Retinitis pigmentosa is a hereditary retinal disease that affects rod and cone photoreceptors,leading to progressive photoreceptor loss.Previous research supports the beneficial effect of electrical stimulation on pho...Retinitis pigmentosa is a hereditary retinal disease that affects rod and cone photoreceptors,leading to progressive photoreceptor loss.Previous research supports the beneficial effect of electrical stimulation on photoreceptor survival.This study aims to identify the most effective electrical stimulation parameters and functional advantages of transcorneal electrical stimulation(tcES)in mice affected by inherited retinal degeneration.Additionally,the study seeked to analyze the electric field that reaches the retina in both eyes in mice and post-mortem humans.In this study,we recorded waveforms and voltages directed to the retina during transcorneal electrical stimulation in C57BL/6J mice using an intraocular needle probe with rectangular,sine,and ramp waveforms.To investigate the functional effects of electrical stimulation on photoreceptors,we used human retinal explant cultures and rhodopsin knockout(Rho^(-/-))mice,demonstrating progressive photoreceptor degeneration with age.Human retinal explants isolated from the donors’eyes were then subjected to electrical stimulation and cultured for 48 hours to simulate the neurodegenerative environment in vitro.Photoreceptor density was evaluated by rhodopsin immunolabeling.In vivo Rho^(-/-)mice were subjected to two 5-day series of daily transcorneal electrical stimulation using rectangular and ramp waveforms.Retinal function and visual perception of mice were evaluated by electroretinography and optomotor response(OMR),respectively.Immunolabeling was used to assess the morphological and biochemical changes of the photoreceptor and bipolar cells in mouse retinas.Oscilloscope recordings indicated effective delivery of rectangular,sine,and ramp waveforms to the retina by transcorneal electrical stimulation,of which the ramp waveform required the lowest voltage.Evaluation of the total conductive resistance of the post-mortem human compared to the mouse eyes indicated higher cornea-to-retina resistance in human eyes.The temperature recordings during and after electrical stimulation indicated no significant temperature change in vivo and only a subtle temperature increase in vitro(~0.5-1.5°C).Electrical stimulation increased photoreceptor survival in human retinal explant cultures,particularly at the ramp waveform.Transcorneal electrical stimulation(rectangular+ramp)waveforms significantly improved the survival and function of S and M-cones and enhanced visual acuity based on the optomotor response results.Histology and immunolabeling demonstrated increased photoreceptor survival,improved outer nuclear layer thickness,and increased bipolar cell sprouting in Rho^(-/-)mice.These results indicate that transcorneal electrical stimulation effectively delivers the electrical field to the retina,improves photoreceptor survival in both human and mouse retinas,and increases visual function in Rho^(-/-)mice.Combined rectangular and ramp waveform stimulation can promote photoreceptor survival in a minimally invasive fashion.展开更多
Streptozotocin(STZ)-induced type I diabetes mellitus(DM)models have been pivotal in diabetes research due to their ability to mimic the insulin-dependent hyperglyce-mia akin to human type I diabetes.However,these mode...Streptozotocin(STZ)-induced type I diabetes mellitus(DM)models have been pivotal in diabetes research due to their ability to mimic the insulin-dependent hyperglyce-mia akin to human type I diabetes.However,these models often suffer from poor induction rates and low survival post-STZ induction,especially in long-term experi-ments,necessitating insulin supplementation,which introduces additional variables to experiments.To address this,we present a novel modification to the STZ-induced DM model in C57BL/6J mice to improve survival rates without insulin supplemen-tation.Our method involves non-fasting,low-dose STZ injections dissolved in pH-neutral phosphate buffer saline instead of acidic sodium citrate buffer,administered over 5 days.We observed hyperglycemia induction in 94.28%of mice within a week post-injection,with stable high blood glucose levels,stable body weight,and minimal mortality up to 21 weeks.Notably,omitting 10%sucrose in water and fasting did not affect hyperglycemia induction.Our findings suggest that the modified protocol not only decreases the experimental effort of the researchers,but reduces animal stress and mortality,thus enhancing experimental outcomes and animal welfare.By opti-mizing the STZ-induced DM model in C57BL/6J mice,our study provides a valuable resource for researchers aiming to study diabetes and its complications while mini-mizing experimental variability and animal usage.展开更多
The cornea is an avascular,transparent tissue that is essential for visual function.Any disturbance to the corneal transparency will result in a severe vision loss.Due to the avascular nature,the cornea acquires most ...The cornea is an avascular,transparent tissue that is essential for visual function.Any disturbance to the corneal transparency will result in a severe vision loss.Due to the avascular nature,the cornea acquires most of the oxygen supply directly or indirectly from the atmosphere.Corneal tissue hypoxia has been noticed to influence the structure and function of the cornea for decades.The etiology of hypoxia of the cornea is distinct from the rest of the body,mainly due to the separation of cornea from the atmosphere,such as prolonged contact lens wearing or closed eyes.Corneal hypoxia can also be found in corneal inflammation and injury when a higher oxygen requirement exceeds the oxygen supply.Systemic hypoxic state during lung diseases or high altitude also leads to corneal hypoxia when a second oxygen consumption route from aqueous humor gets blocked.Hypoxia affects the cornea in multiple aspects,including disturbance of the epithelium barrier function,corneal edema due to endothelial dysfunction and metabolism changes in the stroma,and thinning of corneal stroma.Cornea has also evolved mechanisms to adapt to the hypoxic state initiated by the activation of hypoxia inducible factor(HIF).The aim of this review is to introduce the pathology of cornea under hypoxia and the mechanism of hypoxia adaptation,to discuss the current animal models used in this field,and future research directions.展开更多
基金supported by The Norwegian Research CouncilDepartment of Ophthalmology,Oslo University Hospital,Oslo,Norway(to TPU)+10 种基金Department of Medical Biochemistry,Oslo University Hospital,Oslo,Norway(to TPU)The Norwegian Association for the Blind and Partially Sighted(to TPU)The Ministry of Science and Technology of Taiwan,China MOST 105-2917-I-002-031,MOST 109-2917-I-564-032(to KC)The Scientific and Technological Research Council of Turkiye-TUBITAK(to KG)BrightFocus Foundation(to KSC)the Massachusetts Lions Foundation(to KSC)National Eye Institute Grant EY031696(to DFC)Harvard NeuroDiscovery Center Grant(to DFC)Department of Defense(USA)HT9425-23-1-1045(to DFC and AL)Core Grant for Vision Research from NIH/NEI to the Schepens Eye Research Institute(P30EY003790)South-Eastern Norway Regional Health Authority and the Norwegian Society of the Blind(to TPU).
文摘Retinitis pigmentosa is a hereditary retinal disease that affects rod and cone photoreceptors,leading to progressive photoreceptor loss.Previous research supports the beneficial effect of electrical stimulation on photoreceptor survival.This study aims to identify the most effective electrical stimulation parameters and functional advantages of transcorneal electrical stimulation(tcES)in mice affected by inherited retinal degeneration.Additionally,the study seeked to analyze the electric field that reaches the retina in both eyes in mice and post-mortem humans.In this study,we recorded waveforms and voltages directed to the retina during transcorneal electrical stimulation in C57BL/6J mice using an intraocular needle probe with rectangular,sine,and ramp waveforms.To investigate the functional effects of electrical stimulation on photoreceptors,we used human retinal explant cultures and rhodopsin knockout(Rho^(-/-))mice,demonstrating progressive photoreceptor degeneration with age.Human retinal explants isolated from the donors’eyes were then subjected to electrical stimulation and cultured for 48 hours to simulate the neurodegenerative environment in vitro.Photoreceptor density was evaluated by rhodopsin immunolabeling.In vivo Rho^(-/-)mice were subjected to two 5-day series of daily transcorneal electrical stimulation using rectangular and ramp waveforms.Retinal function and visual perception of mice were evaluated by electroretinography and optomotor response(OMR),respectively.Immunolabeling was used to assess the morphological and biochemical changes of the photoreceptor and bipolar cells in mouse retinas.Oscilloscope recordings indicated effective delivery of rectangular,sine,and ramp waveforms to the retina by transcorneal electrical stimulation,of which the ramp waveform required the lowest voltage.Evaluation of the total conductive resistance of the post-mortem human compared to the mouse eyes indicated higher cornea-to-retina resistance in human eyes.The temperature recordings during and after electrical stimulation indicated no significant temperature change in vivo and only a subtle temperature increase in vitro(~0.5-1.5°C).Electrical stimulation increased photoreceptor survival in human retinal explant cultures,particularly at the ramp waveform.Transcorneal electrical stimulation(rectangular+ramp)waveforms significantly improved the survival and function of S and M-cones and enhanced visual acuity based on the optomotor response results.Histology and immunolabeling demonstrated increased photoreceptor survival,improved outer nuclear layer thickness,and increased bipolar cell sprouting in Rho^(-/-)mice.These results indicate that transcorneal electrical stimulation effectively delivers the electrical field to the retina,improves photoreceptor survival in both human and mouse retinas,and increases visual function in Rho^(-/-)mice.Combined rectangular and ramp waveform stimulation can promote photoreceptor survival in a minimally invasive fashion.
文摘Streptozotocin(STZ)-induced type I diabetes mellitus(DM)models have been pivotal in diabetes research due to their ability to mimic the insulin-dependent hyperglyce-mia akin to human type I diabetes.However,these models often suffer from poor induction rates and low survival post-STZ induction,especially in long-term experi-ments,necessitating insulin supplementation,which introduces additional variables to experiments.To address this,we present a novel modification to the STZ-induced DM model in C57BL/6J mice to improve survival rates without insulin supplemen-tation.Our method involves non-fasting,low-dose STZ injections dissolved in pH-neutral phosphate buffer saline instead of acidic sodium citrate buffer,administered over 5 days.We observed hyperglycemia induction in 94.28%of mice within a week post-injection,with stable high blood glucose levels,stable body weight,and minimal mortality up to 21 weeks.Notably,omitting 10%sucrose in water and fasting did not affect hyperglycemia induction.Our findings suggest that the modified protocol not only decreases the experimental effort of the researchers,but reduces animal stress and mortality,thus enhancing experimental outcomes and animal welfare.By opti-mizing the STZ-induced DM model in C57BL/6J mice,our study provides a valuable resource for researchers aiming to study diabetes and its complications while mini-mizing experimental variability and animal usage.
文摘The cornea is an avascular,transparent tissue that is essential for visual function.Any disturbance to the corneal transparency will result in a severe vision loss.Due to the avascular nature,the cornea acquires most of the oxygen supply directly or indirectly from the atmosphere.Corneal tissue hypoxia has been noticed to influence the structure and function of the cornea for decades.The etiology of hypoxia of the cornea is distinct from the rest of the body,mainly due to the separation of cornea from the atmosphere,such as prolonged contact lens wearing or closed eyes.Corneal hypoxia can also be found in corneal inflammation and injury when a higher oxygen requirement exceeds the oxygen supply.Systemic hypoxic state during lung diseases or high altitude also leads to corneal hypoxia when a second oxygen consumption route from aqueous humor gets blocked.Hypoxia affects the cornea in multiple aspects,including disturbance of the epithelium barrier function,corneal edema due to endothelial dysfunction and metabolism changes in the stroma,and thinning of corneal stroma.Cornea has also evolved mechanisms to adapt to the hypoxic state initiated by the activation of hypoxia inducible factor(HIF).The aim of this review is to introduce the pathology of cornea under hypoxia and the mechanism of hypoxia adaptation,to discuss the current animal models used in this field,and future research directions.
