This study was supported by NeuralStem, Inc., and Johns Hopkins Project RESTORE.

NOTE: All animal procedures were approved by the Johns Hopkins Animal Care and Use Committee. Anesthesia machines require yearly inspection and calibration as necessary.
1. Anesthesia and Positioning
<ol>
	<li>Anesthesia.
	<ol>
		<li>Perform all surgical procedures under anesthesia with 2-3% isofluorane. Confirm appropriate level of anesthesia by toe pinch and breathing rate. Check that the rat does not flinch in response to a toe pinch. 
		NOTE: A flinch indicates anesthesia that is too late and may requir...

<ol>
	<li>Dahlmann-Noor, A., Vijay, S., Jayaram, H., Limb, A., Khaw, P. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Current+approaches+and+future+prospects+for+stem+cell+rescue+and+regeneration+of+the+retina+and+optic+nerve.">Current approaches and future prospects for stem cell rescue and regeneration of the retina and optic nerve.</a> Canadian journal of ophthalmology Journal canadien d'ophtalmologie. 45 (4), 333-341 (2010).</li><li>Quigley, H. A., Iglesia, D. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stem+cells+to+replace+the+optic+nerve.">Stem cells to replace the optic nerve.</a> Eye. 18 (11), 1085-1088 (2004).</li><li>Ghaffarieh, A., 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=Optic+nerve+disease+and+axon+pathophysiology.">Optic nerve disease and axon pathophysiology.</a> International review of neurobiology. 105, 1-17 (2012).</li><li>Fukui, Y., Hayasaka, S., Bedi, K. S., Ozaki, H. S., Takeuchi, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+study+of+the+development+of+the+optic+nerve+in+rats+reared+in+the+dark+during+early+postnatal+life.">Quantitative study of the development of the optic nerve in rats reared in the dark during early postnatal life.</a> Journal of anatomy. 174, 37-47 (1991).</li><li>Celestre, P. C., 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=Minimally+invasive+approaches+to+the+cervical+spine.">Minimally invasive approaches to the cervical spine.</a> The Orthopedic clinics of North America. 43 (1), 137-147 (2012).</li><li>Hallas, B. H., Wells, M. R. <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+Technique+for+Multiple+Injections+into+the+Mammalian+Optic+Nerve.">A Novel Technique for Multiple Injections into the Mammalian Optic Nerve.</a> Kopf Carrier. 54, (2001).</li><li>Harvey, A. R., Hellstrom, M., Rodger, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gene+therapy+and+transplantation+in+the+retinofugal+pathway.">Gene therapy and transplantation in the retinofugal pathway.</a> Progress in brain research. 175, 151-161 (2009).</li><li>Adachi-Usami, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optic+neuritis--from+diagnosis+to+optic+nerve+transplantation.">Optic neuritis--from diagnosis to optic nerve transplantation.</a> Nippon Ganka Gakkai zasshi. 104 (12), 841-857 (2000).</li><li>Slater, B. J., Vilson, F. L., Guo, Y., Weinreich, D., Hwang, S., Bernstein, S. L. <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+inflammation+and+demyelination+in+a+rodent+model+of+nonarteritic+anterior+ischemic+optic+neuropathy.">Optic nerve inflammation and demyelination in a rodent model of nonarteritic anterior ischemic optic neuropathy.</a> Investigative ophthalmology &amp; visual science. 54 (13), 7952-7961 (2013).</li><li>Zarbin, M. A., Arlow, T., Ritch, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regenerative+nanomedicine+for+vision+restoration.">Regenerative nanomedicine for vision restoration.</a> Mayo Clinic proceedings. 88 (12), 1480-1490 (2013).</li></ol>

The authors have no meaningful disclosures to report.

Direct injection into the optic nerve of stem cells or other products intended to facilitate regeneration provides a convenient model compared to other means of injections into the CNS. This technique takes less time, requires less total anesthesia, avoids drilling or removing skull or bone tissue, reduces complications rates and allows for more rapid recovery following surgery. 
The most critical steps in this protocol include: 1. Adequate hemostasis in the surgical field to allow clear visua...

The optic nerve provides an ideal location for central nervous system (CNS) regenerative research including ophthalmologic conditions such as optic neuritis, glaucoma and trauma. Injections of a variety of stem cells have either demonstrated efficacy or shown promise in replacing lost myelin, increasing axonal count and/or preventing degenerative diseases.1,2
The human optic nerve contains approximately 1.2 million parallel axons traveling from the retina to the chiasm with a diameter of approximately 3.0-3.5 mm.3 To model human diseases in the laboratory, the rat has been used frequently. The adult rat optic nerve contains approximately 100,000 axons within a diameter of approximately 0.5 mm.4 One of the major limitations in CNS regenerative research is direct boneless access. Complications and surgical risks to the animal are higher when the skull or vertebrae are removed. Similar to the benefits of minimally-invasive approaches in the spine,5 direct optic nerve injections without opening the skull offer reduced complications and a more rapid recovery.
This technique has been used in previous studies.6 In this manuscript and accompanying video, we demonstrate a minimally-invasive procedure to inject stem cells into the rat optic nerve.

<table border="0" cellpadding="0" cellspacing="0" width="851">
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Name of Material/ Equipment</td>
			<td style="width:151px;">Company</td>
			<td style="width:151px;">Catalog Number</td>
			<td style="width:335px;">Comments/Description</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Lewis rat</td>
			<td style="width:151px;">Charles River</td>
			<td align="right" style="width:151px;">4</td>
			<td>Any rat strain will work.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Anesthesia machine</td>
			<td style="width:151px;">Surgivet</td>
			<td style="width:151px;">CDS9000</td>
			<td>CDS 9000 Small Animal Anesthesia Machine - Pole Mount</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Infusion pump</td>
			<td style="width:151px;">Stoelting</td>
			<td align="right" style="width:151px;">53129</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Dissection microscope</td>
			<td style="width:151px;">National Optical</td>
			<td style="width:151px;">409-411-1105</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Fiber-optic light source</td>
			<td style="width:151px;">Fisher Scientific</td>
			<td style="width:151px;">12-562-21</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Dissection and Stereotaxic Instrument</td>
			<td style="width:151px;">Stoelting</td>
			<td align="right" style="width:151px;">51400</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Pipette Puller</td>
			<td style="width:151px;">Kopf</td>
			<td align="right" style="width:151px;">750</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Pipettes</td>
			<td style="width:151px;">World Precision Instruments</td>
			<td style="width:151px;">18150-6</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Disposable scalpel blades</td>
			<td style="width:151px;">Harvard Apparatus</td>
			<td style="width:151px;">810-15-021</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Iridectomy scissors</td>
			<td style="width:151px;">Electron Microscopy Sciences</td>
			<td style="width:151px;">Uniband LA-4XF</td>
			<td></td>
		</tr>
	</tbody>
</table>

minimally-invasive technique for injection into rat optic nerve

The rat optic nerve is a useful model for stem cell regeneration research. Direct injection into the rat optic nerve allows delivery into the central nervous system in a minimally-invasive surgery without bone removal. This technique describes an approach to visualization and direct injection of the optic nerve following minor fascial dissection from the orbital ridge, using a conjunctival traction suture to gently pull the eye down and out. Representative examples of an injected optic nerve show successful injection of dyed beads.

At the conclusion of the experiment, rats were sacrificed and perfused with 4% paraformaldehyde. The optic nerves were carefully dissected and mounted for cryostat sectioning. Figure 2 shows an example of a rat whole optic nerve at low power in which Evans blue dye was injected in order to visualize the site. The arrow identifies the precise location of the injection. This dissection was done within a few min of the injection as indicated by the restricted diffusion of the dye down the nerve. In other in...

Watch this Scientific Journal Video about Minimally-invasive Technique for Injection into Rat Optic Nerve at JoVE.com

Minimally-invasive Technique for Injection into Rat Optic Nerve

Direct injection into the rat optic nerve is useful for regenerative research. We demonstrate a minimally-invasive technique for direct injection into a rat optic nerve that does not involve opening the skull. Using this method, surgical complications are minimized and recovery is more rapid.

The rat optic nerve is a useful model for stem cell regeneration research. Direct injection into the rat optic nerve allows delivery into the central ...

minimally-invasive-technique-for-injection-into-rat-optic-nerve

Research

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Neuroscience

9.4K Views.  Johns Hopkins University. Direct injection into the rat optic nerve is useful for regenerative research. We demonstrate a minimally-invasive technique for direct injection into a rat optic nerve that does not involve opening the skull. Using this method, surgical complications are minimized and recovery is more rapid. 