Induction of dopamine D1 and D5 receptors in R28 cells by light exposures

Spectral and color temperature dependence of LED exposure on retinal damage and the protective effects of neohesperidin

PURPOSE

To investigate the effects of LEDs with different spectra and correlated color temperatures on the retina, as well as the protective role of neohesperidin(NHP).

METHODS

Sprague-Dawley (SD) rats and 661W cells were divided into four groups: 2700K conventional LED group (CL-2700K), 5000K conventional LED group (CL-5000K), 2700K full-spectrum LED group (FL-2700K) and 5000K full-spectrum LED group (FL-5000K). Retinal damage was detected using Hematoxylin and Eosin (HE) staining, while the expression of mitochondria-related autophagy proteins in retinas was determined through immunofluorescence. The CCK-8 assay, ROS detection, mitochondrial membrane potential assessment and Annexin V-FITC/PI staining were used to assess damage in 661W cell. RT-qPCR and Western blotting were employed to detect the expression of related genes and proteins.

RESULTS

After LED exposure, retinal tissue damage was observed in the rats. 661W cells exhibited upregulated levels of ROS, JC-1 monomer aggregation, and cell apoptosis. Notably, the FL-2700K exhibited the least severe damage. Intervention experiments revealed that 25 μM NHP reduced ROS levels and JC-1 aggregation,as well asmitigated apoptosis levels. Further studies indicated that NHP maintained mitochondrial autophagy at normal levels in 661W cells across all groups and reduced the mRNA expression of Crx and Arrestin-1.

CONCLUSIONS

2700K full-spectrum LEDs can mitigate photochemical damage in vivo and in vitro. NHP is a promising drug for treating photochemical damage.

Single-cell RNA sequencing of retina revealed novel transcriptional landscape in high myopia and underlying cell-type-specific mechanisms

High myopia is a leading cause of blindness worldwide with increasing prevalence. Retina percepts visual information and triggers myopia development, but the underlying etiology is not fully understood because of cellular heterogeneity. In this study, single-cell RNA sequencing analysis was performed on retinas of mouse highly myopic and control eyes to dissect the involvement of each cell type during high myopia progression. For highly myopic photoreceptors, Hk2 inhibition underlying metabolic remodeling from aerobic glycolysis toward oxidative phosphorylation and excessive oxidative stress was identified. Importantly, a novel Apoe + rod subpopulation was specifically identified in highly myopic retina. In retinal neurons of highly myopic eyes, neurodegeneration was generally discovered, and the imbalanced ON/OFF signaling driven by cone-bipolar cells and the downregulated dopamine receptors in amacrine cells were among the most predominant findings, indicating the aberrant light processing in highly myopic eyes. Besides, microglia exhibited elevated expression of cytokines and TGF-β receptors, suggesting enhanced responses to inflammation and the growth-promoting states involved in high myopia progression. Furthermore, cell-cell communication network revealed attenuated neuronal interactions and increased glial/vascular interactions in highly myopic retinas. In conclusion, this study outlines the transcriptional landscape of highly myopic retina, providing novel insights into high myopia development and prevention.

New epiretinal implant with integrated sensor chips for optical capturing shows a good biocompatibility profile in vitro and in vivo

BACKGROUND

Retinal degenerative diseases, e.g., retinitis pigmentosa, cause a severe decline of the visual function up to blindness. Treatment still remains difficult; however, implantation of retinal prostheses can help restoring vision. In this study, the biocompatibility and surgical feasibility of a newly developed epiretinal stimulator (OPTO-EPIRET) was investigated. The previously developed implant was extended by an integrated circuit-based optical capturing, which will enable the immediate conversion of the visual field into stimulation patterns to stimulate retinal ganglion cells.

RESULTS

The biocompatibility of the OPTO-EPIRET was investigated in vitro using the two different cell lines L-929 and R28. Direct and indirect contact were analyzed in terms of cell proliferation, cell viability, and gene expression. The surgical feasibility was initially tested by implanting the OPTO-EPIRET in cadaveric rabbit eyes. Afterwards, inactive devices were implanted in six rabbits for feasibility and biocompatibility testings in vivo. In follow-up controls (1-12 weeks post-surgery), the eyes were examined using fundoscopy and optical coherence tomography. After finalization, histological examination was performed to analyze the retinal structure. Regarding the in vitro biocompatibility, no significant influence on cell viability was detected (L929: < 1.3% dead cells; R-28: < 0.8% dead cells). The surgery, which comprised phacoemulsification, vitrectomy, and implantation of the OPTO-EPIRET through a 9-10 mm corneal incision, was successfully established. The implant was fixated with a retinal tack. Vitreal hemorrhage or retinal tearing occurred as main adverse effects. Transitional corneal edema caused difficulties in post-surgical imaging.

CONCLUSIONS

The OPTO-EPIRET stimulator showed a good biocompatibility profile in vitro. Furthermore, the implantation surgery was shown to be feasible. However, further design optimization steps are necessary to avoid intra- and postoperative complications. Overall, the OPTO-EPIRET will allow for a wide visual field and good visual acuity due to a high density of electrodes in the central retina.