver higher levels of blue light than do conventional domestic light sources. The high intensity of blue component is the main source of concern about the health risks of LED with respect to their light-toxicity to the retina. White LED light with higher correlated color temperature (CCT) is more likely to cause retinal injury in mice, significantly reducing the number of ONL nuclei, however apoptosis pathway may not be the only mechanism. We used the Affymetrix GeneChip (Mouse Genome 430 2.0) to describe the different influence on gene expression of mouse retina under white LED light with different CCT.
Project description:In recent years, concerns have escalated regarding eye health problems arising from Light-emitting diode (LED), which emits high-energy blue light (BL), potentially causing corneal epithelial dysfunctions (CEpD). Nevertheless, the mechanisms underlying this damage remain poorly comprehended. This study endeavors to explore the specific mechanisms through which BL exposure induces CEpD. The study carried out diverse assays and treatments to investigate the toxicological effects of BL exposure. 48 hours (h) of 440 nm of BL exposure decreased the migration of human corneal epithelial cells (hCEpCs) while augmenting reactive oxygen species (ROS) production and apoptosis. RNA-Sequencing and bioinformatic analysis indicated that cellular oxidation and reduction equilibrium, wound healing, the positive regulation of the apoptotic process, and the Phosphoinositide 3-kinase (PI3K)/AKT pathway were significantly influenced by BL exposure. Treatment with N-acetylcysteine (NAC), a ROS scavenger, restored cell viability and AKT/S6 kinase (S6K) activation, suggesting the involvement of ROS in BL-induced damage. NAC also reversed BL-induced apoptosis and migration. Blocking AKT/S6K replicated detrimental effects, while pre-treatment with SC79 (SC), an AKT activator, alleviated the changes caused by BL exposure in hCEpCs. Furthermore, in mice, the combination of AKT inhibition and BL exposure led to CEpD. However, treatment with SC and NAC restored CEpD caused by BL exposure. These results imply that the regulation of the ROS/PI3K/AKT/S6K axis is implicated in BL-induced CEpD. Collectively, this study offers insights into the molecular mechanisms of BL-induced CEpD and proposes targeting the ROS/PI3K/AKT/S6K cascade as a potential therapeutic approach. The findings contribute to ocular health knowledge and establish the basis for developing interventions to safeguard the cornea from the detrimental effects of excessive BL exposure.
Project description:Electric light has enabled humans to conquer the night, but light exposure at night can disrupt the circadian timing system and is associated with a diverse range of health disorders. To provide adequate lighting for visual tasks without disrupting the human circadian timing system, a precise definition of circadian spectral sensitivity is required. Prior attempts to define the circadian spectral sensitivity curve have used short (≤90-min) monochromatic light exposures in dark-adapted human subjects or in vitro dark-adapted isolated retina or melanopsin. Several lines of evidence suggest that these dark-adapted circadian spectral sensitivity curves, in addition to 430- to 499-nm (blue) wavelength sensitivity, may include transient 400- to 429-nm (violet) and 500- to 560-nm (green) components mediated by cone- and rod-originated extrinsic inputs to intrinsically photosensitive retinal ganglion cells (ipRGCs), which decay over the first 2 h of extended light exposure. To test the hypothesis that the human circadian spectral sensitivity in light-adapted conditions may have a narrower, predominantly blue, sensitivity, we used 12-h continuous exposures of light-adapted healthy human subjects to 6 polychromatic white light-emitting diode (LED) light sources with diverse spectral power distributions at recommended workplace levels of illumination (540 lux) to determine their effect on the area under curve of the overnight (2000-0800 h) salivary melatonin. We derived a narrow steady-state human Circadian Potency spectral sensitivity curve with a peak at 477 nm and a full-width half-maximum of 438 to 493 nm. This light-adapted Circadian Potency spectral sensitivity permits the development of spectrally engineered LED light sources to minimize circadian disruption and address the health risks of light exposure at night in our 24/7 society, by alternating between daytime circadian stimulatory white light spectra and nocturnal circadian protective white light spectra.
Project description:To investigate light-regulated miRNAs in the human retina we photostimulated retinal organoids and found 51 light-regulated miRNAs that are significantly up- or down-regulated.
Project description:Polyamines play a pivotal role in plant growth and development by modulating metabolite levels and even regulating DNA methylation. To reveal novel insights into the intricate relationship among polyamines, metabolites and DNA methylation, the impact of exogenous putrescine on wheat was investigated at several levels. Since the outcome of putrescine treatment may vary depending on the light quality, the experiment was performed under both white and blue light. Metabolite profiling revealed distinct changes induced by blue light and/or putrescine. Blue light alone had increasing effects on several metabolites, but the effect of putrescine was dominant under blue light in most cases. Putrescine had a decreasing effect on some amino acids and the γ-glutamyl-cycle, while increasing effect on the TCA-cycle. Distinct changes in DNA methylation patterns were detected in response to blue light, putrescine or their combination. Blue light exerted strong effects on methylation, and putrescine application slightly could induce further changes. Putrescine had a higher impact under white as increased the leaf spermidine level, and parallel with this, a lower level of up-methylated genes involved in cellular processes, but a higher level of down-methylated genes involved in molecular function and biological processes occurred compared to the blue light.
Project description:It is a randomized controlled trial with tandem colonoscopy.Participants were randomized for use of either blue laser imaging or conventional White Light Colonoscopy on withdrawal method.comparison of detection and miss rates of BLI group Versus conventional White Light Colonoscopy.
Project description:Microarray analysis of murine retinal light damage reveals changes in iron regulatory, complement, and antioxidant genes in the neurosensory retina and isolated retinal pigment epithelium (RPE). With the advent of microarrays representing most of the transcriptome and techniques to obtain RNA from the isolated RPE monolayer, we have probed the response of the RPE and neurosensory retina (NSR) to light damage. Mice were exposed to 10,000 lux cool white fluorescent light for 18 hours and sacrificed 4 hours after photic injury. NSR and isolated RPE were collected, and RNA was isolated. DNA microarray hybridization was conducted as described in the Affymetrix GeneChip Expression Analysis Technical Manual. Microarray analysis was performed using probe intensity data derived from the Mouse Gene 1.0 ST Array. For the genes of interest, confirmation of gene expression was done using quantitative real-time PCR. Immunofluorescence assessed protein levels and localization.