overpressure air delivery for the induction of indirect traumatic optic neuropathy (iton) in mice

<meta charset="utf8"></head><body>쥐 모델에서 CNS 부상을 유발하기 위한 맞춤형 과압 공기 시스템

Closed-system central nervous system (CNS) injuries are injuries that are caused by damage to the brain or spinal cord without causing a break in the skull or spinal column. These injuries include traumatic brain injury (TBI) and spinal cord injury (SCI) and can occur from a variety of incidents, including blunt force injuries (e.g., falls, sports injuries, motor vehicle accidents) and explosive blasts. Closed-system CNS injuries are generally considered less severe compared to penetrating CNS injuries, yet they occur more often. However, similar to penetrating injuries, closed-system CNS injuries can result in long-term and progressive health issues, especially after repeated occurrences1,2,3,4,5,6. Concerningly, emerging evidence suggests that even subclinical closed-system CNS injuries, which fall below the diagnostic criteria for a TBI or SCI after a single occurrence7,8,9,10,11,12,13, may evolve into chronic neurodegenerative diseases after repeated injury6,14,15,16. This underscores the urgent need for a better understanding of the mechanisms and consequences of single and repeated closed-system CNS injuries.&#160; Such knowledge is imperative for improved protective and therapeutic approaches. Crucial to this endeavor are animal models that replicate closed-system CNS injuries.
Current animal models of closed-system CNS injuries have been instrumental in advancing our understanding of the pathophysiology and potential protective and therapeutic interventions for these traumas. Rodents are particularly popular due to their low cost, availability, genetic manipulability, ease of handling, well-established behavioral and physiological assays, and more favorable ethical considerations17. Common methods for inducing closed-system TBI in rodents include weight-drop devices18,19, controlled cortical impact (CCI) devices20, and compression-air-driven shock tubes21. For SCI, blunt trauma models typically require laminectomy22,23 or other surgical techniques24 to access the spinal cord or epidural space directly. However, closed-body SCI blast injury models have been developed using compression-air-driven shock tubes 25. Despite providing valuable insights, each of these models has unique limitations. Weight-drop models can have high variability and limited control of injury location and severity, producing experimental and ethical concerns for causing severe, uncontrolled injury26. CCI devices offer precision but require training to operate, may involve a craniotomy, and can suffer from mechanical variability impacting reproducibility27. Shock tubes are generally less invasive but can be difficult to acquire, complex to set up and operate, and can create unrealistic and highly variable injury conditions due to environmental factors, wave reflections, and complex pressure interactions28.
To better study the mechanisms and effects of single and repeat closed-system CNS injuries and their treatments, this paper presents a modular, user-friendly, cost-effective, and non-invasive method. The primary objective of this approach is to enable precise control and flexible modification of injury parameters, including location, severity, and timing. To support this objective, this manuscript provides a detailed protocol for constructing, calibrating, and troubleshooting an overpressure air system, which addresses some of the limitations of existing closed-system CNS injury devices. This system not only offers cost-effectiveness and minimal setup time, but it highly versatile, providing consistent and reproducible results while minimizing ethical concerns and maximizing clinical relevance. Additionally, the system&#8217;s ability to produce a range of closed-system CNS injuries in murine models is described, along with its potential applications in future studies. Notably, the goal of this manuscript is to provide a framework that enables investigators to easily acquire, adapt, and expand this system for their specific needs, thereby furthering ongoing research in CNS trauma. Representative results demonstrating the system&#8217;s efficacy in inducing axonal trauma are also presented.

<meta charset="utf8"></head><body>저자 스포트라이트: 외상성 시신경병증의 이차성 변성을 연구하기 위한 정확하고 임상적으로 관련성 있는 모델 개발

국소, 폐쇄 시스템 중추 신경계 손상 시스템

Our laboratory explores the mechanisms controlling secondary degeneration after ITON, indirect traumatic optic neuropathy, with the goal of developing rational therapies for patients. Currently, the devices to induce CNS injury in the field include controlled cortical impact devices, weight drop models, and compression air-driven shock tubes. We have found that the duration of the interblast exposure interval contributes significantly to the amount of axon degeneration, and that injury to the optic nerve, similar to injury to the brain, significantly elevates the amount of reactive oxygen species.And that contributes to the secondary axon degeneration. This protocol addresses the need for a device that offers precise control over injury location and severity, while maintaining clinical relevance for closed-system injuries. It also offers a way to study the short interblast injury intervals of certain occupational environments.It's also cost effective, easy to set up and use. So while other devices also offer customization, this closed-system injury device stands out for its ease of set up and use. And this protocol provides a detailed framework simplifying this process, enabling other researchers to quickly adapt and set up the device for their own specific experimental goals and needs.

마우스의 간접 외상성 시신경병증(ITON) 유도를 위한 과압 공기 공급

overpressure-air-delivery-for-induction-indirect-traumatic-optic

Research

JoVE Journal

Neuroscience

Overpressure Air Delivery for the Induction of Indirect Traumatic Optic Neuropathy (ITON) in Mice

187 조회수. 시작하려면 발가락 꼬집음에 대한 반응이 없는지 평가하여 쥐의 마취를 확인합니다. 등쪽과 아래쪽 뒷다리는 차폐된 상태로 유지하면서 머리와 위쪽 뒷어깨가 직사각형 구멍을 통해 노출된 상태에서 쥐를 내부 동물 홀더에 고정합니다. 위쪽 뒷어깨에 수술용 테이프를 붙여서 마우스를 고정합니다.내부 동물 홀더를 외부 홀더에 삽입합니다. 동...

비디오: 마우스의 간접 외상성 시신경병증(ITON) 유도를 위한 과압 공기 공급

System for Focal, Closed-System Central Nervous System Injury

The prevalence of closed-system central nervous system (CNS) injuries underscores the need for an enhanced understanding of these traumas to improve protective and therapeutic interventions. Crucial to this research are animal models that replicate closed-system CNS injuries. In this context, a custom overpressure air system was engineered to reproduce a range of closed-system CNS injuries in murine models, including ocular, brain, and spinal cord trauma. To date, the system has been used to administer eye-, head-, or spine-directed overpressure air to model anteroposterior pole injury in the eye, indirect traumatic optic neuropathy (ITON), focal traumatic brain injury, and spinal cord injury. This paper provides a detailed protocol outlining the system&#39;s design and operation and shares representative results demonstrating its effectiveness. The robust framework presented here provides a strong foundation for ongoing research in CNS trauma. By leveraging the system&#8217;s flexible attributes, investigators can modify and carefully control the location, severity, and timing of injuries. This allows for comprehensive comparisons of molecular mechanisms and therapeutic efficacy across multiple closed-system CNS injuries.

This protocol describes a custom overpressure air system designed to induce closed-system central nervous system (CNS) injuries in mice, including ocular, brain, and spinal cord traumas. The goal of this protocol is to provide a framework for researchers to easily adapt and expand the system for their unique CNS trauma studies.

The prevalence of closed-system central nervous system (CNS) injuries underscores the need for an enhanced understanding of these traumas to improve ...

연구

신경과학

To begin, confirm the anesthetization of the mouse by assessing the absence of a response to a toe pinch. Secure the mouse into the inner animal holder with its head and upper hind shoulders exposed through the rectangular opening while the dorsum and lower hind limbs remain shielded. Apply surgical tape across the upper hind shoulders to secure the mouse.Insert the inner animal holder into the outer holder. After opening the secondary anesthesia line inside the animal holder, seal off the end of the holder to prevent the anesthetic from leaking out of the tube and the mouse from moving during the experiment. Align the outer animal holder's four millimeter circular aperture directly over the mouse's left eye.Position the animal holder on the XY table using the control knobs, so that its aperture aligns with the barrel of the paintball gun, and the external surface is five millimeters from the end of the barrel. After calibration, initiate the over-pressure air sequence to deliver two bursts of 15 PSI at an interval of 0.5 seconds. For the sham group mouse, turn the animal holder away from the barrel, block the air with a cardboard shield and expose it to the noise of the over-pressure air.Healthy densely packed axons were observed in the sham group. In contrast, the ITON group exhibited signs of axon degeneration, including irregularities in axon shape and myelin sheath breakdown. The total number of axons significantly decreased in the ITON group compared to the sham group.A significant increase in degenerative profiles was detected in the ITON group compared to the sham group. Increased microglia proliferation was observed in the retina of ITON mice, with microglia extending into the outer nuclear layer. Compared to the sham group, where microglia remained in their typical retinal layers.Intact synaptic connections between rod bipolar cells and photoreceptors were noted in both ITON and sham mice, with no detected synaptopathy.