Name: the corneal micropocket assay: a model of angiogenesis in the mouse eye
Uploaded: 2014-08-16T17:00:00
Description: Watch this Scientific Journal Video about The Corneal Micropocket Assay: A Model of Angiogenesis in the Mouse Eye at JoVE.com

We thank Kristin Johnson for the graphic work.

All protocols involving animals are presented to and approved by the Institutional Animal Care and Use Committee at Children&#39;s Hospital Boston and are conducted in accordance with the recommendations of the Association for Assessment and Accreditation of Laboratory Animal Care (AAALAC). Be sure to use sterile instrumentation and aseptic techniqure while performing the procedure.&#160;
1. Preparation of Pellets
<ol>
	<li>Weigh out 10 mg of sucralfate and 60 mg of hydron with the sterile un...

<ol>
	<li>Gospodarowicz, D., Moran, J., Braun, D., Birdwell, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Clonal+growth+of+bovine+vascular+endothelial+cells:+fibroblast+growth+factor+as+a+survival+agent.">Clonal growth of bovine vascular endothelial cells: fibroblast growth factor as a survival agent.</a> Proc. Natl. Acad. Sci. USA. 73, 4120-4124 (1976).</li><li>Glaser, B. M., D'Amore, P. A., Seppa, H., Seppa, S., Schiffmann, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adult+tissues+contain+chemoattractants+for+vascular+endothelial+cells.">Adult tissues contain chemoattractants for vascular endothelial cells.</a> Nature. 288, 483-484 (1980).</li><li>Kubota, Y., Kleinman, H. K., Martin, G. R., Lawley, T. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+laminin+and+basement+membrane+in+the+morphological+differentiation+of+human+endothelial+cells+into+capillary-like+structures.">Role of laminin and basement membrane in the morphological differentiation of human endothelial cells into capillary-like structures.</a> J. Cell Biol. 107, 1589-1598 (1988).</li><li>Montesano, R., Orci, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tumor-promoting+phorbol+esters+induce+angiogenesis+in+vitro.">Tumor-promoting phorbol esters induce angiogenesis in vitro.</a> Cell. 42, 469-477 (1985).</li><li>Korff, T., Augustin, H. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Integration+of+endothelial+cells+in+multicellular+spheroids+prevents+apoptosis+and+induces+differentiation.">Integration of endothelial cells in multicellular spheroids prevents apoptosis and induces differentiation.</a> J. Cell Biol. 143, 1341-1352 (1998).</li><li>Nicosia, R. F., Tchao, R., Leighton, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Histotypic+angiogenesis+in+vitro:+light+microscopic,+ultrastructural,+and+radioautographic+studies.">Histotypic angiogenesis in vitro: light microscopic, ultrastructural, and radioautographic studies.</a> In Vitro. 18, 538-549 (1982).</li><li>Wong, K. H., Chan, J. M., Kamm, R. D., Tien, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidic+models+of+vascular+functions.">Microfluidic models of vascular functions.</a> Annu Rev Biomed Eng. 14, 205-230 (2012).</li><li>Sandison, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+method+for+the+microscopic+study+of+living+growing+tissues+by+the+introduction+of+a+transparent+chamber+in+the+rabbit's+ear.">A new method for the microscopic study of living growing tissues by the introduction of a transparent chamber in the rabbit's ear.</a> Anat. Rec. 28, 281-287 (1924).</li><li>Jain, R. K., Schlenger, K., Hockel, M., Yuan, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+angiogenesis+assays:+progress+and+problems.">Quantitative angiogenesis assays: progress and problems.</a> Nat. Med. 3, 1203-1208 (1997).</li><li>Rogers, M. S., Birsner, A. E., D'Amato, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+mouse+cornea+micropocket+angiogenesis+assay.">The mouse cornea micropocket angiogenesis assay.</a> Nat. Protoc. 2 (10), 2545-2550 (2007).</li><li>Gimbrone, M. A., Leapman, S. B., Cotran, R. S., Folkman, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tumor+dormancy+in+vivo+by+prevention+of+neovascularization.">Tumor dormancy in vivo by prevention of neovascularization.</a> J. Exp. Med. 136, 261-276 (1972).</li><li>Gimbrone, M. A., Cotran, R. S., Leapman, S. B., Folkman, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tumor+growth+and+neovascularization:+an+experimental+model+using+the+rabbit+cornea.">Tumor growth and neovascularization: an experimental model using the rabbit cornea.</a> J. Natl. Cancer Inst. 52, 413-427 (1974).</li><li>Rohan, R. M., Fernandez, A., Udagawa, T., Yuan, J., D'Amato, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetic+heterogeneity+of+angiogenesis+in+mice.">Genetic heterogeneity of angiogenesis in mice.</a> FASEB J. 14 (7), 871-876 (2000).</li><li>Chang, L. K., 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=Dose-dependent+response+of+FGF-2+for+lymphangiogenesis.">Dose-dependent response of FGF-2 for lymphangiogenesis.</a> Proc Natl Acad Sci U S A. 101 (32), 11658-11663 (2004).</li><li>Udagawa, T., Birsner, A. E., Wood, M., D'Amato, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chronic+suppression+of+angiogenesis+following+radiation+exposure+is+independent+of+hematopoietic+reconstitution.">Chronic suppression of angiogenesis following radiation exposure is independent of hematopoietic reconstitution.</a> Cancer Res. 67 (5), 2040-2045 (2007).</li><li>Turner, P. V., Albassam, 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=Susceptibility+of+rats+to+corneal+lesions+after+injectable+anesthesia.">Susceptibility of rats to corneal lesions after injectable anesthesia.</a> Med Comp. 55 (2), 175-182 (2005).</li><li>Calderone, L., Grimes, P., Shalev, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Acute+reversible+cataract+induced+by+xylazine+and+by+ketamine-xylazine+anesthesia+in+rats+and+mice.">Acute reversible cataract induced by xylazine and by ketamine-xylazine anesthesia in rats and mice.</a> Exp. Eye Res. 42, 331-337 (1986).</li></ol>

There are several critical steps in performing a successful corneal assay.&#160; The first is making uniform pellets capable of being implanted and stimulating vessels.&#160; The most important parts of pellet preparation are 1) using carrier-free growth factor; 2) ensuring a good mixture of growth factor with the sucralfate and hydron and 3) moving the final mixture swiftly but carefully from the eppendorf tube to the mesh where the pellets are cast.&#160; It is recommended that &#34;dummy&#34; pellets be made without g...

The process of angiogenesis, the formation of new blood vessels form preexisting ones, is highly complex and is regulated by several endogenous factors that control different steps of vessel sprouting and morphogenesis.&#160; Angiogenesis is triggered due to a shift in balance between pro- and anti-angiogenic factors, a balance that normally maintains the vasculature in a quiescent state.&#160; Angiogenesis in adults occurs in certain physiological conditions such as during the female ovarian cycle or in repair processes such as wound healing and tissue regeneration. &#160;However, it is also a hallmark of several pathologies including malignancies, autoimmune conditions and inflammatory diseases. &#160;The involvement of angiogenesis in these physiological and pathological conditions makes it an important subject for research and an attractive target for therapy.
Due to the complexity of angiogenesis and the involvement of several cells and factors in the process, including endothelial cells, pericytes, circulating cells and stromal cells, in vitro models remain limited and cannot recapitulate the unique in vivo microenvironment.&#160; &#160;The main in vitro assays of angiogenesis are largely focused on observing direct effects on endothelial cells and measuring certain steps in angiogenic process under controlled conditions. These assays include the quantification of endothelial cell proliferation1, migration2, network formation3, tube formation4 and sprouting from spheroids5. &#160;Ex vivo models, unlike the in vitro ones, are more complex and incorporate multiple tissue cell types, an example being the aortic ring assay6.&#160; Nevertheless, like other systems, it cannot capture the contribution of circulating cells and the natural stroma of endothelial cells as exists in vivo.&#160; Attempts to study angiogenesis under flow to mimic the in vivo setting are performed using microfluidic systems7, however even these assays, although much improved, are still unable to account for all the compartments existing in vivo.
Due to the limitations of the in vitro and ex vivo angiogenesis models, in vivo models remain the more reliable choices for angiogenesis studies.&#160; Examples of these models include the implantation of transparent chambers, &#34;windows&#34;, that allow the visualization of growing blood vessels under microscope8, injectable subcutaneous implants such as matrigel and vessel formation in normal tissues such as mouse ear and the chicken chorioallantoic membrane (CAM).&#160; However, one of the most acceptable and quantitative in vivo angiogenesis models is the corneal micropocket neovascularization assay described here, which exploits the naturally avascular cornea as a &#34;screen&#34; to visualize and assess new angiogenic growth9.
Here we describe the corneal micropocket assay as developed in mice.&#160; Initially the model was used to measure nonspecific angiogenic stimuli in rabbit corneas. This was done by introducing tumor pieces into the aqueous humor of the anterior chamber of the rabbit eye and measured tumor-induced neovascularization11.
&#160;However, the assay was later evolved to study effects of specific growth factors10 to better specify and standardize the angiogenic effect.&#160;&#160; In order to release the growth factor in the eye, slow-release pellets containing known quantities of angiogenic growth factors were used instead of tissues.&#160; The availability of purified recombinant angiogenic proteins such as bFGF or VEGF enabled their use as specific targets of angiogenesis modulaters12.&#160; Initially, the assay was largely used in rabbits, which are easier to work with due to their size but later the model was translated into mice; a smaller and less expensive animal model.&#160; Shifting from rabbit to mice provided an important advantage of being able to use genetically manipulated animals, thereby creating a new area of research into the genetic components impacting angiogenesis13.&#160; In addition to the more acceptable usage of cornea assay in studying angiogenesis, other biological processes can also being investigated using modified assays.&#160; For example, studies of lymphangiogenesis were made possible through the implantation of low dose bFGF pellets which allowed the visualization of lymphatic vessels through specific molecular markers14.&#160; In addition, this assay has provided a means to evaluate the effects of radiation on angiogenesis15.
In summation, the corneal micropocket angiogenesis assay is a quantitative, reproducible, flexible assessment of angiogenesis in vivo.&#160; A major advantage of this assay is that the measurement of background vessels is unnecessary because the vessels grow on a naturally avascular tissue.&#160; We describe here the protocol of this assay in details and discuss different scenarios which can occur. The assay consists of 3 discrete segments.&#160; Here we will describe the preparation of growth factor-inclusive pellets, the subsequent surgical implantation and finally the method used to quantify the resulting neovascular growth.

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			<td height="21" style="height:21px;width:216px;">Section 1: Pellet preparation</td>
			<td style="width:111px;"></td>
			<td style="width:119px;"></td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Sucralfate</td>
			<td style="width:111px;">Sigma</td>
			<td style="width:119px;">#S0652</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Hydron (aka Poly(2-Hema))</td>
			<td style="width:111px;">Sigma</td>
			<td style="width:119px;">#P3932-10G</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Ethanol</td>
			<td style="width:111px;">Pharmco Products Inc</td>
			<td style="width:119px;">#111000200CSGL</td>
			<td></td>
		</tr>
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			<td height="21" style="height:21px;width:216px;">Growth factors:</td>
			<td style="width:111px;"></td>
			<td style="width:119px;"></td>
			<td>Must be carrier-free (no bovine serum albumin(BSA))</td>
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			<td height="21" style="height:21px;width:216px;">&#160;Fibroblast growth factor (FGF)</td>
			<td style="width:111px;">PeproTech</td>
			<td style="width:119px;">#AF-100-18B</td>
			<td></td>
		</tr>
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			<td height="42" style="height:42px;width:216px;">Vascular endothelial growth factor (VEGF)</td>
			<td style="width:111px;">R &#38; D Systems</td>
			<td style="width:119px;">#293-VE-050/CF</td>
			<td></td>
		</tr>
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			<td height="21" style="height:21px;width:216px;">35 mm dish</td>
			<td style="width:111px;">Becton-Dickson</td>
			<td style="width:119px;">#353001</td>
			<td>Used for storage of pellets</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">10 cm petri dish</td>
			<td style="width:111px;">VWR</td>
			<td style="width:119px;">#25384-342</td>
			<td>Used as work surface for preparing pellets</td>
		</tr>
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			<td height="21" style="height:21px;width:216px;">Mesh</td>
			<td style="width:111px;">Sefar America</td>
			<td style="width:119px;">#03--300/51</td>
			<td>300 um nitex nylon, cut into cm square pieces and sterilzed in autoclave</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Spatulas</td>
			<td style="width:111px;">Fisher Scientific</td>
			<td style="width:119px;">#21-401-10</td>
			<td>Use tapered end of one to break up pellet mixture. Bend tapered end of other to help remove mixture from microcentrifuge tube.</td>
		</tr>
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			<td height="21" style="height:21px;width:216px;">Microcentrifuge tubes</td>
			<td style="width:111px;">Fisher Scientific</td>
			<td style="width:119px;">#05-408-146</td>
			<td>One for hydron, one for sucralfate</td>
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			<td height="21" style="height:21px;width:216px;">Jewelers forceps, #5</td>
			<td style="width:111px;">Ambler Surgical</td>
			<td style="width:119px;">#2315E</td>
			<td>Need 2 for pulling mesh apart</td>
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			<td height="42" style="height:42px;width:216px;">Centrifugal evaporator</td>
			<td style="width:111px;">ThermoSavant</td>
			<td style="width:119px;">DNA110 SpeedVac</td>
			<td></td>
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			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:111px;"></td>
			<td style="width:119px;"></td>
			<td></td>
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			<td height="42" style="height:42px;width:216px;">Section 2: Surgical implantation of pellets</td>
			<td style="width:111px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
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			<td height="21" style="height:21px;width:216px;">Operating microscope</td>
			<td style="width:111px;">Zeiss</td>
			<td style="width:119px;"></td>
			<td></td>
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			<td height="21" style="height:21px;width:216px;">2.5% Avertin</td>
			<td style="width:111px;"></td>
			<td style="width:119px;"></td>
			<td>General anesthetic</td>
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			<td height="42" style="height:42px;width:216px;">Proparacaine hydrochloride ophthalmic solution 0.5%</td>
			<td style="width:111px;">Falcon</td>
			<td>NDC# 6131401601</td>
			<td>Eye anesthetic</td>
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			<td height="42" style="height:42px;width:216px;">Triple Antibiotic Ophthalmic Ointment</td>
			<td style="width:111px;">Bausch &#38; Lomb</td>
			<td style="width:119px;">NDC# 2420878055</td>
			<td>Contains neomycin, polymixin and bacitracin</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Ophthalmic microknife, 5 mm</td>
			<td style="width:111px;">Surgistar</td>
			<td style="width:119px;">#924501</td>
			<td>30 degree angle</td>
		</tr>
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			<td height="21" style="height:21px;width:216px;">von Graef knife</td>
			<td style="width:111px;">Ambler Surgical</td>
			<td style="width:119px;">#3401E</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Jewelers forceps, #1</td>
			<td style="width:111px;">Ambler Surgical</td>
			<td style="width:119px;">#2301E</td>
			<td>Must be blunted with sharpening stone for proptosing eye</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Jewelers forceps, #5</td>
			<td style="width:111px;">Ambler Surgical</td>
			<td style="width:119px;">#2305E</td>
			<td>For picking up pellets and placing on eye</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Small curved scissors</td>
			<td style="width:111px;">Ambler Surgical</td>
			<td style="width:119px;">#5636E</td>
			<td>For trimming whiskers</td>
		</tr>
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			<td height="21" style="height:21px;width:216px;">Gauze</td>
			<td style="width:111px;"></td>
			<td style="width:119px;"></td>
			<td>For blotting eye after proparacaine</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:111px;"></td>
			<td style="width:119px;"></td>
			<td></td>
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			<td height="42" style="height:42px;width:216px;">Section 3: Grading of Corneal Neovascularization</td>
			<td style="width:111px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">2.5% Avertin</td>
			<td style="width:111px;"></td>
			<td style="width:119px;"></td>
			<td>General anesthetic</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Slit lamp</td>
			<td style="width:111px;">Nikon</td>
			<td style="width:119px;">FS-2</td>
			<td>Needs an ocular with a reticule to assist in measuring</td>
		</tr>
	</tbody>
</table>

the corneal micropocket assay: a model of angiogenesis in the mouse eye

The mouse corneal micropocket assay is a robust and quantitative in vivo assay for evaluating angiogenesis. By using standardized slow-release pellets containing specific growth factors that trigger blood vessel growth throughout the naturally avascular cornea, angiogenesis can be measured and quantified. In this assay the angiogenic response is generated over the course of several days, depending on the type and dose of growth factor used. The induction of neovascularization is commonly triggered by either basic fibroblast growth factor (bFGF) or vascular endothelial growth factor (VEGF). By combining these growth factors with sucralfate and hydron (poly-HEMA (poly(2-hydroxyethyl methacrylate))) and casting the mixture into pellets, they can be surgically implanted in the mouse eye. These uniform pellets slowly-release the growth factors over five or six days (bFGF or VEGF respectively) enabling sufficient angiogenic response required for vessel area quantification using a slit lamp. This assay can be used for different applications, including the evaluation of angiogenic modulator drugs or treatments as well as comparison between different genetic backgrounds affecting angiogenesis. A skilled investigator after practicing this assay can implant a pellet in less than 5 min per eye.

Typical results for bFGF and VEGF pellets in the normal low angiogenic C57BL/6J mice are shown in Figure 2A and B, respectively.&#160; Figure 2E shows the normal distribution of vessel area (VA) in the C57BL/6J strain with varying doses of these growth factors.&#160; 80 ng bFGF pellets normally result in a VA of approximately 2.0 mm2, though values in a range of 1.8-2.4 mm2 are acceptable.&#160; 200 ng VEGF pellets typically cause a response of appr...

Watch this Scientific Journal Video about The Corneal Micropocket Assay: A Model of Angiogenesis in the Mouse Eye at JoVE.com

The Corneal Micropocket Assay: A Model of Angiogenesis in the Mouse Eye

The protocol describes the corneal micropocket assay as developed in mice.

The mouse corneal micropocket assay is a robust and quantitative in vivo assay for evaluating angiogenesis. By using standardized slow-release pellets ...

the-corneal-micropocket-assay-a-model-of-angiogenesis-in-the-mouse-eye

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Isolation and expansion of the putative neural stem cells (NSCs) from the adult murine brain was first described by Reynolds and Weiss in 1992 employing a chemically defined serum-free culture system known as the neurosphere assay (NSA). In this assay, the majority of differentiated cell types die within a few days of culture but a small population of growth factor responsive precursor cells undergo active proliferation in the presence of epidermal growth factor (EGF) and/ basic fibroblastic growth factor (bFGF). These cells form colonies of undifferentiated cells called neurospheres, which in turn can be subcultured to expand the pool of neural stem cells. Moreover, the cells can be induced to differentiate, generating the three major cell types of the CNS i.e. neurons, astrocytes, and oligodendrocytes. This assay provides an invaluable tool to supply a consistent, renewable source of undifferentiated CNS precursors, which could be used for in vitro studies and also for therapeutic purposes.
This video demonstrates the NSA method to generate and expand NSCs from the adult mouse periventricular region, and provides technical insights to ensure one can achieve reproducible neurosphere cultures. The procedure includes harvesting the brain from the adult mouse, micro-dissection of the periventricular region, tissue preparation and culture in the NSA. The harvested tissue is first chemically digested using trypsin-EDTA and then mechanically dissociated in NSC medium to achieve a single cell suspension and finally plated in the NSA. After 7-10 days in culture, the resulting primary neurospheres are ready for subculture to reach the amount of cells required for future experiments.

This video protocol demonstrates the neurosphere assay method to generate and expand neural stem cells from the adult mouse periventricular region, and provides technical insights to ensure one can achieve reproducible neurosphere cultures.

Isolation and expansion of the putative neural stem cells (NSCs) from the adult murine brain was first described by Reynolds and Weiss in 1992 employing a ...

Establishing Embryonic Mouse Neural Stem Cell Culture Using the Neurosphere Assay

In mammalians, stem cells acts as a source of undifferentiated cells to maintain cell genesis and renewal in different tissues and organs during the life span of the animal. They can potentially replace cells that are lost in the aging process or in the process of injury and disease. The existence of neural stem cells (NSCs) was first described by Reynolds and Weiss (1992) in the adult mammalian central nervous system (CNS) using a novel serum&#8208;free culture system, the neurosphere assay (NSA). Using this assay, it is also feasible to isolate and expand NSCs from different regions of the embryonic CNS. These in vitro expanded NSCs are multipotent and can give rise to the three major cell types of the CNS. While the NSA seems relatively simple to perform, attention to the procedures demonstrated here is required in order to achieve reliable and consistent results. This video practically demonstrates NSA to generate and expand NSCs from embryonic day 14-mouse brain tissue and provides technical details so one can achieve reproducible neurosphere cultures. The procedure includes harvesting E14 mouse embryos, brain microdissection to harvest the ganglionic eminences, dissociation of the harvested tissue in NSC medium to gain a single cell suspension, and finally plating cells in NSA culture. After 5-7 days in culture, the resulting primary neurospheres are passaged to further expand the number of the NSCs for future experiments.

This video protocol demonstrates the application of the neurosphere assay for the isolation and expansion of neural stem cells from the ganglionic eminences of embryonic day 14-mouse brain.

In mammalians, stem cells acts as a source of undifferentiated cells to maintain cell genesis and renewal in different tissues and organs during the life ...

Dissection of a Mouse Eye for a Whole Mount of the Retinal Pigment Epithelium

The retinal pigment epithelium (RPE) lies at the back of the mammalian eye, just under the neural retina, which contains the photoreceptors (rods and cones). The RPE is a monolayer of pigmented cuboidal cells and associates closely with the neural retina just above it. This association makes the RPE of great interest to researchers studying retinal diseases. The RPE is also the site of an in vivo assay of homology-directed DNA repair, the pun assay. The mouse eye is particularly difficult to dissect due to its small size (about 3.5mm in diameter) and its spherical shape. This article demonstrates in detail a procedure for dissection of the eye resulting in a whole mount of the RPE. In this procedure, we show how to work with, rather than against, the spherical structure of the eye. Briefly, the connective tissue, muscle, and optic nerve are removed from the back of the eye. Then, the cornea and lens are removed. Next, strategic cuts are made that result in significant flattening of the remaining tissue. Finally, the neural retina is gently lifted off, revealing an intact RPE, which is still attached to the underlying choroid and sclera. This whole mount can be used to perform the pun assay or for immunohistochemistry or immunofluorescent assessment of the RPE tissue.

A formal demonstration of the dissection of a mouse eye, resulting in a whole mount of the retinal pigment epithelium.

The retinal pigment epithelium (RPE) lies at the back of the mammalian eye, just under the neural retina, which contains the photoreceptors (rods and ...

An Optic Nerve Crush Injury Murine Model to Study Retinal Ganglion Cell Survival

Injury to the optic nerve can lead to axonal degeneration, followed by a gradual death of retinal ganglion cells (RGCs), which results in irreversible vision loss. Examples of such diseases in human include traumatic optic neuropathy and optic nerve degeneration in glaucoma. It is characterized by typical changes in the optic nerve head, progressive optic nerve degeneration, and loss of retinal ganglion cells, if uncontrolled, leading to vision loss and blindness.
The optic nerve crush (ONC) injury mouse model is an important experimental disease model for traumatic optic neuropathy, glaucoma, etc. In this model, the crush injury to the optic nerve leads to gradual retinal ganglion cells apoptosis. This disease model can be used to study the general processes and mechanisms of neuronal death and survival, which is essential for the development of therapeutic measures. In addition, pharmacological and molecular approaches can be used in this model to identify and test potential therapeutic reagents to treat different types of optic neuropathy.
Here, we provide a step by step demonstration of (I) Baseline retrograde labeling of retinal ganglion cells (RGCs) at day 1, (II) Optic nerve crush injury at day 4, (III) Harvest the retinae and analyze RGC survival at day 11, and (IV) Representative result.

This protocol shows how to retrogradely label retinal ganglion cells, and how to subsequently make an optic nerve crush injury in order to analyze retinal ganglion cell survival and apoptosis. It is an experimental disease model for different types of optic neuropathy, including glaucoma.

Injury to the optic nerve can lead to axonal degeneration, followed by a gradual death of retinal ganglion cells (RGCs), which results in irreversible ...

Detection of Neuritic Plaques in Alzheimer's Disease Mouse Model

Alzheimer's disease (AD) is the most common neurodegenerative disorder leading to dementia. Neuritic plaque formation is one of the pathological hallmarks of Alzheimer's disease. The central component of neuritic plaques is a small filamentous protein called amyloid &beta; protein (A&beta;)1, which is derived from sequential proteolytic cleavage of the beta-amyloid precursor protein (APP) by &beta;-secretase and &gamma;-secretase. The amyloid hypothesis entails that A&gamma;-containing plaques as the underlying toxic mechanism in AD pathology2. The postmortem analysis of the presence of neuritic plaque confirms the diagnosis of AD. To further our understanding of A&gamma; neurobiology in AD pathogenesis, various mouse strains expressing AD-related mutations in the human APP genes were generated. Depending on the severity of the disease, these mice will develop neuritic plaques at different ages. These mice serve as invaluable tools for studying the pathogenesis and drug development that could affect the APP processing pathway and neuritic plaque formation. In this protocol, we employ an immunohistochemical method for specific detection of neuritic plaques in AD model mice. We will specifically discuss the preparation from extracting the half brain, paraformaldehyde fixation, cryosectioning, and two methods to detect neurotic plaques in AD transgenic mice: immunohistochemical detection using the ABC and DAB method and fluorescent detection using thiofalvin S staining method.

One of the pathological characteristics of AD is the formation of Amyloid &#x03B2; protein positive neuritic plaques. In this protocol we describe two methods to detect neuritic plaques in transgenic AD model mice: immunohistochemical detection using the ABC and DAB method and fluorescent detection using thioflavin S staining method.

Alzheimer's disease (AD) is the most common neurodegenerative disorder leading to dementia. Neuritic plaque formation is one of the pathological hallmarks ...

Whole Mount Immunofluorescent Staining of the Neonatal Mouse Retina to Investigate Angiogenesis In vivo

Angiogenesis is the complex process of new blood vessel formation defined by the sprouting of new blood vessels from a pre-existing vessel network. Angiogenesis plays a key role not only in normal development of organs and tissues, but also in many diseases in which blood vessel formation is dysregulated, such as cancer, blindness and ischemic diseases. In adult life, blood vessels are generally quiescent so angiogenesis is an important target for novel drug development to try and regulate new vessel formation specifically in disease. In order to better understand angiogenesis and to develop appropriate strategies to regulate it, models are required that accurately reflect the different biological steps that are involved. The mouse neonatal retina provides an excellent model of angiogenesis because arteries, veins and capillaries develop to form a vascular plexus during the first week after birth. This model also has the advantage of having a two-dimensional (2D) structure making analysis straightforward compared with the complex 3D anatomy of other vascular networks. By analyzing the retinal vascular plexus at different times after birth, it is possible to observe the various stages of angiogenesis under the microscope. This article demonstrates a straightforward procedure for analyzing the vasculature of a mouse retina using fluorescent staining with isolectin and vascular specific antibodies.

Whole Mount Immunofluorescent Staining of the Neonatal Mouse Retina to Investigate Angiogenesis In vivo

The neonatal murine retina provides a well characterized physiological model of angiogenesis, which permits investigations of the roles of different genes or drugs that modulate angiogenesis in an in vivo context. Immunofluorescent staining to accurately visualize the vascular plexus is pivotal to the success of these types of studies.

Angiogenesis  is the complex process of new blood vessel formation defined by the sprouting  of new blood vessels from a pre-existing vessel network. ...

Isolation and Culture of Endothelial Cells from the Embryonic Forebrain

Embryonic brain endothelial cells can serve as an important tool in the study of angiogenesis and neurovascular development and interactions. The two vascular networks of the embryonic forebrain, pial and periventricular, are spatially distinctive and have different origins and growth patterns. Endothelial cells from the pial and periventricular vascular networks have unique gene expression profiles and functions. Here we present a step-by-step protocol for isolation, culture, and verification of pure populations of endothelial cells from the periventricular vascular network (PVECs) of the embryonic forebrain (telencephalon). In this approach, telencephalon devoid of pial membrane obtained from embryonic day 15 mice is minced, digested with collagenase/dispase, and dispersed mechanically into a single cell suspension. PVECs are purified from cell suspension using positive selection with anti-CD-31/PECAM-1 antibody conjugated to MicroBeads using a strong magnetic separation method. Purified cells are cultured on collagen 1&#160;coated culture dishes in endothelial cell culture medium until they become confluent and further subcultured. PVECs obtained with this protocol exhibit cobblestone and spindle shaped phenotypes, as visualized by phase-contrast light microscopy and fluorescence microscopy. Purity of PVEC cultures was established with endothelial cell markers. In our hands, this method reliably and consistently yields pure populations of PVECs. This protocol will benefit studies aimed at gaining mechanistic insights into forebrain angiogenesis, understanding PVEC interactions, and cross-talks with neuronal cell types and holds tremendous potential for therapeutic angiogenesis.

This video demonstrates an easy and reliable strategy for preparation of pure cultures of endothelial cells from the embryonic forebrain within 10-12 days and will be useful for research focused on many aspects of cerebral angiogenesis.

Embryonic brain endothelial cells can serve as an important tool in the study of angiogenesis and neurovascular development and interactions. The two ...

A Simple Behavioral Assay for Testing Visual Function in Xenopus laevis

Measurement of the visual function in the tadpoles of the frog, Xenopus laevis, allows screening for blindness in live animals. The optokinetic response is a vision-based, reflexive behavior that has been observed in all vertebrates tested. Tadpole eyes are small so the tail flip response was used as alternative measure, which requires a trained technician to record the subtle response. We developed an alternative behavior assay based on the fact that tadpoles prefer to swim on the white side of a tank when placed in a tank with both black and white sides. The assay presented here is an inexpensive, simple alternative that creates a response that is easily measured. The setup consists of a tripod, webcam and nested testing tanks, readily available in most Xenopus laboratories. This article includes a movie showing the behavior of tadpoles, before and after severing the optic nerve. In order to test the function of one eye, we also include representative results of a tadpole in which each eye underwent retinal axotomy on consecutive days. Future studies could develop an automated version of this assay for testing the vision of many tadpoles at once.

A Simple Behavioral Assay for Testing Visual Function in Xenopus laevis

Xenopus laevis tadpoles prefer swimming on the white side of a black/white tank. This behavior is guided by their vision. Based on this behavior, we present a simple assay to test the visual function of tadpoles.

Measurement of the visual function in the tadpoles of the frog, Xenopus laevis, allows screening for blindness in live animals. The optokinetic response ...

Telomerase Activity in the Various Regions of Mouse Brain: Non-Radioactive Telomerase Repeat Amplification Protocol (TRAP) Assay

Telomerase, a ribonucleoprotein, is responsible for maintaining the telomere length and therefore promoting genomic integrity, proliferation, and lifespan. In addition, telomerase protects the mitochondria from oxidative stress and confers resistance to apoptosis, suggesting its possible importance for the surviving of non-mitotic, highly active cells such as neurons. We previously demonstrated the ability of novel telomerase activators to increase telomerase activity and expression in the various mouse brain regions and to protect motor neurons cells from oxidative stress. These results strengthen the notion that telomerase is involved in the protection of neurons from various lesions. To underline the role of telomerase in the brain, we here compare the activity of telomerase in male and female mouse brain and its dependence on age. TRAP assay is a standard method for detecting telomerase activity in various tissues or cell lines. Here we demonstrate the analysis of telomerase activity in three regions of the mouse brain by non-denaturing protein extraction using CHAPS lysis buffer followed by modification of the standard TRAP assay.
In this 2-step assay, endogenous telomerase elongates a specific telomerase substrate (TS primer) by adding TTAGGG 6 bp repeats (telomerase reaction). The telomerase reaction products are amplified by PCR reaction creating a DNA ladder of 6 bp increments. The analysis of the DNA ladder is made by 4.5% high resolution agarose gel electrophoresis followed by staining with highly sensitive nucleic acid stain.
Compared to the traditional TRAP assay that utilize 32P labeled radioactive dCTP&#39;s for DNA detection and polyacrylamide gel electrophoresis for resolving the DNA ladder, this protocol offers a non-toxic time saving TRAP assay for evaluating telomerase activity in the mouse brain, demonstrating the ability to detect differences in telomerase activity in the various female and male mouse brain region.

Telomerase Activity in the Various Regions of Mouse Brain: Non-Radioactive Telomerase Repeat Amplification Protocol TRAP Assay

Telomerase is expressed in the neonatal brain and also in distinct regions of the adult brain. We present a non-toxic time saving TRAP assay for the analysis of telomerase activity in various regions of the mouse brain and detection of differences in telomerase activity between male and female mouse brains.

Telomerase, a ribonucleoprotein, is responsible for maintaining the telomere length and therefore promoting genomic integrity, proliferation, and ...

A Volumetric Method for Quantification of Cerebral Vasospasm in a Murine Model of Subarachnoid Hemorrhage

Subarachnoid hemorrhage (SAH) is a subtype of hemorrhagic stroke. Cerebral vasospasm that occurs in the aftermath of the bleeding is an important factor determining patient outcome and is therefore frequently taken as a study endpoint. However, in small animal studies on SAH, quantification of cerebral vasospasm is a major challenge. Here, an ex vivo method is presented that allows quantification of volumes of entire vessel segments, which can be used as an objective measure to quantify cerebral vasospasm. In a first step, endovascular casting of the cerebral vasculature is performed using a radiopaque casting agent. Then, cross-sectional imaging data are acquired by micro computed tomography. The final step involves 3-dimensional reconstruction of the virtual vascular tree, followed by an algorithm to calculate center lines and volumes of the selected vessel segments. The method resulted in a highly accurate virtual reconstruction of the cerebrovascular tree shown by a diameter-based comparison of anatomical samples with their virtual reconstructions. Compared with vessel diameters alone, the vessel volumes highlight the differences between vasospastic and non-vasospastic vessels shown in a series of SAH and sham-operated mice.

The goal of this article is to present a method that allows a 3-dimensional reconstruction of the cerebrovascular tree in mice after micro computed tomography and determination of volumes of entire vessel segments that can be used to quantify cerebral vasospasm in murine models of subarachnoid hemorrhage.

Subarachnoid hemorrhage (SAH) is a subtype of hemorrhagic stroke. Cerebral vasospasm that occurs in the aftermath of the bleeding is an important factor ...