Rat Models of Optic Nerve Crush and Axotomy in the MICRON Literature

About the MICRON Research Literature

These research pages organize published studies using MICRON imaging systems by animal species and the disease or condition investigated.

All publication counts and figures reflect the complete indexed research collection.

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Understanding Optic Nerve Crush and Axotomy

Optic nerve crush and axotomy are surgical preparations rather than diseases: the optic nerve is reached behind the globe and the retinal ganglion cell axons running through it are interrupted at a site and a moment the experimenter chooses.

The two operations the label spans are not interchangeable. The difference is the nerve sheath:

• A crush compresses the axons while leaving the sheath and the distal glial tube in continuity, so a regrowing axon has a path to follow and a graded injury can spare part of the population
• A transection divides the sheath as well and the severed ends separate, which is why a regeneration result obtained after one operation does not carry across to the other

Optic Nerve Crush and Axotomy in Experimental Research

What the preparation buys is control over the insult, since its position, its force and its duration are set by the operator rather than by a disease process. The preparation gives the axons a common injury time, so degeneration can be measured from a known zero rather than inferred from an unknown disease onset. Individual retinal-ganglion-cell subtypes nevertheless differ substantially in their susceptibility and survival after the injury.

Because that zero is shared, what is measured at a given interval after it can be set beside the same interval in another animal, under another treatment or in another laboratory, with the unoperated fellow eye available as a within-animal comparison wherever the measure in question is not itself altered by injury to the other side.

What it costs is the antecedent: apart from direct trauma to the orbit, human optic neuropathy does not begin with a mechanical injury delivered in one moment. Human optic neuropathy reaches the axon instead through:

• Raised intraocular pressure
• Ischemia
• Inflammation
• Demyelination
• A genetic or mitochondrial lesion acting over months to years

An effect on survival or on regrowth demonstrated after a dated axon injury is accordingly evidence about the response to that injury, and whether it holds where axons are injured slowly and by another mechanism is a separate question this preparation is not built to settle.

Because the lesion itself sits behind the eye and out of view, what the living animal offers is the retina the injured cells occupy and what the animal can still see, followed in one eye before and after an insult whose timing is known.

Rat Models of Optic Nerve Crush and Axotomy

The rat offers a larger eye than the mouse while remaining a small-animal model, which eases injection and imaging without moving to a large species.

Published MICRON Research: Optic Nerve Crush and Axotomy in Rats

This page lists 4 papers from the MICRON literature, published 2019 to 2025, that study optic nerve crush or axotomy in rats.

Of these publications:

• 4 studies used rats as the primary optic nerve crush or axotomy disease model.

Scope of the literature collection: Publication counts reflect studies identified and indexed in the MICRON research corpus. This collection is not intended to represent an exhaustive review of all published optic nerve crush or axotomy research.

Which imaging and experimental techniques are used in these studies?

Technique counts are paper-level co-occurrences and do not necessarily indicate that a technique was applied to the focal species or focal disease model.

Capabilities and Limitations of Imaging Techniques

A summary of what each imaging technique listed above can measure, the information it provides, and its limitations in research applications.

Intravitreal Injection / Delivery

Injection into the vitreous places a substance directly into the vitreous at a known administered dose and chosen time, reducing but not eliminating systemic exposure. The injectate may be a therapeutic compound, cell preparation or viral vector, or an agent used to create the model, such as a toxin, vasoactive or excitotoxic compound, or infectious inoculum. The route bypasses surface-delivery barriers and provides direct access to the vitreous and posterior segment, but the concentration reached in a particular ocular tissue depends on distribution and clearance and is not fixed by the injected dose alone. It is invasive and discrete: each repeat dose or challenge requires another injection, and vehicle- or sham-injected controls can help separate effects of the injectate from effects of the procedure.

Optical Coherence Tomography

Optical coherence tomography provides high-resolution, cross-sectional images of ocular tissues in the living eye, allowing researchers to visualize structures at different depths. OCT is particularly useful for measuring tissue thickness, identifying structural abnormalities, and assessing the location and extent of tissue changes.

As a non-invasive imaging technique, OCT enables repeated measurements in the same eye over time, supporting longitudinal studies of disease progression and treatment response. Although OCT provides detailed structural information, it does not directly measure cellular activity or visual function. Tissue that appears structurally normal may still have functional abnormalities, making OCT a valuable companion to functional assessments such as electroretinography (ERG).

Topical Ophthalmic Drug Delivery

A compound applied as drops to the ocular surface. It is non-invasive and repeatable, so it supports frequent dosing without a procedure for each dose. What the route has to establish depends on the target: for an ocular-surface target, residence time and penetration into the surface tissue are the main barriers; for an intraocular anterior-segment target, the compound must cross ocular-surface and corneal or conjunctival barriers and reach an intraocular concentration sufficient for the experiment; for a posterior-segment target, additional ocular barriers separate the surface from the target and posterior-segment exposure is harder to establish.

Electroretinography

Records the retina's electrical response to light, giving component-sensitive information about outer- and inner-retinal function. It measures function directly, which no structural method does. Full-field ERG sums across the whole retina, so a small lesion can leave the trace unchanged; focal and multifocal variants trade signal amplitude for spatial resolution.

Optokinetic / Optomotor Response

Measures a reflexive head or eye movement tracking a moving pattern, giving a rapid, training-free behavioral estimate of spatial vision and contrast sensitivity in an animal that cannot report them. It is driven largely by reflex circuitry and reports on the visual pathway as a whole, so a deficit it detects still has to be localized by a structural or electrophysiological method, or separated from cortical processing by an operant task.

Which MICRON systems and add-ons appear?

Which strains and genetic lines are used?

Which other species appear alongside?

What other conditions are recorded on the same papers?

Which MICRON configurations appear in this work?

Configurations recorded in these papers, and the techniques recorded alongside them.

The papers

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