Name: Autor im Rampenlicht: Fortschritte in der In-vivo- und Ex-vivo-Netzhautbildgebung für eine verbesserte Glaukomdiagnose und -behandlung
Uploaded: 2023-06-30T13:00:00
Description: Watch this Scientific Journal Video about Advancements in In Vivo and Ex Vivo Retinal Imaging for Improved Glaucoma Diagnosis and Treatment at JoVE.com

Diese Studie wird unterstützt durch den Shaffer Grant der Glaucoma Research Foundation, den 4-CA Cavalier Collaborative Award, R01EY029121, R01EY035088 und die Knights Templar Eye Foundation.

Alle Tierbehandlungen wurden vom Institutional Animal Care and Use Committee der University of Virginia genehmigt und entsprachen der Richtlinie zur Verwendung von Tieren des National Institute of Health (NIH). In der Materialtabelle finden Sie Einzelheiten zu allen Materialien, Reagenzien und Instrumenten, die in diesem Protokoll verwendet werden.
1. In-vivo-Vis-OCT-Bildgebung
<ol><li>Das vis-OCT-System<ol><li>Bilden Sie die Augen der Mäuse mit e...

Maus-Retina-OCT-Fibergramm-Ausrichtung mit konfokalen Bildern

<ol>
	<li>Sernagor, E., Eglen, S. J., Wong, R. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+retinal+ganglion+cell+structure+and+function.">Development of retinal ganglion cell structure and function.</a> Progress in Retinal and Eye Research. 20 (2), 139-174 (2001).</li><li>Sanes, J. R., Masland, R. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+types+of+retinal+ganglion+cells:+current+status+and+implications+for+neuronal+classification.">The types of retinal ganglion cells: current status and implications for neuronal classification.</a> Annual Review of Neuroscience. 38, 221-246 (2015).</li><li>Seabrook, T. A., Burbridge, T. J., Crair, M. C., Huberman, A. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Architecture,+function,+and+assembly+of+the+mouse+visual+system.">Architecture, function, and assembly of the mouse visual system.</a> Annual Review of Neuroscience. 40, 499-538 (2017).</li><li>Cang, J., Savier, E., Barchini, J., Liu, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visual+function,+organization,+and+development+of+the+mouse+superior+colliculus.">Visual function, organization, and development of the mouse superior colliculus.</a> Annual Review of Vision Science. 4, 239-262 (2018).</li><li>Quigley, H. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Understanding+glaucomatous+optic+neuropathy:+the+synergy+between+clinical+observation+and+investigation.">Understanding glaucomatous optic neuropathy: the synergy between clinical observation and investigation.</a> Annual Review of Vision Science. 2, 235-254 (2016).</li><li>Whitmore, A. V., Libby, R. T., John, S. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glaucoma:+thinking+in+new+ways-a+role+for+autonomous+axonal+self-destruction+and+other+compartmentalised+processes.">Glaucoma: thinking in new ways-a role for autonomous axonal self-destruction and other compartmentalised processes.</a> Progress in Retinal and Eye Research. 24 (6), 639-662 (2005).</li><li>Syc-Mazurek, S. B., Libby, R. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Axon+injury+signaling+and+compartmentalized+injury+response+in+glaucoma.">Axon injury signaling and compartmentalized injury response in glaucoma.</a> Progress in Retinal and Eye Research. 73, 100769 (2019).</li><li>Puyang, Z., Chen, H., Liu, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Subtype-dependent+morphological+and+functional+degeneration+of+retinal+ganglion+cells+in+mouse+models+of+experimental+glaucoma.">Subtype-dependent morphological and functional degeneration of retinal ganglion cells in mouse models of experimental glaucoma.</a> Journal of Nature and Science. 1 (5), (2015).</li><li>Tatham, A. J., Medeiros, F. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Detecting+structural+progression+in+glaucoma+with+optical+coherence+tomography.">Detecting structural progression in glaucoma with optical coherence tomography.</a> Ophthalmology. 124, S57-S65 (2017).</li><li>Shu, X., Beckmann, L., Zhang, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visible-light+optical+coherence+tomography:+a+review.">Visible-light optical coherence tomography: a review.</a> Journal of Biomedical Optics. 22 (12), 1-14 (2017).</li><li>Miller, D. 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=Visible-light+optical+coherence+tomography+fibergraphy+for+quantitative+imaging+of+retinal+ganglion+cell+axon+bundles.">Visible-light optical coherence tomography fibergraphy for quantitative imaging of retinal ganglion cell axon bundles.</a> Translational Vision Science and Technology. 9 (11), (2020).</li><li>Beckmann, 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=In+vivo+imaging+of+the+inner+retinal+layer+structure+in+mice+after+eye-opening+using+visible-light+optical+coherence+tomography.">In vivo imaging of the inner retinal layer structure in mice after eye-opening using visible-light optical coherence tomography.</a> Experimental Eye Research. 211, 108756 (2021).</li><li>Grannonico, M., 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=Global+and+regional+damages+in+retinal+ganglion+cell+axon+bundles+monitored+non-invasively+by+visible-light+optical+coherence+tomography+fibergraphy.">Global and regional damages in retinal ganglion cell axon bundles monitored non-invasively by visible-light optical coherence tomography fibergraphy.</a> Journal of Neuroscience. 41 (49), 10179-10193 (2021).</li><li>Allen-Worthington, K. H., Brice, A. K., Marx, J. O., Hankenson, F. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intraperitoneal+Injection+of+Ethanol+for+the+Euthanasia+of+Laboratory+Mice+(Mus+musculus)+and+Rats+(Rattus+norvegicus).">Intraperitoneal Injection of Ethanol for the Euthanasia of Laboratory Mice (Mus musculus) and Rats (Rattus norvegicus).</a> J Am Assoc Lab Anim Sci. 54 (6), 769-778 (2015).</li><li>Boivin, G. P., Bottomley, M. A., Schiml, P. A., Goss, L., Grobe, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Physiologic,+Behavioral,+and+Histologic+Responses+to+Various+Euthanasia+Methods+in+C57BL/6NTac+Male+Mice.">Physiologic, Behavioral, and Histologic Responses to Various Euthanasia Methods in C57BL/6NTac Male Mice.</a> J Am Assoc Lab Anim Sci. 56 (1), 69-78 (2017).</li><li>Chen, H., 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=Progressive+degeneration+of+retinal+and+superior+collicular+functions+in+mice+with+sustained+ocular+hypertension.">Progressive degeneration of retinal and superior collicular functions in mice with sustained ocular hypertension.</a> Investigative Ophthalmology and Visual Science. 56 (3), 1971-1984 (2015).</li><li>Feng, L., Chen, H., Suyeoka, G., Liu, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+laser-induced+mouse+model+of+chronic+ocular+hypertension+to+characterize+visual+defects.">A laser-induced mouse model of chronic ocular hypertension to characterize visual defects.</a> Journal of Visualized Experiments: JoVE. 78 (78), (2013).</li><li>Gao, J., 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=Differential+effects+of+experimental+glaucoma+on+intrinsically+photosensitive+retinal+ganglion+cells+in+mice.">Differential effects of experimental glaucoma on intrinsically photosensitive retinal ganglion cells in mice.</a> Journal of Comparative Neurology. 530 (9), 1494-1506 (2022).</li><li>Thomson, B. R., 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=Angiopoietin-1+knockout+mice+as+a+genetic+model+of+open-angle+glaucoma.">Angiopoietin-1 knockout mice as a genetic model of open-angle glaucoma.</a> Translational Vision Science and Technology. 9 (4), (2020).</li><li>Feng, 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=Sustained+ocular+hypertension+induces+dendritic+degeneration+of+mouse+retinal+ganglion+cells+that+depends+on+cell+type+and+location.">Sustained ocular hypertension induces dendritic degeneration of mouse retinal ganglion cells that depends on cell type and location.</a> Investigative Ophthalmology and Visual Science. 54 (2), 1106-1117 (2013).</li><li>Grannonico, M., 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=Longitudinal+analysis+of+retinal+ganglion+cell+damage+at+individual+axon+bundle+level+in+mice+using+visible-light+optical+coherence+tomography+fibergraphy.">Longitudinal analysis of retinal ganglion cell damage at individual axon bundle level in mice using visible-light optical coherence tomography fibergraphy.</a> Translational Vision Science and Technology. 12 (5), (2023).</li></ol>

Es gibt zwei Schritte in diesem Protokoll, die Aufmerksamkeit erfordern. Zunächst muss sichergestellt werden, dass sich das Tier unter Tiefennarkose befindet und dass seine Augen vor der Vis-OCT-Bildgebung vollständig geweitet sind. Wenn die Mäuse nicht ausreichend betäubt werden, kann ihre schnelle Atmung zu instabilen Bewegungen der Gesichtsbilder führen, was sich negativ auf die Qualität des Fibergramms auswirken kann. Darüber hinaus kann sich eine unzureichende Dilatation auch negativ auf die Bildqual...

Retinale Ganglienzellen (RGCs) spielen eine entscheidende Rolle bei der visuellen Informationsverarbeitung, indem sie synaptische Inputs über ihre dendritischen Bäume in der inneren plexiformen Schicht (IPL) empfangen und die Informationen über ihre Axone in der retinalen Nervenfaserschicht (RNFL) an das Gehirn weiterleiten 1,2,3,4. Bei Erkrankungen wie dem Glaukom kann eine frühe RGC-Degeneration sowohl bei Patienten als auch bei Nagetiermodellen zu subtilen Veränderungen der RNFL, der Ganglienzellschicht (GCL), des IPL und des Sehnervs führen 5,6,7,8,9. Die frühzeitige Erkennung dieser morphologischen Veränderungen bei RGCs ist daher für eine rechtzeitige Intervention zur Vorbeugung von RGC und Sehverlust unerlässlich.
Wir haben kürzlich eine neue klinische Bildgebungstechnologie namens optische Kohärenztomographie (Vis-OCT) entwickelt, um den Bedarf an In-vivo-Überwachung von RGC-Schäden zu decken. Vis-OCT verbesserte die axiale Auflösung auf 1,3 μm in der Netzhaut10,11 und ermöglichte die Visualisierung einzelner RGC-Axonbündel in der RNFL. In der Folge wurde die Vis-OCT-Fasergraphie (Vis-OCTF) etabliert, um RGC-Schäden auf der Ebene einzelner Axonbündel bei Mäusen zu verfolgen und zu quantifizieren11,12,13. Eine konfokale Ex-vivo-Bildgebung derselben Netzhaut wie der Goldstandard ist jedoch häufig erforderlich, um die In-vivo-Ergebnisse zu validieren. Daher wird diese Studie zeigen, wie in vivo Bilder, die mit vis-OCTF aufgenommen wurden, mit ex vivo konfokalen Bildern derselben Maus-Netzhaut abgeglichen werden können. Das Protokoll zielt darauf ab, die in vivo Befunde durch konfokale Ex-vivo-Bildgebung zu validieren und eine Grundlage für die Untersuchung der molekularen und zellulären Veränderungen zu schaffen, die RGC-Schäden unter kranken Bedingungen zugrunde liegen.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Equipment</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Halo 100</td>
			<td>Opticent Health, Evanston, IL</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Zeiss LSM800 microscope</td>
			<td>Carl Zeiss</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Drugs and antibodies</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>4% paraformaldehyde (PFA)</td>
			<td>Santz Cruz Biotechnology, SC-281692</td>
			<td></td>
			<td>1-2 drops</td>
		</tr>
		<tr>
			<td>Bovine serum albumin powder</td>
			<td>Fisher Scientific, BP9706-100</td>
			<td></td>
			<td>1:10</td>
		</tr>
		<tr>
			<td>Donkey anti Mouse Alexa Fluor 488 dye</td>
			<td>Thermo Fisher Scientific, Cat# A-21202</td>
			<td></td>
			<td>1:1,000</td>
		</tr>
		<tr>
			<td>Donkey anti rat Alexa Fluor 594 dye</td>
			<td>Thermo Fisher Scientific, Cat# A-21209</td>
			<td></td>
			<td>1:1,000</td>
		</tr>
		<tr>
			<td>Euthasol (a mixture of pentobarbital sodium (390 mg/mL) and phenytoin sodium (50 mg/mL))</td>
			<td>Covetrus, NDC 11695-4860-1</td>
			<td></td>
			<td>15.6 mg/mL</td>
		</tr>
		<tr>
			<td>Ketamine</td>
			<td>Covetrus, NADA043304</td>
			<td></td>
			<td>114 mg/kg</td>
		</tr>
		<tr>
			<td>Mouse anti-Tuj1</td>
			<td>A gift from Anthony J. Spano, University of Virginia</td>
			<td></td>
			<td>1:200</td>
		</tr>
		<tr>
			<td>Normal donkey serum(NDS)</td>
			<td>Millipore Sigma, S30-100 mL</td>
			<td></td>
			<td>1:100</td>
		</tr>
		<tr>
			<td>Phosphate-buffered saline (PBS, 10x), pH 7.4 
			(Contains 1370 mM NaCl, 27 mM KCl, 80 mM Na2HPO4, and 20 mM KH2PO4)</td>
			<td>Thermo Fisher Scientific, Cat# J62036.K3</td>
			<td></td>
			<td>1:10</td>
		</tr>
		<tr>
			<td>Rat anti-ICAM-2</td>
			<td>BD Pharmingen, Cat#553325</td>
			<td></td>
			<td>1:500</td>
		</tr>
		<tr>
			<td>Tropicamide drops&#160;</td>
			<td>Covetrus, NDC17478-102-12</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Triton X-100 
			(Reagent Grade)</td>
			<td>VWR, CAS: 9002-93-1</td>
			<td></td>
			<td>1:20</td>
		</tr>
		<tr>
			<td>Vectashield mounting medium</td>
			<td>Vector Laboratories Inc. H2000-10</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Xylazine</td>
			<td>Covetrus, NDC59399-110-20</td>
			<td></td>
			<td>17 mg/kg</td>
		</tr>
	</tbody>
</table>

alignment of visible-light optical coherence tomography fibergrams with confocal images of the same mouse retina

In den letzten Jahren wurde die In-vivo-Netzhautbildgebung, die nicht-invasive, Echtzeit- und Längsschnittinformationen über biologische Systeme und Prozesse liefert, zunehmend eingesetzt, um eine objektive Beurteilung von neuronalen Schäden bei Augenerkrankungen zu erhalten. Die konfokale Ex-vivo-Bildgebung derselben Netzhaut ist oft notwendig, um die in vivo Befunde zu validieren, insbesondere in Tierversuchen . In dieser Studie haben wir eine Methode demonstriert, mit der ein konfokales ex vivo Bild der Maus-Netzhaut mit ihren in vivo Bildern abgeglichen werden kann. Eine neue klinische Bildgebungstechnologie, die optische Kohärenztomographie (vis-OCTF), wurde eingesetzt, um In-vivo-Bilder der Netzhaut der Maus zu erhalten. Anschließend führten wir die konfokale Bildgebung derselben Netzhaut wie den "Goldstandard" durch, um die in vivo vis-OCTF-Bilder zu validieren. Diese Studie ermöglicht nicht nur die weitere Untersuchung der molekularen und zellulären Mechanismen, sondern schafft auch die Grundlage für eine sensitive und objektive Bewertung von neuronalen Schäden in vivo.

Retinal ganglion cells (RGCs) play a critical role in visual information processing, receiving synaptic inputs through their dendritic trees in the inner plexiform layer (IPL) and transmitting the information via their axons in the retinal nerve fiber layer (RNFL) to the brain1,2,3,4. In diseased conditions such as glaucoma, early RGC degeneration may result in subtle changes in the RNFL, the ganglion cell layer (GCL), the IPL, and the optic nerve in both patients and rodent models5,6,7,8,9. Early detection of these morphological changes in RGCs is thus essential for timely intervention to prevent RGC and vision loss.
We have recently developed a new clinical-ready imaging technology called visible-light optical coherence tomography (vis-OCT) to satisfy the need for in vivo monitoring of RGC damage. Vis-OCT improved the axial resolution, reaching 1.3 &#181;m in the retina10, 11, allowing for the visualization of individual RGC axon bundles in the RNFL. Subsequently, vis-OCT fibergraphy (vis-OCTF) was established to track and quantify RGC damage at the single axon bundle level in mice11,12,13. However, ex vivo confocal imaging of the same retina as the gold standard is often necessary to validate the in vivo findings. Therefore, this study will demonstrate how to align in vivo images acquired by vis-OCTF with ex vivo confocal images of the same mouse retina. The protocol aims to validate the in vivo findings by ex vivo confocal imaging and establish a foundation for examining the molecular and cellular changes underlying RGC damage in diseased conditions.

Autor im Rampenlicht: Fortschritte in der In-vivo- und Ex-vivo-Netzhautbildgebung für eine verbesserte Glaukomdiagnose und -behandlung 

Abgleich von optischen Kohärenztomographie-Fasergrammen im sichtbaren Licht mit konfokalen Bildern derselben Maus-Netzhaut

We present a protocol for aligning in vivo VIS-OCT images with ex vivo immunostained retinal nerve fibers to validate our novel imaging technology. VIS-OCT enables visualization of retinal nerve fibers in vivo, and this process confirms the accuracy of our findings. Our protocol combines in vivo and ex vivo imaging to provide a real time visualization of retina structure and confirm findings.The process is applicable to mouse models of eye diseases, provided the anterior eye portion allows for optical imaging. This includes diabetic retinopathy and retinal ischemia models. These studies lay the foundation for establishing an objective evaluation of neuro damage in humans, which can significantly improve glaucoma diagnosis and treatment in the future.

Das zusammengesetzte Vis-OCT-Fasergramm wird mit dem entsprechenden konfokalen Bild einer flach montierten Netzhaut verglichen, die mit Tuj-1 für RGC-Axone immungefärbt wurde (Abbildung 1D, oben). Axonbündel, die mit vis-OCTF abgebildet werden, können mit den Tu-j1-markierten Axonbündeln auf dem konfokalen Bild abgeglichen werden. Blutgefäße weisen in der Regel unterscheidbare Verzweigungsstrukturen im Vergleich zu umgebenden Axonbündeln in Fibergrammbildern auf, die mit den ICAM-2-m...

Watch this Scientific Journal Video about Advancements in In Vivo and Ex Vivo Retinal Imaging for Improved Glaucoma Diagnosis and Treatment at JoVE.com

Das vorliegende Protokoll beschreibt die Schritte zum Abgleich von in vivo Bildern der optischen Kohärenztomographie (Vis-OCTF) mit konfokalen ex vivo Bildern derselben Mausnetzhaut, um die beobachtete Morphologie der retinalen Ganglienzell-Axonbündel in den in vivo Bildern zu verifizieren.

In recent years, in vivo retinal imaging, which provides non-invasive, real-time, and longitudinal information about biological systems and processes, has ...

Wir präsentieren ein Protokoll für den Abgleich von in vivo VIS-OCT-Bildern mit ex vivo immungefärbten retinalen Nervenfasern, um unsere neuartige Bildgebungstechnologie zu validieren. VIS-OCT ermöglicht die Visualisierung von retinalen Nervenfasern in vivo, und dieser Prozess bestätigt die Genauigkeit unserer Ergebnisse. Unser Protokoll kombiniert In-vivo- und Ex-vivo-Bildgebung, um eine Echtzeit-Visualisierung der Netzhautstruktur zu ermöglichen und die Ergebnisse zu bestätigen.Das Verfahren ist auf Mausmodelle für Augenerkrankungen anwendbar, sofern der vordere Augenabschnitt eine optische Bildgebung ermöglicht. Dazu gehören diabetische Retinopathie- und retinale Ischämiemodelle. Diese Studien legen den Grundstein für eine objektive Bewertung von Neuroschäden beim Menschen, die die Diagnose und Behandlung von Glaukomen in Zukunft deutlich verbessern kann.

alignment-visible-light-optical-coherence-tomography-fibergrams-with

Research

JoVE Journal

Neuroscience

Alignment of Visible-Light Optical Coherence Tomography Fibergrams with Confocal Images of the Same Mouse Retina

In recent years, in vivo retinal imaging, which provides non-invasive, real-time, and longitudinal information about biological systems and processes, has been increasingly applied to obtain an objective assessment of neural damage in eye diseases. Ex vivo confocal imaging of the same retina is often necessary to validate the in vivo findings especially in animal research. In this study, we demonstrated a method for aligning an ex vivo confocal image of the mouse retina with its in vivo images. A new clinical-ready imaging technology called visible light optical coherence tomography fibergraphy (vis-OCTF) was applied to acquire in vivo images of the mouse retina. We then performed the confocal imaging of the same retina as the &#34;gold standard&#34; to validate the in vivo vis-OCTF images. This study not only enables further investigation of the molecular and cellular mechanisms but also establishes a foundation for a sensitive and objective evaluation of neural damage in vivo.

The present protocol outlines the steps for aligning in vivo visible-light optical coherence tomography fibergraphy (vis-OCTF) images with ex vivo confocal images of the same mouse retina for the purpose of verifying the observed retinal ganglion cell axon bundle morphology in the in vivo images.

Forschung

Neurowissenschaften

In Vivo Visible Light Optical Coherence Tomography (OCT) Mouse Retinal Imaging

Start by positioning the anesthetized mouse on the animal holder and securing it with two Velcro straps. Turn on the computer and open the software to activate the laser. Adjust the animal holder to center the laser in the mouse's eye.Visualize the posterior part through an on-face preview, the field of view of the superficial vascular plexus, a B scan, and the retina cross-section within the field of view. Acquire a visible light optical coherence tomography, or vis-OCT volume after making minor adjustments to the optical focus. Align the optical nerve head in each of the four corners of the field of view to cover different retinal areas.Use an intensity-based threshold method to detect the retina surface, and generate vis-OCT fiber grams from the volume. Crop the retinal nerve fiber layer, or RNFL, by selecting the first 16 micrometers depth. Next, calculate the mean intensity projection along the axial direction to generate the fiber gram image composed of retinal ganglion cell axon bundles and surrounding vasculature.Align the blood vessels using a graphics editor to montage the four images post-processing. The composite vis-OCT fiber gram is compared with the corresponding confocal image of flat-mounted retina immunostained with TUJ1 for RGC axons. Blood vessels exhibit distinguishable branching structures which can be matched with the ICAM II labeled blood vessels on the confocal image.Side-by-side comparison between ex vivo confocal microscopy and in vivo vis-OCT revealed identical RGC exon bundle networks and surrounding retinal vasculature.

Optische In-vivo-Kohärenztomographie (OCT) mit sichtbarem Licht Retina-Bildgebung der Maus

Ex Vivo Confocal Imaging of Mouse Retina

Enucleate the eyes of a euthanized mouse, marking the temporal side for orientation purposes. Remove the anterior chamber. Then remove the lens and vitreous and place eye cups in paraformaldehyde for 30 minutes.Wash eye cups with PBS for 30 minutes. Replacing the solution three times. Then, wash with 0.5%Triton X-100 for 30 minutes.Incubate eye cups in the blocking buffer for two hours at room temperature. After immunostaining, isolate the retinas from the eye cups using a microscope. Divide the retinas into four leaves and flat mount them with the retinal ganglion cell layer facing up.Ensure the mark on the temporal side remains attached for orientation. Cover the retinas with mounting medium. Place cover slips.And seal the slides using nail polish. Turn on the confocal microscope and under Locate mode, find the area of interest using the eye piece. Switch to Acquisition mode and set up tiles to cover the entire retina, along with Z-Stack slices for all layers of information.Image at least 25 tiles across the whole retina to achieve a total volume. Project the Z-Stack slices to generate two-dimensional on-face confocal microscopy images. The composite vis-OCT fibergram is compared with the corresponding confocal image of flat mounted retina immunostained with TuJ1 for RGC axons.Blood vessels exhibit distinguishable branching structures which can be matched with the ICAM-2 labeled blood vessels on the confocal image. Side-by-side comparison between ex vivo confocal microscopy and in vivo vis-OCT revealed identical RGC axon bundle networks and surrounding retinal vasculature.

Konfokale Ex-vivo-Bildgebung der Netzhaut der Maus

Alignment of In Vivo and Ex Vivo Mouse Retinal Images

Start by creating a composite image using the four obtained images from each mouse. Utilize a graphics editor to align all the blood vessels, employ the optic nerve head and blood vessel patterns as landmarks for aligning the composite fiber gram overlap the composite images and the confocal images of the same retina stained with ICAM2, to achieve in vivo and ex vivo alignment. The composite vis-oct fiber gram is compared with the corresponding confocal image of flat mounted retina.Immuno stain with TUJ1 for RGC axons. Blood vessels exhibit distinguishable branching structures which can be matched with the ICAM2 labeled blood vessels on the confocal image. Side-by-side comparison between ex vivo confocal microscopy and in vivo vis-oct revealed identical RGC Axon bundle networks and surrounding retinal vasculature.