Name: mouse eye enucleation for remote high-throughput phenotyping
Uploaded: 2011-11-19T14:00:00.000+00:00
Duration: 5 min 30 s
Description: Watch this Scientific Journal Video about Mouse Eye Enucleation for Remote High-throughput Phenotyping at JoVE.com

Research to Prevent Blindness; Bartly J. Mondino M.D., Director of the Jules Stein Eye Institute, UCLA; and Ramiro Ramirez-Solis, Jacqui White, and Jeanne Estabel at the Sanger Institute, Wellcome Trust Genome Campus. This research complies with the ARVO Statement for the Use of Animals in Ophthalmic and Visual Research.

1. Blunt Dissection: Enucleation of the mouse eye in unfixed specimens
<ol>
 <li>Pull apart the eyelids to improve exposure and access to the posterior globe (eyeball) surface. </li>
 <li>Place a curved dressing forcep behind (under) the globe in the orbit (eye socket). The Mahajan Sharptip dressing forcep is a custom instrument with pointed tips to make this step easier (see materials and reagents table).</li>
 <li>Close the forcep and grasp the orbital connective tissue and optic nerve behind the globe while being careful to avoid squeezing the globe.</li>
 <li>Gently pull the forcep upward and pluck the eyeball from the orbit. The white thread-like tissue is the optic nerve.</li>
 <li>Place the eye in PBS. Using a 30-gauge needle, make a single puncture wound immediately posterior to the limbus by inserting the needle 1-2 mm into the eyeball. This allows fixatives, such as glutaraldehyde, that are otherwise unable to penetrate the eye tissue, to directly enter the eye. Creation of this puncture wound may not be necessary if a fixative, such as paraformaldehyde or alcohol, is capable of diffusing into ocular tissues of interest.</li>
 <li>Place the entire eye immediately into fixative for immersion fixation.</li>
</ol>
2. Sharp Dissection: Enucleation of the mouse eye following perfusion fixation
<ol>
 <li>Use a curved colibri forcep to hold the eyelid away from the globe.</li>
 <li>Orient curved Westcott dissection scissors parallel to the globe, while aiming towards the back of the orbit.</li>
 <li>Cut the fixed connective tissue that surrounds the globe from the inferior, medial, superior, and lateral sides.</li>
 <li>Place the curved forcep behind the globe, grasp the connective tissue without pressing on the globe, and pull forward to enucleate the eye. Since the orbital connective tissue is stiff from perfusion fixation, additional cutting of orbital tissues may be necessary to completely release the globe.</li>
</ol>
3. Fixation and Packaging
Shipping of fixed tissues must follow your institutional and postal service requirements including appropriate labels and packaging. The following protocol is an example of shipping a non-infectious biological sample at ambient temperature. This requires 3 layers of packaging but no class A/B biological substance or liquid nitrogen labels.
<ol>
 <li>Place the eye into a 5-mL glass scintillation vial with at least 3-mL fixative, or post-fixative buffer if fixation is short. Write the tracking number on the lid of the vial and seal it with Parafilm.</li>
 <li>Place scintillation vials into a biological sample approved shipping container. In our institute, for example, approved containers require three layers: a sealed container in which the sample is placed, an absorbent middle layer, and a protective outer layer. </li>
 <li>Place the container into a bubble-wrap package and then into an approved laboratory shipping container along with appropriate documentation.</li>
</ol>
4. Representative Results
Histological examination of eyes can be performed by a variety of methods including Hematoxylin and Eosin staining, enzymatic expression detection, transmission electron microscopy, and immunohistochemistry. Following immersion fixation in 4% paraformaldehyde, tissue was embedded in paraffin and sectioned on a microtome. In high-throughput phenotyping, we analyze pupil-optic nerve sections that sample all tissue types in the eye (Figure 1). Sections of tissue were also examined for lacZ expression (Figure 2), transmission electron microscopy of cellular organelles (Figure 3), and expression of specific molecules with antibodies (Figure 4).
In our phenotype screening method, it was not important to maintain orientation of the eye with respect to the nasal (medial canthus) and temporal (lateral canthus) sides. There are at least two options if eye orientation is necessary. After enucleation, we have applied light cautery to the temporal cornea at the three o’clock position with a handheld cautery device. The lesion is obvious on histology and does not get lost during processing like histological inks. The downside is that cautery damages the cornea, which may be a critical tissue for examination. The other option requires a skilled anatomist that can identify the extraocular muscle insertions. Under a stereomicroscope, identification of the inferior and superior oblique muscle insertion marks the inferior and superior and aspect of the globe.3 With either orientation method, it is important to track the specimen as a right or left eye. Together, this will allow exact globe orientation prior to sectioning.
<img src="/files/ftp_upload/3184/3184fig1.jpg" alt="Eye anatomy histology: cross-section diagrams of retina layers, lens, and vitreous chamber." data-altupdatedat="1747911167000" data-alt="Figure 1"> 
Figure 1. Mouse eye histological images after remote acquisition. Mouse eyes were enucleated by sharp dissection following perfusion fixation with 4% paraformaldehyde. A. Pupil-optic nerve section stained with Hematoxylin and Eosin shows preservation of all tissue substructures. ON, optic nerve. (green scale bar = 500 microns) B. A higher magnification view of the normal retina shows its laminar structure: RGC, retinal ganglion cells; IPL, inner plexiform layer; INL, inner nuclear layer; OPL, outer plexiform layer; ONL, outer nuclear layer (photoreceptor cell)(arrow); IS, photoreceptor inner segments (arrow head); OS, photoreceptor outer segments; RPE, retinal pigment epithelium; C, choroid. (green scale bar = 50 microns) C. Compared to the normal retina, this specimen is thinner due to photoreceptor degeneration. The ONL, IS, and OS are completely absent (arrow). (green scale bar = 50 microns) 
<img src="/files/ftp_upload/3184/3184fig2.jpg" alt="Ciliary epithelium microscopic diagram; retinal tissue layers; histological staining; epithelial study." data-altupdatedat="1747911167000" data-alt="Figure 2"> 
Figure 2. lacZ expression in transgenic mice. Eyes were enucleated by blunt dissection and immersed in 1 mg/ml X-gal solution (5 mM K3Fe(CN)6, 5 mM K4Fe(CN)6, 2 mM MgCl2, 0.02% NP40, and 0.1% sodium deoxycholate) overnight at 37°C. Eyes were fixed in 2% formaldehyde/0.2% glutaraldehyde for 30 minutes and sectioned on a microtome. X-gal product (blue) labels: A. Ciliary epithelium, B. corneal epithelium, and C. the retinal ganglion cell (RGC) layer in the retina. INL, inner nuclear layer; ONL, outer nuclear layer.
<img src="/files/ftp_upload/3184/3184fig3.jpg" alt="Retinal structure electron micrograph; rod cells, RPE, Bruch's membrane for cell biology study." data-altupdatedat="1747911167000" data-alt="Figure 3"> 
Figure 3. Transmission electron microscopy of retinal pigment epithelium (RPE). After blunt dissection and creation of a puncture wound, eyes were immersion fixed in 2.5% Paraformaldehyde/ 2.5% Glutaraldehyde in 0.1M sodium phosphate buffer. Eyes were secondarily fixed in 1% osmium textroxide, gradually dehydrated, and embedded in Spurr’s resin. Tissue was sectioned at 90 nm and placed onto copper slot grids covered in Formvar and imaged using a transmission electron microscope. The micrograph shows, photoreceptor outer segments of the neurosensory retina, melanosomes (M) within the retinal pigment epithelium, and Bruch’s membrane. 
<img src="/files/ftp_upload/3184/3184fig4.jpg" alt="Fluorescence microscope image of green-stained sample; bacterial biofilm structures visible, 20 microns scale." data-altupdatedat="1747911167000" data-alt="Figure 4"> 
Figure 4. Immunohistochemical labeling of superoxide dismutase-3 (green) in the mouse vitreous. Eyes were enucleated by blunt dissection and underwent immersion fixation in 4% paraformaldehyde. They were embedded in paraffin and sectioned using a microtome. Tissue sections were incubated with rabbit polyclonal SOD3 antiserum diluted 1:50. SOD3 expression was detected using a goat anti-rabbit IgG (H+L)-Alexa Fluor 488 conjugated secondary antibody. Labeling of SOD3 is shown in green.

<ol>
	<li>Song, B. J., Tsang, S. H., Lin, C. -. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetic+models+of+retinal+degeneration+and+targets+for+gene+therapy.">Genetic models of retinal degeneration and targets for gene therapy.</a> Gene Ther. Mol. Biol. 11, 229-262 (2007).</li><li>Mahajan, V. B., Mondino, B. J., Tsang, S. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+high-throughput+Mouse+Eye+Phenomics+System.">A high-throughput Mouse Eye Phenomics System.</a> Cold Spring Harbor Laboratories, Mouse Genetics Meeting. , (2010).</li><li>Smith, R. S., John, S. W. M., Nishina, P. M., Sundberg, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> In Research Methods For Mutant Mice. , (2002).</li><li>Chang, B., Hawes, N. L., Hurd, R. E., Davisson, M. T., Nusinowitz, S., Heckenlively, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Retinal+degeneration+mutants+in+the+mouse.">Retinal degeneration mutants in the mouse.</a> Vision Res. 42, 517-525 (2002).</li><li>Anderson, M. G., Smith, R. S., Hawes, N. L., Zabaleta, A., Chang, B., Wiggs, J. L., 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=Mutations+in+genes+encoding+melanosomal+proteins+cause+pigmentary+glaucoma+in+DBA/2J+mice.">Mutations in genes encoding melanosomal proteins cause pigmentary glaucoma in DBA/2J mice.</a> Nat. Genet. 30, 81-85 (2002).</li><li>Hawes, N. L., Smith, R. S., Chang, B., Davisson, M., Heckenlively, J. R., 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=Mouse+fundus+photography+and+angiography:+a+catalogue+of+normal+and+mutant+phenotypes.">Mouse fundus photography and angiography: a catalogue of normal and mutant phenotypes.</a> Mol. Vis. 5, 22-22 (1999).</li><li>Won, J., Shi, L. Y., Hicks, W., Wang, J., Hurd, R., Naggert, J. K., Chang, B., Nishina, P. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mouse+model+resources+for+vision+research.">Mouse model resources for vision research.</a> J. Ophthalmol. 2011, 391384-391384 (2011).</li><li>Pinto, L. H., Vitaterna, M. H., Siepka, S. M., Shimomura, K., Lumayag, S., Baker, M., Fenner, D., Mullins, R. F., Sheffield, V. C., Stone, E. M., Heffron, E., Takahashi, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Results+from+screening+over+9000+mutation-bearing+mice+for+defects+in+the+electroretinogram+and+appearance+of+the+fundus.">Results from screening over 9000 mutation-bearing mice for defects in the electroretinogram and appearance of the fundus.</a> Vision. Res. 44, 3335-3345 (2004).</li><li>Heckenlively, J. R., Winston, J. V., Roderick, T. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Screening+for+mouse+retinal+degenerations.+I.+Correlation+of+indirect+ophthalmoscopy,+electroretinograms,+and+histology.">Screening for mouse retinal degenerations. I. Correlation of indirect ophthalmoscopy, electroretinograms, and histology.</a> Doc. Ophthalmol. 71, 229-239 (1989).</li><li>Tsang, S. H., Gouras, P., Yamashita, C. K., Kjeldbye, H., Fisher, J., Farber, D. B., Goff, S. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Retinal+degeneration+in+mice+lacking+the+gamma+subunit+of+the+rod+cGMP+phosphodiesterase.">Retinal degeneration in mice lacking the gamma subunit of the rod cGMP phosphodiesterase.</a> Science. 272, 1026-1029 (1996).</li><li>Tsang, S. H., Woodruff, M. L., Jun, L., Mahajan, V., Yamashita, C. K., Pedersen, R., Lin, C. S., Goff, S. P., Rosenberg, T., Larsen, M., Farber, D. B., Nusinowitz, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transgenic+mice+carrying+the+H258N+mutation+in+the+gene+encoding+the+beta-subunit+of+phosphodiesterase-6+(PDE6B)+provide+a+model+for+human+congenital+stationary+night+blindness.">Transgenic mice carrying the H258N mutation in the gene encoding the beta-subunit of phosphodiesterase-6 (PDE6B) provide a model for human congenital stationary night blindness.</a> Hum. Mutat. 28, 243-254 (2007).</li></ol>

No conflicts of interest declared.

Most transgenic mice exist in laboratories that do not examine the eyes. Our video technique illustrates a simple, standardized method for remote surgical skill transfer to optimize tissue acquisition from laboratories with little experience with the eyes. This video technique helps overcome a major pitfall in high-throughput phenotyping, which is the use of a limited number of expert sites due to non-standardized tissue collection and fixation methods that prevent meaningful comparative phenotypic and molecular studies....

<table><tbody><tr><td>Curved Dressing Forcep</td><td>Storz Ophthalmics</td><td>E1408</td><td></td></tr><tr><td>Mahajan Sharptip dressing forcep</td><td>Storz Ophthalmics</td><td>E1406 (REF SP7-64520)</td><td></td></tr><tr><td>Curved Westcott Scissors</td><td>Storz Ophthalmics</td><td>E3321 WH</td><td></td></tr><tr><td>15&amp;#x00B0; BD Beaver Microsurgical Blade</td><td>BD Biosciences</td><td>374881</td><td></td></tr><tr><td>0.22 Fine-Castroviejo Suturing Forceps</td><td>Storz Ophthalmics</td><td>E1805</td><td></td></tr><tr><td>0.12 Colibri forceps</td><td>Storz Ophthalmics</td><td>2/132</td><td></td></tr><tr><td>30-gauge needle</td><td>BD Biosciences</td><td>305128</td><td></td></tr><tr><td>Biohazard Mailer</td><td>Fisher Scientific</td><td>03-523-4</td><td></td></tr><tr><td>Parafilm</td><td>Fisher Scientific</td><td>13-374-10</td><td></td></tr><tr><td>Glass scintillation vials</td><td>Wheaton</td><td>4500413033</td><td></td></tr><tr><td>PBS, pH 7.4</td><td>Invitrogen</td><td>70011-044</td><td></td></tr><tr><td>16% Paraformaldehyde</td><td>Electron Microscopy Sciences</td><td>15700</td><td></td></tr><tr><td>2.5% Paraformaldehyde/ 2.5% Glutaraldehyde in 0.1M sodium phosphate buffer</td><td>Electron Microscopy Sciences</td><td>15700 &amp;amp; 16300</td><td>Mixed in laboratory</td></tr><tr><td>50% Glutaraldehyde</td><td>Electron Microscopy Sciences</td><td>16300</td><td></td></tr><tr><td>0.25% Formvar</td><td>Electron Microscopy Sciences</td><td>15810</td><td></td></tr><tr><td>Copper Slot Grid</td><td>Electron Microscopy Sciences</td><td>M2010-CR</td><td></td></tr><tr><td>4% Osmium Tetroxide</td><td>Electron Microscopy Sciences</td><td>19140</td><td></td></tr><tr><td>Anti-SOD3 antibody</td><td>Abcam</td><td>Ab21974</td><td></td></tr><tr><td>Goat anti-rabbit Alexa Fluor 488</td><td>Invitrogen</td><td>A11070</td><td></td></tr><tr><td>Spurr&amp;rsquo;s embedding resin</td><td>Electron Microscopy Sciences</td><td>14300</td><td></td></tr></tbody></table>

mouse eye enucleation for remote high-throughput phenotyping

The mouse eye is an important genetic model for the translational study of human ophthalmic disease. Blinding diseases in humans, such as macular degeneration, photoreceptor degeneration, cataract, glaucoma, retinoblastoma, and diabetic retinopathy have been recapitulated in transgenic mice.1-5 Most transgenic and knockout mice have been generated by laboratories to study non-ophthalmic diseases, but genetic conservation between organ systems suggests that many of the same genes may also play a role in ocular development and disease. Hence, these mice represent an important resource for discovering new genotype-phenotype correlations in the eye. Because these mice are scattered across the globe, it is difficult to acquire, maintain, and phenotype them in an efficient, cost-effective manner. Thus, most high-throughput ophthalmic phenotyping screens are restricted to a few locations that require on-site, ophthalmic expertise to examine eyes in live mice. 6-9 An alternative approach developed by our laboratory is a method for remote tissue-acquisition that can be used in large or small-scale surveys of transgenic mouse eyes. Standardized procedures for video-based surgical skill transfer, tissue fixation, and shipping allow any lab to collect whole eyes from mutant animals and send them for molecular and morphological phenotyping. In this video article, we present techniques to enucleate and transfer both unfixed and perfusion fixed mouse eyes for remote phenotyping analyses.

Watch this Scientific Journal Video about Mouse Eye Enucleation for Remote High-throughput Phenotyping at JoVE.com

Mouse Eye Enucleation for Remote High-throughput Phenotyping

The dissection technique illustrates enucleation of the mouse eye for tissue fixation to perform phenotyping in high-throughput screens.

The mouse eye is an important genetic model for the translational study of human ophthalmic disease. Blinding diseases in humans, such as macular ...

mouse-eye-enucleation-for-remote-high-throughput-phenotyping

Research

JoVE Journal

Medicine

20.2K Views.  University of Iowa. De dissectie techniek illustreert enucleatie van de muis oog voor weefsel fixatie te fenotypering presteren in high-throughput-schermen.

Video: Mouse Eye Enucleation for Remote High-throughput Phenotyping

A Method for Lineage Tracing of Corneal Cells Using Multi-color Fluorescent Reporter Mice

Lineage tracing experiments define the origin, fate and behavior of cells in a specific tissue or organism. This technique has been successfully applied for many decades, revealing seminal findings in developmental biology. More recently, it was adopted by stem cell biologists to identify and track different stem cell populations with minimal experimental intervention. The recent developments in mouse genetics, the availability of a large number of mouse strains, and the advancements in fluorescent microscopy allow the straightforward design of powerful lineage tracing systems for various tissues with basic expertise, using commercially available tools. We have recently taken advantage of this powerful methodology to explore the origin and fate of stem cells at the ocular surface using R26R-Confetti mouse. This model offers a multi-color genetic system, for the expression of 4 fluorescent genes in a random manner. Here we describe the principles of this methodology and provide an adaptable protocol for designing lineage tracing experiments; specifically for the corneal epithelium as well as for other tissues.

In this article we describe the principles for designing and performing a multi-color lineage tracing experiment using R26R-Confetti mice. We provide a specific protocol for tracking corneal epithelial cells which can be modified for other tissues of interest.

Lineage tracing experiments define the origin, fate and behavior of cells in a specific tissue or organism. This technique has been successfully applied ...

Developmental Biology

Quantifying the Activity of cis-Regulatory Elements in the Mouse Retina by Explant Electroporation

Transcription factors within cellular gene networks control the spatiotemporal pattern and levels of expression of their target genes by binding to cis-regulatory elements (CREs), short (&tilde;300-600 bp) stretches of genomic DNA which can lie upstream, downstream, or within the introns of the genes they control. CREs (i.e., enhancers/promoters) typically consist of multiple clustered binding sites for both transcriptional activators and repressors1-3. They serve as logical integrators of transcriptional input giving a unitary output in the form of spatiotemporally precise and quantitatively exact promoter activity. Most studies of mammalian cis-regulation to date have relied on mouse transgenesis as a means of assaying the enhancer function of CREs4-5. This technique is time-consuming, costly and, on account of insertion site effects, largely non-quantitative. On the other hand, quantitative assays for mammalian CRE function have been developed in tissue culture systems (e.g., dual luciferase assays), but the in vivo relevance of these results is often uncertain. 
Electroporation offers an excellent alternative to traditional mouse transgenesis in that it permits both spatiotemporal and quantitative assessment of cis-regulatory activity in living mammalian tissue. This technique has been particularly useful in the analysis of cis-regulation in the central nervous system, especially in the cerebral cortex and the retina6-8. While mouse retinal electroporation, both in vivo and ex vivo, has been developed and extensively described by Matsuda and Cepko6-7,9, we have recently developed a simple approach to quantify the activity of photoreceptor-specific CREs in electroporated mouse retinas10. Given that the amount of DNA that is introduced into the retina by electroporation can vary from experiment to experiment, it is necessary to include a co-electroporated 'loading control' in all experiments. In this respect, the technique is very similar to the dual luciferase assay used to quantify promoter activity in cultured cells. 
When assaying photoreceptor cis-regulatory activity, electroporation is usually performed in newborn mice (postnatal day 0, P0) which is the time of peak rod production11-12. Once retinal cell types become post-mitotic, electroporation is much less efficient. Given the high rate of rod birth in newborn mice and the fact that rods constitute more than 70% of the cells in the adult mouse retina, the majority of cells that are electroporated at P0 are rods. For this reason, rod photoreceptors are the easiest retinal cell type to study via electroporation. The technique we describe here is primarily useful for quantifying the activity of photoreceptor CREs.

Quantifying the Activity of cis-Regulatory Elements in the Mouse Retina by Explant Electroporation

This protocol describes a simple and inexpensive way to quantify the activity of cis-regulatory elements (i.e., enhancer/promoters) in living mouse retinas via explant electroporation. DNA preparation, retinal dissection, electroporation, retinal explant culture, and post-fixation analysis and quantification are described.

Transcription factors within cellular gene networks control the spatiotemporal pattern and levels of expression of their target genes by binding to ...

Neuroscience

A Protocol to Evaluate and Quantify Retinal Pigmented Epithelium Pathologies in Mouse Models of Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is a debilitating retinal disorder in aging populations. It is widely believed that dysfunction of the retinal pigmented epithelium (RPE) is a key pathobiological event in AMD. To understand the mechanisms that lead to RPE dysfunction, mouse models can be utilized by researchers. It has been established by previous studies that mice can develop RPE pathologies, some of which are observed in the eyes of individuals diagnosed with AMD. Here, we describe a phenotyping protocol to assess RPE pathologies in mice. This protocol includes the preparation and evaluation of retinal cross-sections using light microscopy and transmission electron microscopy, as well as that of RPE flat mounts by confocal microscopy. We detail the common types of murine RPE pathologies observed by these techniques and ways to quantify them through unbiased methods for statistical testing. As proof of concept, we use this RPE phenotyping protocol to quantify the RPE pathologies observed in mice overexpressing transmembrane protein 135 (Tmem135) and aged wild-type C57BL/6J mice. The main goal of this protocol is to present standard RPE phenotyping methods with unbiased quantitative assessments for scientists using mouse models of AMD.

Mouse models can be useful tools for investigating the biology of the retinal pigmented epithelium (RPE). It has been established that mice can develop an array of RPE pathologies. Here, we describe a phenotyping protocol to elucidate and quantify RPE pathologies in mice using light, transmission electron, and confocal microscopy.

Age-related macular degeneration (AMD) is a debilitating retinal disorder in aging populations. It is widely believed that dysfunction of the retinal ...

Genetics

Isolation of Murine Retinal Endothelial Cells for Next-Generation Sequencing

Recent improvements in next-generation sequencing have advanced researchers&#39; knowledge of molecular and cellular biology, with several studies revealing novel paradigms in vascular biology. Applying these methods to models of vascular development requires the optimization of cell isolation techniques from embryonic and postnatal tissues. Cell yield, viability, and purity all need to be maximal to obtain accurate and reproducible results from next-generation sequencing approaches. The neonatal mouse retinal vascularization model is used by researchers to study mechanisms of vascular development. Researchers have used this model to investigate mechanisms of angiogenesis and arterial-venous fate specification during blood vessel formation and maturation. Applying next-generation sequencing techniques to study the retinal vascular development model requires optimization of a method for the isolation of retinal endothelial cells that maximizes cell yield, viability, and purity. This protocol describes a method for murine retinal tissue isolation, digestion, and purification using fluorescence-activated cell sorting (FACS). The results indicate that the FACS-purified CD31+/CD45- endothelial cell population is highly enriched for endothelial cell gene expression and exhibits no change in viability for 60 min post-FACS. Included are representative results of next-generation sequencing approaches on endothelial cells isolated using this method, including bulk RNA sequencing and single-cell RNA sequencing, demonstrating that this method for retinal endothelial cell isolation is compatible with next-generation sequencing applications. This method of retinal endothelial cell isolation will allow for advanced sequencing techniques to reveal novel mechanisms of vascular development.

This protocol describes a method for the isolation of murine postnatal retinal endothelial cells optimized for cell yield, purity, and viability. These cells are suitable for next-generation sequencing approaches.

Recent improvements in next-generation sequencing have advanced researchers&#39; knowledge of molecular and cellular biology, with several studies ...

Optical Coherence Tomography: Imaging Mouse Retinal Ganglion Cells In Vivo

Structural changes in the retina are common manifestations of ophthalmic diseases. Optical coherence tomography (OCT) enables their identification in vivo&#8212;rapidly, repetitively, and at a high resolution. This protocol describes OCT imaging in the mouse retina as a powerful tool to study optic neuropathies (OPN). The OCT system is an interferometry-based, non-invasive alternative to common post mortem histological assays. It provides a fast and accurate assessment of retinal thickness, allowing the possibility to track changes, such as retinal thinning or thickening. We present the imaging process and analysis with the example of the Opa1delTTAG mouse line. Three types of scans are proposed, with two quantification methods: standard and homemade calipers. The latter is best for use on the peripapillary retina during radial scans; being more precise, is preferable for analyzing thinner structures. All approaches described here are designed for retinal ganglion cells (RGC) but are easily adaptable to other cell populations. In conclusion, OCT is efficient in mouse model phenotyping and has the potential to be used for the reliable evaluation of therapeutic interventions.

Optical Coherence Tomography: Imaging Mouse Retinal Ganglion Cells In Vivo

This manuscript describes a protocol for the in vivo imaging of the mouse retina with high-resolution spectral domain optical coherence tomography (SD-OCT). It focuses on retinal ganglion cells (RGC) in the peripapillary region, with several scanning and quantifying approaches described.

Structural changes in the retina are common manifestations of ophthalmic diseases. Optical coherence tomography (OCT) enables their identification in ...

A Custom Multiphoton Microscopy Platform for Live Imaging of Mouse Cornea and Conjunctiva

Conventional histological analysis and cell culture systems are insufficient to simulate in vivo physiological and pathological dynamics completely. Multiphoton microscopy (MPM) has become one of the most popular imaging modalities for biomedical study at cellular levels in vivo, advantages include high resolution, deep tissue penetration and minimal phototoxicity. We have designed an MPM imaging platform with a customized mouse eye holder and a stereotaxic stage for imaging ocular surface in vivo. Dual fluorescent protein reporter mouse enables visualization of cell nuclei, cell membranes, nerve fibers, and capillaries within the ocular surface. In addition to multiphoton fluorescence signals, acquiring second harmonic generation (SHG) simultaneously allows for the characterization of collagenous stromal architecture. This platform can be employed for intravital imaging with accurate positioning across the entire ocular surface, including cornea and conjunctiva.

Presented here is a multiphoton microscopic platform for live mouse ocular surface imaging. Fluorescent transgenic mouse enables the visualization of cell nuclei, cell membranes, nerve fibers and capillaries within the ocular surface. Non-linear second harmonic generation signals derived from collagenous structures provide label-free imaging for stromal architectures.

Conventional histological analysis and cell culture systems are insufficient to simulate in vivo physiological and pathological dynamics completely. ...

Bioengineering

Ultrahigh Resolution Mouse Optical Coherence Tomography to Aid Intraocular Injection in Retinal Gene Therapy Research

HR-SD-OCT is utilized to monitor the progression of photoreceptor degeneration in live mouse models, assess the delivery of therapeutic agents into the subretinal space, and to evaluate toxicity and efficacy in vivo. HR-SD-OCT uses near infrared light (800-880 nm) and has optics specifically designed for the unique optics of the mouse eye with sub-2-micron axial resolution. Transgenic mouse models of outer retinal (photoreceptor) degeneration and controls were imaged to assess the disease progression. Pulled glass microneedles were used to deliver sub retinal injections of adeno-associated virus (AAV) or nanoparticles (NP) via a trans-scleral and trans-choroidal approach. Careful positioning of the needle into the subretinal space was required prior to a calibrated pressure injection, which delivers fluid into the sub retinal space. Real time subretinal surgery was conducted on our retinal imaging system (RIS). HR-SD-OCT demonstrated progressive uniform retinal degeneration due to expression of a toxic mutant human mutant rhodopsin (P347S) (RHOP347S) transgene in mice. HR-SD-OCT allows rigorous quantification of all the retinal layers. Outer nuclear layer (ONL) thickness and photoreceptor outer segment length (OSL) measurements correlate with photoreceptor vitality, degeneration, or rescue. The RIS delivery system allows real-time visualization of subretinal injections in neonatal (~P10-14) or adult mice, and HR-SD-OCT immediately determines success of delivery and maps areal extent. HR-SD-OCT is a powerful tool that can evaluate the success of subretinal surgery in mice, in addition to measuring vitality of photoreceptors in vivo. HR-SD-OCT can also be used to identify uniform animal cohorts to evaluate the extent of retinal degeneration, toxicity, and therapeutic rescue in preclinical gene therapy research studies.

Here we demonstrate a novel approach to using high resolution spectral-domain optical coherence tomography (HR-SD-OCT) to assist delivery of gene therapy agents into the subretinal space, assess its areal coverage, and characterize photoreceptor vitality.

HR-SD-OCT is utilized to monitor the progression of photoreceptor degeneration in live mouse models, assess the delivery of therapeutic agents into the ...

Transpupillary Two-Photon In Vivo Imaging of the Mouse Retina

The retina transforms light signals from the environment into electrical signals that are propagated to the brain. Diseases of the retina are prevalent and cause visual impairment and blindness. Understanding how such diseases progress is critical to formulating new treatments. In vivo&#160;microscopy in animal models of disease is a powerful tool for understanding neurodegeneration and has led to important progress towards treatments of conditions ranging from Alzheimer&#39;s disease to stroke. Given that the retina is the only central nervous system structure inherently accessible by optical approaches, it naturally lends itself towards in vivo imaging. However, the native optics of the lens and cornea present some challenges for effective imaging access.
This protocol outlines methods for in vivo two-photon imaging of cellular cohorts and structures in the mouse retina at cellular resolution, applicable for both acute- and chronic-duration imaging experiments. It presents examples of retinal ganglion cell (RGC), amacrine cell, microglial, and vascular imaging using a suite of labeling techniques including adeno-associated virus (AAV) vectors, transgenic mice, and inorganic dyes. Importantly, these techniques extend to all cell types of the retina, and suggested methods for accessing other cellular populations of interest are described. Also detailed are example strategies for manual image postprocessing for display and quantification. These techniques are directly applicable to studies of retinal function in health and disease.

In vivo imaging is a powerful tool for the study of biology in health and disease. This protocol describes transpupillary imaging of the mouse retina with a standard two-photon microscope. It also demonstrates different in vivoimaging methods to fluorescently label multiple cellular cohorts of the retina.

The retina transforms light signals from the environment into electrical signals that are propagated to the brain. Diseases of the retina are prevalent ...

A Highly Reproducible and Straightforward Method to Perform In Vivo Ocular Enucleation in the Mouse after Eye Opening

Enucleation or the surgical removal of an eye can generally be considered as a model for nerve deafferentation. It provides a valuable tool to study the different aspects of visual, cross-modal and developmental plasticity along the mammalian visual system1-4.
Here, we demonstrate an elegant and straightforward technique for the removal of one or both eyes in the mouse, which is validated in mice of 20 days old up to adults. Briefly, a disinfected curved forceps is used to clamp the optic nerve behind the eye. Subsequently, circular movements are performed to constrict the optic nerve and remove the eyeball. The advantages of this technique are high reproducibility, minimal to no bleeding, rapid post-operative recovery and a very low learning threshold for the experimenter. Hence, a large amount of animals can be manipulated and processed with minimal amount of effort. The nature of the technique may induce slight damage to the retina during the procedure. This side effect makes this method less suitable as compared to Mahajan et al. (2011)5 if the goal is to collect and analyze retinal tissue. Also, our method is limited to post-eye opening ages (mouse: P10 - 13 onwards) since the eyeball needs to be displaced from the socket without removing the eyelids. The in vivo enucleation technique described in this manuscript has recently been successfully applied with minor modifications in rats and appears useful to study the afferent visual pathway of rodents in general.

A Highly Reproducible and Straightforward Method to Perform In Vivo Ocular Enucleation in the Mouse after Eye Opening

The removal of eyes, also called enucleation, provides a useful strategy to study aspects of visual, cross-modal, and developmental plasticity along the mammalian visual system since it induces irreversible partial (monocular) or complete (binocular) vision loss. Here we describe a highly reproducible and straightforward approach to perform in vivo enucleation.

Enucleation or the surgical removal of an eye can generally be considered as a model for nerve deafferentation. It provides a valuable tool to study the ...

Biology

Microdissection of the Rodent Eye

The ocular micro-dissection of the rodent eye involves the segmentation of the enucleated eyeball with the attached nictitating membrane, or third eyelid, to obtain the anterior and posterior eyecups. With this technique, the sub-parts of the eye, including the corneal tissue, neural tissue, retinal pigment epithelial (RPE) tissue, and lens, can be obtained for wholemounts, cryo-sectioning, and/or single-cell suspensions of a specific ocular tissue. The presence of the third eyelid presents unique and significant advantages, as it benefits the maintenance of the orientation of the eye, which is important for understanding eye physiology following any localized intervention or in studies involving ocular analysis relating to the eye&#39;s spatial topography.
In this method, we enucleated the eyeball at the socket along with the third eyelid by carefully and slowly cutting through the extraocular muscles and severing the optic nerve. The eyeball was pierced through the corneal limbus using a microblade.&#160;The incision was used as the point of entry, allowing for cutting along the corneal-scleral junction by inserting micro-scissors through the incision point. Small and continuous cuts along the circumference were made until the cups separated. These could be further dissected by gently peeling the translucent layer of the neural retina using Colibri suturing forceps to obtain the neural retina and RPE layers. Further, three/four equidistant cuts were made from the periphery perpendicularly to the optic center until the optic nerve was reached. This opened the hemispherical cups into a floret shape so that they fell flat and could be easily mounted. This technique has been used in our lab for corneal wholemounts and retinal sections. The presence of the third eyelid delineates the nasal-temporal orientation, which allows for the study of various cell therapy interventions post-transplantation and, thus, the targeted physiological validation vital for visualization and accurate representation in such studies.

This paper presents a protocol for ocular micro-dissection in rodents. The process involves the enucleation of the eyeball along with the nictitating membrane (i.e., the third eyelid). This is then followed by the separation of the posterior and anterior eye cups.

The ocular micro-dissection of the rodent eye involves the segmentation of the enucleated eyeball with the attached nictitating membrane, or third eyelid, ...

Mouse Eye Enucleation for Remote High-throughput Phenotyping

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