We thank the many students and fellows who have worked on this model to improve its effectiveness, and to understand its mechanisms. Special thanks are due to Dr&#39;s. Mary Johnson (University of Maryland-Baltimore), Nitza Goldenberg-Cohen (Schneiderman Childrens Hospital, Petah-Tikva, Israel), Charles Zhang (Einstein Medical College, Bronx, NY), and Valerie Touitou (Hopital Salpetrie, Paris, France). This study was funded in part by RO1 EY015304 to SLB.

This protocol was approved by the University of Maryland Institutional Animal Care and Utilization Committee (IACUC; Baltimore, MD, USA)
1. Experimental Set-up
<ol>
	<li>Make a custom designed contact lens from a clear optical grade circular 7 mm in diameter Plexiglas, of 3 mm thickness. Cut the circular lenses with a drill press. Use a standard drill bit to make the inner curve, and finally polish the outer and inner curves using a contact lens polisher of ultrafine grit (1000/3000).</li>
	...

<ol>
	<li>Banik, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nonarteritic+Anterior+Ischemic+Optic+Neuropathy:+An+Update+on+Demographics,+Clinical+Presentation,+Pathophysiology,+Animal+Models,+Prognosis,+and+Treatment.">Nonarteritic Anterior Ischemic Optic Neuropathy: An Update on Demographics, Clinical Presentation, Pathophysiology, Animal Models, Prognosis, and Treatment.</a> J. Clin. Experimental Ophthalmol. 10, 1-5 (2013).</li><li>IONDT study group. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characteristics+of+patients+with+nonarteritic+anterior+ischemic+optic+neuropathy+eligible+for+the+Ischemic+Optic+Neuropathy+Decompression+Trial.">Characteristics of patients with nonarteritic anterior ischemic optic neuropathy eligible for the Ischemic Optic Neuropathy Decompression Trial.</a> Arch Ophthalmol. 114, 1366-1374 (1996).</li><li>Tesser, R. A., Niendorf, E. R., Levin, L. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+morphology+of+an+infarct+in+nonarteritic+anterior+ischemic+optic+neuropathy.">The morphology of an infarct in nonarteritic anterior ischemic optic neuropathy.</a> Ophthalmology. 110, 2031-2035 (2003).</li><li>Bernstein, S. L., Johnson, M. A., Miller, N. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nonarteritic+anterior+ischemic+optic+neuropathy+(NAION)+and+its+experimental+models.">Nonarteritic anterior ischemic optic neuropathy (NAION) and its experimental models.</a> Prog Retin Eye Res. 30, 167-187 (2011).</li><li>Nicholson, J. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=PGJ2+Provides+Prolonged+CNS+Stroke+Protection+by+Reducing+White+Matter+Edema.">PGJ2 Provides Prolonged CNS Stroke Protection by Reducing White Matter Edema.</a> PLoS One. 7 (12), (2012).</li><li>Goldenberg-Cohen, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oligodendrocyte+Dysfunction+Following+Induction+of+Experimental+Anterior+Optic+Nerve+Ischemia.">Oligodendrocyte Dysfunction Following Induction of Experimental Anterior Optic Nerve Ischemia.</a> Invest Ophthalmol Vis Sci. 46, 2716-2725 (2005).</li><li>Bernstein, S. L., Guo, Y., Kelman, S. E., Flower, R. W., Johnson, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+and+cellular+responses+in+a+novel+rodent+model+of+anterior+ischemic+optic+neuropathy.">Functional and cellular responses in a novel rodent model of anterior ischemic optic neuropathy.</a> Invest Ophthalmol Vis Sci. 44, 4153-4162 (2003).</li><li>Berger, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spectral-Domain+Optical+Coherence+Tomography+of+the+Rodent+Eye:+Highlighting+Layers+of+the+Outer+Retina+Using+Signal+Averaging+and+Comparison+with+Histology.">Spectral-Domain Optical Coherence Tomography of the Rodent Eye: Highlighting Layers of the Outer Retina Using Signal Averaging and Comparison with Histology.</a> PLoS One. 9 (5), (2014).</li><li>Huang, T. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Protective+effects+of+systemic+treatment+with+methylprednisolone+in+a+rodent+model+of+non-arteritic+anterior+ischemic+optic+neuropathy+(rNAION).">Protective effects of systemic treatment with methylprednisolone in a rodent model of non-arteritic anterior ischemic optic neuropathy (rNAION).</a> Exp Eye Res. 131, 69-76 (2015).</li><li>Mantopoulos, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+Experimental+Model+of+Optic+Nerve+Head+Injury.">An Experimental Model of Optic Nerve Head Injury.</a> Invest Ophthalmol Vis Sci. 57, 6222 (2014).</li><li>You, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visual+Evoked+Potential+Recording+in+a+Rat+Model+of+Experimental+Optic+Nerve+Demyelination.">Visual Evoked Potential Recording in a Rat Model of Experimental Optic Nerve Demyelination.</a> J. Vis. Exp. (101), e52934 (2015).</li><li>Templeton, J. P., Geisert, E. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+practical+approach+to+optic+nerve+crush+in+the+mouse.">A practical approach to optic nerve crush in the mouse.</a> Mol Vis. 18, 2147-2152 (2012).</li><li>Magharious, M. M., D'Onofrio, P. M., Koeberle, P. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optic+Nerve+Transection:+A+Model+of+Adult+Neuron+Apoptosis+in+the+Central+Nervous+System.">Optic Nerve Transection: A Model of Adult Neuron Apoptosis in the Central Nervous System.</a> J Vis Exp. (51), e2241 (2011).</li><li>Wang, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Novel+Rodent+Model+of+Posterior+Ischemic+Optic+Neuropathy.">A Novel Rodent Model of Posterior Ischemic Optic Neuropathy.</a> JAMA Ophthalmol. 131 (2), 194-204 (2013).</li><li>Huang, T. L., Chang, C. H., Chang, S. W., Lin, K. H., Tsai, R. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficacy+of+Intravitreal+Injections+of+Antivascular+Endothelial+Growth+Factor+Agents+in+a+Rat+Model+of+Anterior+Ischemic+Optic+Neuropathy.">Efficacy of Intravitreal Injections of Antivascular Endothelial Growth Factor Agents in a Rat Model of Anterior Ischemic Optic Neuropathy.</a> IOVS. 56, 2290-2296 (2015).</li></ol>

Authors have nothing to disclose.

While there are a number of models of optic nerve damage (optic nerve crush12, optic nerve transection13, and PION14), the rNAION model is humane, adaptable to both rats and mice. It more closely resembles the human clinical condition of NAION. This condition includes progressive anterior optic nerve edema, an anterior optic nerve compartment syndrome, focal axonal ischemia, isolated retinal ganglion cell axonal damage and loss over a prolonged time course. The current report gives the ap...

Nonarteritic anterior ischemic optic neuropathy (NAION) is a focal ischemic lesion of the anterior portion of the optic nerve (ON)1. NAION is the most common cause of sudden optic nerve related vision loss in individuals over the age of 502. The mechanism is believed to be a compartment syndrome that results in intraneural edema, and causes compression of the capillaries supplying the axons within the optic nerve3.
Since the ON is actually a central nervous system (CNS) tract, the rodent NAION (rNAION) model can be used to study the mechanisms and responses to isolated CNS white matter strokes. The rNAION model may therefore be useful in dissecting many problems associated with stroke related damage to white matter. It can be used to evaluate different neuroprotective strategies and agents in white matter stroke.
One of the most attractive features of the model is that it is a painless, noninvasive procedure. The laser power can be adjusted to produce various degree of ischemic damage. Another feature is that it relies on laser induced superoxide radicals to damage the capillary endothelium, producing a progressive capillary dysfunction. It is this dysfunction and progressive edema that is believed to be remarkably similar to the mechanism that causes NAION. Research has shown that it does not cause direct capillary clotting, but works through at least two mechanisms: superoxide induced death and stripping of some of the capillary endothelial cells4, and NFkB (nuclear factor kappa-light-chain-enhancer of activated B cells) associated inflammatory up regulation in remaining endothelium, with increased fluid transport across the cell membranes into the interstitium5 . The closure of the optic nerve capillaries and compression caused by interstitial fluid accumulation result in optic nerve head ischemia. A schematic picture is shown in Figure 2. The rNAION model can be used in both rat and mouse species6,7, and can be varied in the level of its severity, from a mild lesion to a complete, but painless destruction of the optic nerve and the retina, such as central retinal artery occlusion(CRAO).

<table border="0" cellpadding="0" cellspacing="0" width="600">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">50mW 532nm laser</td>
			<td style="width:99px;">Iridex</td>
			<td style="width:119px;"></td>
			<td style="width:167px;">Standard Ophthalmic Laser</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">0-100mW 532nm laser</td>
			<td style="width:99px;">Laserglow technologies</td>
			<td style="width:119px;"></td>
			<td>Substitute for iridex</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Laser slit lamp adapter</td>
			<td style="width:99px;">Iridex</td>
			<td style="width:119px;"></td>
			<td>SMA coupled adapter for laser output</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Cpherent Fieldmate laser meter with thermopile sensor</td>
			<td style="width:99px;">Coherent</td>
			<td style="width:119px;"></td>
			<td>others also appropriate</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Ophthalmic Examing Slit lamp biomicroscope</td>
			<td style="width:99px;">VArious</td>
			<td style="width:119px;"></td>
			<td>Haag-Streit is the best; cheaper versions available on ebay</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Rose Bengal</td>
			<td style="width:99px;">Sigma</td>
			<td style="width:119px;">330000-1G</td>
			<td>Photoinducing agent</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">Fundus Contact lens or glass cover slip</td>
			<td style="width:99px;">custom/Cantor and Nissel (UK)</td>
			<td style="width:119px;"></td>
			<td>Custom designed planoconvex plastic lens for eye exam and induction</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Tropicamide 1%</td>
			<td style="width:99px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Tamiya polishing compound</td>
			<td style="width:99px;">Tamiya, INC</td>
			<td align="right" style="width:119px;">87068</td>
			<td>polishing contact lens</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">2.5% Hypromellose (Goniovisc)/1% Methycellulose</td>
			<td style="width:99px;">HUB Pharmaceuticals</td>
			<td style="width:119px;"></td>
			<td>contact lens coupling agent</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">2.5% Neosynephrine Ophthalmic drops</td>
			<td style="width:99px;">Alcon labs</td>
			<td style="width:119px;"></td>
			<td>pupil dilating agent</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Tropicamide 1%</td>
			<td style="width:99px;">Alcon labs</td>
			<td style="width:119px;"></td>
			<td>pupil dilating agent</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">0.5% Proparacaine</td>
			<td style="width:99px;">Alcon labs</td>
			<td style="width:119px;"></td>
			<td>topical Anesthetic</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">30ga fused needle insulin syringe</td>
			<td style="width:99px;">Various</td>
			<td style="width:119px;">Various</td>
			<td>for intravenous injection of rose bengal</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">Ophthamic Antibiotic ointment with dexamethasone added (Triple antibiotic ointment)</td>
			<td style="width:99px;">Various</td>
			<td style="width:119px;">Various</td>
			<td>Apply after induciton to minimize corneal scarring</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">Heidelberg Corporation Spectral domain-Optical Coherence Tomograph</td>
			<td style="width:99px;">Heidelberg Corportion</td>
			<td style="width:119px;"></td>
			<td>For Optical coherence measurements baseline and post-induction; not essential for induction</td>
		</tr>
	</tbody>
</table>

the rodent model of nonarteritic anterior ischemic optic neuropathy (rnaion)

Nonarteritic anterior ischemic optic neuropathy (NAION) is a focal ischemic lesion of the optic nerve that affects 1/700 individuals throughout their lifetime. NAION results in optic nerve edema, selective loss of the retinal ganglion cell neurons (RGCs) and atrophy of the optic nerve. A rodent model of NAION that expresses most NAION features and sequelae has been developed, which is applicable to both rats and mice. This model utilizes a focal laser application of 532 nm wavelength to illuminate a photoactive dye, Rose Bengal (RB), to cause capillary damage and leakage at the targeted anterior optic nerve (the laminar region). After rNAION induction, there is an early optic nerve ischemia, optic nerve edema, and intraneural inflammation, followed by selective RGC and axonal loss. Since the optic nerve is a CNS white matter tract, the rNAION model is applicable to mechanistic studies of selective white matter ischemia, as well as neuroprotective analyses and short and long-term mechanisms of glial and neuronal response to ischemia.

The contact lens enabled central retina visualization (Figure 1). The focal laser spot illuminates the optic disc at the back of the retina (Figure 2). The normal un-induced retina is shown imaged by slit lamp bio-microscope (Figure 3A) and by SD-OCT (Figure 3B and 3C). During laser induction, when no dye is present in the circulation, laser light does not result in vessel and disk fluorescence (Figure 4A...

Watch this Scientific Journal Video about The Rodent Model of Nonarteritic Anterior Ischemic Optic Neuropathy rNAION at JoVE.com

The Rodent Model of Nonarteritic Anterior Ischemic Optic Neuropathy rNAION

The following report describes how to replicate the rodent model of nonarteritic anterior ischemic optic neuropathy (rNAION), using the appropriate dye, contact lens and laser parameters. We also reveal the appropriate steps for evaluating the rNAION lesion in vivo.

The Rodent Model of Nonarteritic Anterior Ischemic Optic Neuropathy (rNAION)

Nonarteritic anterior ischemic optic neuropathy (NAION) is a focal ischemic lesion of the optic nerve that affects 1/700 individuals throughout their ...

The overall goal of this procedure, is to produce a rodent model of anterior ischemic optic neuropathy, for use in characterizing stroke response mechanisms. And for analyzing the ethicacy of neuroprotective agents in the treatment of optic nerve stroke. This measure can help answer key questions in the field of optic nerve stroke.Including, mechanisms of edema, post-stroke inflammation, and pass-ways of protection and repair. The main advantage of this technique is that the ischemic damage is isolated to the anterior portion of optic nerve. Without surgery, the technique is painless.And the severity of the damage can be reproducibly varied at will. This method avoids the pain associated with many nerve damage models. Including, crushing, or cutting the optic nerve.It also enables detailed analysis of the effects of isolated exo-ischemia, on a single neuron class, in vivo. Start by obtaining a custom made contact lens designed according to the specifications shown. Also, prepare 2.5 milimaler rose bengal, in pH 7.4 phosphate buffered saline.Fills are sterilized with a 0.5 micron syringe filter. And prepare one millimeter aliquots, place the aliquots in a light, tight, container and store at negative 20 degrees Celsius for up to six months. On the day of the procedure, set up the frequency doubled neodymium yttrium aluminum garnet ophthalmic medical laser.Which generates a 532 nanometer laser light. Mount the laser on a Haag-Streit ophthalmic slit lamp, using a standard ophthalmic laser adapter, to enable simultaneous visualization of the animals eye, and laser spot application. Turn on the laser, and allow it to warm for at least five minutes, before use.Set the appropriate laser power parameters for the experimental animal used. Mount a high ASA speed digital camera on one of the eye pieces of the slit lamp, with a custom made adapter. After appropriately, anesthetizing the experimental animal, and ensuring the appropriate level of anesthesia, by the absence of the response to a toe pinch.Dilate the animals pupils with one percent tropicamide. And anesthetize the surface of the eye, with 0.5 percent proparacaine. Then, use the scissors to cut the whiskers close to the muzzle on the side of the induction, to allow a clear view of the eye.Next, put a drop of one percent methylcellulose, or other ophthalmic coupling drop, onto the inside of the custom made contact lens. And then apply the lens onto the rats eye. Place the animal on a platform, adjusted to the height of the slit lamp.Set the animals head at a 45 degree angle, so that the eye is perpendicular to the slit lamp and laser beam. Then, visualize the eye through the ophthalmic slit lamp. In a healthy eye, the optic nerve head has a clear border and a reddish surrounding Q.And the retinal vessels are thin and evenly distributed.Make sure the aiming beam is the correct size. As well as focused and centered directly on the visualized optic nerve. Then photograph the retinal fundus, using the digital camera.Next, inject one milligram per kilogram, of rose bengal intravenously through the tail vein. And wait for 30 seconds. A smooth, continuous, intervaneous injection of rose bengal, must be followed after 30 seconds, by laser exposure, of the optic nerve head.Variation in time, between these two steps, result in increase variability of degree of optic nerve stroke damage. Which can bias your results. After 30 seconds, activate the laser power.The optic nerve, shows a golden glow within the vessels, emerging from the disc at the laser spot sight. Indicating rose bengal in the blood stream, illuminated by the green laser light. Immediately after induction, remove the contact lens, cover both eyes, with ophthalmic triple antibiotic ointment, dexamethasone.Single house the animal, in a cage on a 37 degree Celsius warming pad, under close observation until full recovery. This colored fundus picture, shows optic nerve swelling and optic disc pallor. With loss of the surrounding choroidal flush.The veins are enlarged, and curve. This n-face SDOCT picture, post-induction, shows disc edema, and venous dilation. The scan direction is indicated with a green arrow, the cross section in the next image, is generated from within the green box.Here, a cross section, shows optic nerve disc edema, as evidenced by reduced gray intensity, and increased thickness of the retinal nerve fiber layer. Consistent with higher water content. The diameter of the intraretinal optic nerve, indicated between the black arrows, is increased.While attempting this procedure, it is important to remember to have a clean, polished, contact lens. Or cover slip, that enables good visualization of the nerve, and precise focusing, of the laser light over the nerve. Following this procedure, other methods like, immunohistochemistry, cytokine analysis, or gene expression analysis, can be performed in order to answer additional questions.Like inflammatory responses after stroke, or changes in the target tissues.

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8.8K visualizações.  University of Maryland-Baltimore School of Medicine. The overall goal of this procedure, is to produce a rodent model of anterior ischemic optic neuropathy, for use in characterizing stroke response mechanisms. And for analyzing the ethicacy of neuroprotective agents in the treatment of optic nerve stroke. This measure can help answer key questions in the field of optic nerve stroke.Including, mechanisms of edema, post-stroke inflammation, and pass-ways of protection and repair. The main advantage of this technique is that the ischemic d...