The authors thank Christiane Pahrmann for her technical assistance.
D.W. was supported by the Max Kade Foundation. T.D. received grants from the Else Kro&#776;ner Fondation (2012_EKES.04) and the Deutsche Forschungsgemeinschaft (DE2133/2-1_. S. S. received research grants from the Deutsche Forschungsgemeinschaft (DFG; SCHR992/3- 1, SCHR992/4-1).

Animals received humane care in compliance with the Guide for the Principles of Laboratory Animals, prepared by the Institute of Laboratory Animal Resources, and published by the National Institutes of Health. All animal protocols were approved by the responsible local authority (&#39;&#39;Amt f&#252;r Gesundheit und Verbraucherschutz, Hansestadt (Office for Health and Consumer Protection) Hamburg&#39;&#39;).
1. Catheter Preparation
NOTE: Refer to the Table of...

<ol>
	<li>Kochanek, K. D., Xu, J., Murphy, S. L., Minino, A. M., Kung, H. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Deaths:+final+data+for+2009.">Deaths: final data for 2009.</a> Natl Vital Stat Rep. 60 (3), 1-116 (2011).</li><li>Austin, G. E., Ratliff, N. B., Hollman, J., Tabei, S., Phillips, D. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intimal+proliferation+of+smooth+muscle+cells+as+an+explanation+for+recurrent+coronary+artery+stenosis+after+percutaneous+transluminal+coronary+angioplasty.">Intimal proliferation of smooth muscle cells as an explanation for recurrent coronary artery stenosis after percutaneous transluminal coronary angioplasty.</a> J Am Coll Cardiol. 6 (2), 369-375 (1985).</li><li>Greenwald, S. E., Berry, C. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improving+vascular+grafts:+the+importance+of+mechanical+and+haemodynamic+properties.">Improving vascular grafts: the importance of mechanical and haemodynamic properties.</a> J Pathol. 190 (3), 292-299 (2000).</li><li>Majesky, M. W., Schwartz, S. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Smooth+muscle+diversity+in+arterial+wound+repair.">Smooth muscle diversity in arterial wound repair.</a> Toxicol Pathol. 18 (4 Pt 1), 554-559 (1990).</li><li>Owens, G. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+differentiation+of+vascular+smooth+muscle+cells.">Regulation of differentiation of vascular smooth muscle cells.</a> Physiol Rev. 75 (3), 487-517 (1995).</li><li>Owens, G. K., Kumar, M. S., Wamhoff, B. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+regulation+of+vascular+smooth+muscle+cell+differentiation+in+development+and+disease.">Molecular regulation of vascular smooth muscle cell differentiation in development and disease.</a> Physiol Rev. 84 (3), 767-801 (2004).</li><li>Kleemann, R., Zadelaar, S., Kooistra, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cytokines+and+atherosclerosis:+a+comprehensive+review+of+studies+in+mice.">Cytokines and atherosclerosis: a comprehensive review of studies in mice.</a> Cardiovasc Res. 79 (3), 360-376 (2008).</li><li>Karas, S. P., 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=Coronary+intimal+proliferation+after+balloon+injury+and+stenting+in+swine:+an+animal+model+of+restenosis.">Coronary intimal proliferation after balloon injury and stenting in swine: an animal model of restenosis.</a> J Am Coll Cardiol. 20 (2), 467-474 (1992).</li><li>Ip, J. 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=The+role+of+platelets,+thrombin+and+hyperplasia+in+restenosis+after+coronary+angioplasty.">The role of platelets, thrombin and hyperplasia in restenosis after coronary angioplasty.</a> J Am Coll Cardiol. 17 (6 Suppl B), 77B-88B (1991).</li><li>Mason, R. G., Read, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Some+species+differences+in+fibrinolysis+and+blood+coagulation.">Some species differences in fibrinolysis and blood coagulation.</a> J Biomed Mater Res. 5 (1), 121-128 (1971).</li><li>Lafont, A., Faxon, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Why+do+animal+models+of+post-angioplasty+restenosis+sometimes+poorly+predict+the+outcome+of+clinical+trials?.">Why do animal models of post-angioplasty restenosis sometimes poorly predict the outcome of clinical trials?.</a> Cardiovasc Res. 39 (1), 50-59 (1998).</li><li>Matter, C. 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=Increased+balloon-induced+inflammation,+proliferation,+and+neointima+formation+in+apolipoprotein+E+(ApoE)+knockout+mice.">Increased balloon-induced inflammation, proliferation, and neointima formation in apolipoprotein E (ApoE) knockout mice.</a> Stroke. 37 (10), 2625-2632 (2006).</li><li>Lindner, V., Fingerle, J., Reidy, 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=Mouse+model+of+arterial+injury.">Mouse model of arterial injury.</a> Circ Res. 73 (5), 792-796 (1993).</li><li>Simon, D. I., 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=Decreased+neointimal+formation+in+Mac-1(-/-)+mice+reveals+a+role+for+inflammation+in+vascular+repair+after+angioplasty.">Decreased neointimal formation in Mac-1(-/-) mice reveals a role for inflammation in vascular repair after angioplasty.</a> J Clin Invest. 105 (3), 293-300 (2000).</li><li>Sata, 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=A+mouse+model+of+vascular+injury+that+induces+rapid+onset+of+medial+cell+apoptosis+followed+by+reproducible+neointimal+hyperplasia.">A mouse model of vascular injury that induces rapid onset of medial cell apoptosis followed by reproducible neointimal hyperplasia.</a> J Mol Cell Cardiol. 32 (11), 2097-2104 (2000).</li><li>Moroi, 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=Interaction+of+genetic+deficiency+of+endothelial+nitric+oxide,+gender,+and+pregnancy+in+vascular+response+to+injury+in+mice.">Interaction of genetic deficiency of endothelial nitric oxide, gender, and pregnancy in vascular response to injury in mice.</a> J Clin Invest. 101 (6), 1225-1232 (1998).</li><li>Painter, T. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Myointimal+hyperplasia:+pathogenesis+and+implications.+2.+Animal+injury+models+and+mechanical+factors.">Myointimal hyperplasia: pathogenesis and implications. 2. Animal injury models and mechanical factors.</a> Artif Organs. 15 (2), 103-118 (1991).</li><li>Stubbendorff, 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=Inducing+myointimal+hyperplasia+versus+atherosclerosis+in+mice:+an+introduction+of+two+valid+models.">Inducing myointimal hyperplasia versus atherosclerosis in mice: an introduction of two valid models.</a> J Vis Exp. (87), e51459 (2014).</li><li>Deuse, T., 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=Dichloroacetate+prevents+restenosis+in+preclinical+animal+models+of+vessel+injury.">Dichloroacetate prevents restenosis in preclinical animal models of vessel injury.</a> Nature. 509 (7502), 641-644 (2014).</li></ol>

This article demonstrates a murine model to study the development of myointimal hyperplasia and allows the exploration of the underlying pathological processes and the testing of new drugs or therapeutic options.
The most critical step in this protocol is the denudation of the aorta. Special care should be paid during this step as excessive denudation will lead to aneurysm formation and model failure. On the other hand, if denudation is performed insufficiently, too little myointima will devel...

Arterial stenosis in coronary and peripheral arteries has a large effect on the morbidity and mortality of patients1. One underlying pathological mechanism is myointima hyperplasia (MH), which is characterized by increased proliferation, migration, and synthesis of extracellular matrix proteins from vascular smooth muscle cells (SMC)2. SMC are located in the media layer of the vessel and migrate upon stimulation to the surface of the lumen. Stimulatory signals include growth factors, cytokines, cell-cell contact, lipids, extracellular matrix components, and mechanical shear and stretch forces3,4,5,6. Injuries of the vessel wall, pathological or iatrogenic, cause endothelial cell and smooth muscle cell damage and stimulate inflammatory reactions, and thus lead to MH7.
Different animal models are currently available to study arterial injury and myointima hyperplasia. Large animals like pigs or dogs have the advantage of sharing a similar artery and coronary anatomy with humans and are especially suitable for studies investigating angioplasty techniques, procedure, and devices8. However, pig models have the drawback of higher thrombogenicity9,10, while dogs only have a mild response to vessel injury11. In addition, all large animal models require special housing, equipment, and staff, which are connected with high costs and are not always available at an institution. Small animal models include rats and mice. Compared to rats, mice have the advantages of lower cost and the existence of a variety of knock out models. The model described in this video can be combined with ApoE-/- mice fed with a western diet to closely mimic the clinical setting of angioplasty in atherosclerotic vessels12. Previous models induced vascular injury via wire injury13, fluid desiccation14, spring15, or cuff injury16. Since the nature of the injury will greatly impact the development and constitution of MH, using a balloon catheter to induce vessel injury is the best way to mimic the clinical setting.
In this article we describe a novel method to induce MH with a balloon catheter in mice. The use of a balloon catheter (1.2 mm x 6 mm) with a RX-Port (Figure 1A) allows the scraping of the intimal layer and, at the same time, the induction of an overdistension of the vessel. Both of these factors are important triggers for the development of MH. The observation time for this model is 28 days17.

<table>
	<tbody>
		<tr>
			<td>10-0 Ethilon suture</td>
			<td>Ethicon</td>
			<td>2814G</td>
			<td></td>
		</tr>
		<tr>
			<td>3 mL Syringe</td>
			<td>BD Medical</td>
			<td>309658</td>
			<td></td>
		</tr>
		<tr>
			<td>37% HCl</td>
			<td>Sigma-Aldrich</td>
			<td>H1758</td>
			<td></td>
		</tr>
		<tr>
			<td>5-0 prolene suture</td>
			<td>Ethicon</td>
			<td>EH7229H</td>
			<td></td>
		</tr>
		<tr>
			<td>6-0 prolene suture</td>
			<td>Ethicon</td>
			<td>8706H</td>
			<td></td>
		</tr>
		<tr>
			<td>Acid Fuchsin</td>
			<td>Sigma-Aldrich</td>
			<td>F8129-25G</td>
			<td>Trichrome staining</td>
		</tr>
		<tr>
			<td>Antigen retrieval solution</td>
			<td>Dako</td>
			<td>S1699</td>
			<td></td>
		</tr>
		<tr>
			<td>Azophloxin</td>
			<td>Waldeck</td>
			<td>1B-103</td>
			<td>Trichrome staining</td>
		</tr>
		<tr>
			<td>Bepanthen Eye and Nose ointment</td>
			<td>Bayer</td>
			<td>1578675</td>
			<td>Eye ointment</td>
		</tr>
		<tr>
			<td>Betadine Solution</td>
			<td>Betadine Purdue Pharma</td>
			<td>NDC:67618-152</td>
			<td></td>
		</tr>
		<tr>
			<td>C57BL/6J</td>
			<td>Charles River</td>
			<td>Stock number 000664</td>
			<td></td>
		</tr>
		<tr>
			<td>Clamp applicator</td>
			<td>Fine Science Tools</td>
			<td>18056-14</td>
			<td></td>
		</tr>
		<tr>
			<td>Collagen 3</td>
			<td>abcam</td>
			<td>ab7778</td>
			<td>Antibody</td>
		</tr>
		<tr>
			<td>DAPI</td>
			<td>Thermo Fischer</td>
			<td>D1306</td>
			<td></td>
		</tr>
		<tr>
			<td>Donkey anti-Goat IgG AF555</td>
			<td>Invitrogen</td>
			<td>A21432</td>
			<td>Secondary antibody</td>
		</tr>
		<tr>
			<td>Donkey anti-Rabbit IgG AF488</td>
			<td>Invitrogen</td>
			<td>A21206</td>
			<td>Secondary antibody</td>
		</tr>
		<tr>
			<td>Donkey anti-Rabbit IgG AF488</td>
			<td>Invitrogen</td>
			<td>A11055</td>
			<td>Secondary antibody</td>
		</tr>
		<tr>
			<td>Donkey anti-Rabbit IgG AF555</td>
			<td>Invitrogen</td>
			<td>A31572</td>
			<td>Secondary antibody</td>
		</tr>
		<tr>
			<td>Ethanol 70%</td>
			<td>Th. Geyer</td>
			<td>2270</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol 96%</td>
			<td>Th. Geyer</td>
			<td>2295</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol absolute</td>
			<td>Th. Geyer</td>
			<td>2246</td>
			<td></td>
		</tr>
		<tr>
			<td>FAP</td>
			<td>abcam</td>
			<td>ab28246</td>
			<td>Antibody</td>
		</tr>
		<tr>
			<td>Forceps fine</td>
			<td>Fine Science Tools</td>
			<td>11251-20</td>
			<td></td>
		</tr>
		<tr>
			<td>Forceps standard</td>
			<td>Fine Science Tools</td>
			<td>11023-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Glacial Acetic Acid</td>
			<td>Sigma-Aldrich</td>
			<td>537020</td>
			<td></td>
		</tr>
		<tr>
			<td>Hair clipper</td>
			<td>WAHL</td>
			<td>8786-451A ARCO SE</td>
			<td></td>
		</tr>
		<tr>
			<td>Heparin</td>
			<td>Rotexmedica</td>
			<td>PZN 3862340</td>
			<td>25.000 I.E./mL</td>
		</tr>
		<tr>
			<td>High temperature cautery kit</td>
			<td>Bovie</td>
			<td>18010-00</td>
			<td></td>
		</tr>
		<tr>
			<td>Image-iT FX Signal Enhancer</td>
			<td>Invitrogen</td>
			<td>I36933</td>
			<td>Blocking solution</td>
		</tr>
		<tr>
			<td>Light Green SF</td>
			<td>Waldeck</td>
			<td>1B-211</td>
			<td>Trichrome staining</td>
		</tr>
		<tr>
			<td>Microsurgical clamp</td>
			<td>Fine Science Tools</td>
			<td>18055-04</td>
			<td>Micro-Serrefine - 4mm</td>
		</tr>
		<tr>
			<td>MINI TREK Coronary Dilatation Catheter 1.20 mm x 6 mm / Rapid-Exchange</td>
			<td>Abbott</td>
			<td>1012268-06U</td>
			<td></td>
		</tr>
		<tr>
			<td>Molybdatophosphoric acid hydrate</td>
			<td>Merck</td>
			<td>1.00532.0100</td>
			<td>Trichrome staining</td>
		</tr>
		<tr>
			<td>NaCl 0,9%</td>
			<td>B.Braun</td>
			<td>PZN 06063042 Art. Nr.: 3570160</td>
			<td></td>
		</tr>
		<tr>
			<td>Needle holder</td>
			<td>Fine Science Tools</td>
			<td>12075-14</td>
			<td></td>
		</tr>
		<tr>
			<td>Novaminsulfon</td>
			<td>Ratiopharm</td>
			<td>PZN 03530402</td>
			<td>Metamizole</td>
		</tr>
		<tr>
			<td>Orange G</td>
			<td>Waldeck</td>
			<td>1B-221</td>
			<td>Trichrome staining</td>
		</tr>
		<tr>
			<td>Paraffin</td>
			<td>Leica biosystems</td>
			<td>REF 39602004</td>
			<td></td>
		</tr>
		<tr>
			<td>PBS pH 7,4</td>
			<td>Gibco</td>
			<td>10010023</td>
			<td></td>
		</tr>
		<tr>
			<td>PFA 4%</td>
			<td>Electron Microscopy Sciences</td>
			<td>#157135S</td>
			<td></td>
		</tr>
		<tr>
			<td>Ponceau S solution</td>
			<td>Serva Electrophoresis</td>
			<td>33427</td>
			<td>Trichrome staining</td>
		</tr>
		<tr>
			<td>Primary antibody diluent</td>
			<td>Dako</td>
			<td>S3022</td>
			<td></td>
		</tr>
		<tr>
			<td>Prolong Gold Mounting solution</td>
			<td>Thermo Fischer</td>
			<td>P36930</td>
			<td>Mounting solution for immunofluorescence stained slides</td>
		</tr>
		<tr>
			<td>Replaceable Fine Tip</td>
			<td>Bovie</td>
			<td>H101</td>
			<td></td>
		</tr>
		<tr>
			<td>Resorcin-Fuchsin Weigert</td>
			<td>Waldeck</td>
			<td>2E-30</td>
			<td>Trichrome staining</td>
		</tr>
		<tr>
			<td>Rimadyl</td>
			<td>Pfizer</td>
			<td>400684.00.00</td>
			<td>Carprofen</td>
		</tr>
		<tr>
			<td>Scissors</td>
			<td>Fine Science Tools</td>
			<td>14028-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Scissors Vannas-style</td>
			<td>Fine Science Tools</td>
			<td>15000-03</td>
			<td></td>
		</tr>
		<tr>
			<td>Secondary antibody diluent</td>
			<td>Dako</td>
			<td>S0809</td>
			<td></td>
		</tr>
		<tr>
			<td>Fast acting Adhesive MINIS 3x1g</td>
			<td>UHU</td>
			<td>45370</td>
			<td>Cyanoacrylate</td>
		</tr>
		<tr>
			<td>Slide Rack</td>
			<td>Ted Pella</td>
			<td>21057</td>
			<td></td>
		</tr>
		<tr>
			<td>SM22</td>
			<td>abcam</td>
			<td>ab10135</td>
			<td>Antibody</td>
		</tr>
		<tr>
			<td>SMA</td>
			<td>abcam</td>
			<td>ab21027</td>
			<td>Antibody</td>
		</tr>
		<tr>
			<td>Staining dish</td>
			<td>Ted Pella</td>
			<td>21075</td>
			<td></td>
		</tr>
		<tr>
			<td>Surgical microscope</td>
			<td>Leica</td>
			<td>M651</td>
			<td></td>
		</tr>
		<tr>
			<td>Tabotamp fibrillar</td>
			<td>Ethicon</td>
			<td>431962</td>
			<td>Absorbable hemostat</td>
		</tr>
		<tr>
			<td>Transpore Surgical Tape</td>
			<td>3M</td>
			<td>1527-1</td>
			<td></td>
		</tr>
		<tr>
			<td>U-100 Insulin syringe</td>
			<td>BD Medical</td>
			<td>324825</td>
			<td></td>
		</tr>
		<tr>
			<td>Vessel Dilator</td>
			<td>Fine Science Tools</td>
			<td>18603-14</td>
			<td></td>
		</tr>
		<tr>
			<td>Vitro-Clud</td>
			<td>Langenbrinck</td>
			<td>04-0001</td>
			<td></td>
		</tr>
		<tr>
			<td>Weigerts iron hematoxylin Kit</td>
			<td>Merck</td>
			<td>1.15973.0002</td>
			<td>Trichrome staining</td>
		</tr>
		<tr>
			<td>Xylene</td>
			<td>Th. Geyer</td>
			<td>3410</td>
			<td></td>
		</tr>
	</tbody>
</table>

balloon-based injury to induce myointimal hyperplasia in the mouse abdominal aorta

The use of animal models is essential for a better understanding of MH, one major cause for arterial stenosis.In this article, we demonstrate a murine balloon denudation model, which is comparable with established vessel injury models in large animals. The aorta denudation model with balloon catheters mimics the clinical setting and leads to comparable pathobiological and physiological changes. Briefly, after performing a horizontal incision in the aorta abdominalis, a balloon catheter will be inserted into the vessel, inflated, and introduced retrogradely. Inflation of the balloon will lead to intima injury and overdistension of the vessel. After removing the catheter, the aortic incision will be closed with single stiches. The model shown in this article is reproducible, easy to perform, and can be established quickly and reliably. It is especially suitable for evaluating expensive experimental therapeutic agents, which can be applied in an economical fashion. By using different knockout-mouse strains, the impact of different genes on MH development can be assessed.

Balloon denudation is a suitable model to study the development of MH in mice. Animals recover well from the surgery and show an excellent physical condition post-operation. We established this model in 50 mice with less than 3% death rate due to the surgical procedure. Figures 1B-C show the key surgical steps. After a skin incision along the linea alba, identify the aorta abdominalis. Place microsurgical clamps (<strong cla...

Watch this Scientific Journal Video about Balloon-based Injury to Induce Myointimal Hyperplasia in the Mouse Abdominal Aorta at JoVE.com

Balloon-based Injury to Induce Myointimal Hyperplasia in the Mouse Abdominal Aorta

This article demonstrates a murine model to study the development of myointimal hyperplasia (MH) after aortic balloon injury.

The use of animal models is essential for a better understanding of MH, one major cause for arterial stenosis.In this article, we demonstrate a murine ...

The overall goal of this mouse based model system is to study the development of myointimal hyperplasia after aortic balloon injury. This model system can help answer key questions about myointimal hyperplasia such as what factors contribute to its development. By studying the development of myointimal hyperplasia in transgenic mice we hope to gain a better understanding of the pathomechanism of the disease.Another advantage of this animal model, is that the disease progresses quickly. In just weeks, we're studied in mice. First, prepare the required catheter.Remove it from the holder and pull the guide wire out through the lumen through the distal port. Next put in a drop of cyanoacrylate on the distal end of the catheter and feed the guide wire through the RX port, then through the lumen and out the distal port. Next pull the guide wire back slightly to leave about five millimieters sticking out and let the adhesive dry.Later fill a three milliliter syringe with 1.5 milliliters of 0.9%saline and connect it to the ballon inflation port of the catheter. Then push the plunger to test the balloon inflation. Leave about 0.6 milliliters of saline in the syringe.Next, prepare the mouse for surgery. Anesthetize it in an isoflurane chamber and later, during surgery, deliver isoflurane via a nose cone. Before proceeding, confirm a sufficient depth of anesthesia by pinching the hind feet and tail to verify an absence of reflexes.Then remove the abdominal hair using a hair trimmer and fix the position of the hind legs using tape. Lastly, disinfect the abdominal area using three alternating scrubs of povidone iodine followed by 80%ethanol. Begin with dissecting open the skin and muscle layers along the linea alba to expose the abdominal organs.Then move aside the intestines, wrap them in a saline soaked gauze to keep them moist. Now using two fine forceps to remove the fatty tissue above the abdominal aorta. Then from an insulin syringe, inject about 12 units of heparin sulfate in to the IVC and wait three minutes for systemic distribution.Next use forceps to dissect the infrarenal aorta down to the bifurcation and to reveal the outgoing branches. Then using cauterization, ligate the side vessels along the infrarenal aorta within the area that will be clamped. Then, stop the blood flow by clamping the vessel directly beneath the renal arteries and clamping at a distal position just above the aortic bifurcation.Now perform a small horizontal incision along the vessel at the midpoint between the clamps. The incision should be about 1/3 the circumference of the vessel. Then, using an insulin syringe, flush the aorta with heparin solution as before.Next place 10-0 sutures with single knots on each side of the incision. To proceed, dilate the aorta. Place a vessel dilator in to the incision and spread the vessel slightly.Do this two or three times. Then prepare the balloon catheter by wetting it with saline. Then insert the balloon catheter deflated in to the aorta and advance it towards the proximal clamp.Carefully open the proximal clamp and inflate the balloon to prevent blood leakage by injecting about 0.6 milliliters of saline. Next, advance the catheter retrograde about two centimeters. Pull the catheter back while deflating the balloon slightly.When the catheter reaches the incision of the aorta, reattach the proximal clamp. Then, deflate the balloon completely and remove it. Now rinse the aorta with heparin solution.Then proceed by closing the aortic incision using interrupted 10-0 sutures on each lateral side. Followed by one or two stitches on the ventral side. Next open the distal clamp, check for bleeding and place additional sutures as needed.Once there's no bleeding, carefully open the proximal clamp. Use swabs on the sutures for support and to slow bleeding. Then place absorbable hemostats on the sutures to sustain them.With both clamps opened, an aortic pulse should be visible distally from the incision. Now place the intestines back in to the abdomen and rinse the abdominal cavity with saline warmed to 37 degrees Celsius. Next close the abdominal muscle layer using 6-0 running sutures.And then close the skin with 5-0 running sutures. Next immediately inject an analgesic subcutaneously before the animal wakes up. Now monitor the mouse until it has gained consciousness and can maintain sternal recumbency.Once conscious, house the animal alone until it has completely recovered. Provide Metamizole to the drinking water for three days. Be sure to check on the mouse every day to ensure a good recovery.Balloon denudation is a suitable method to study the development of myointimal hyperplasia in mice. Animals recovered well from the surgery and were in excellent physical condition. Less than 3%died in over 50 surgeries.Myointimal hyperplasia developed progressively in the graft. Histological staining with Masson's trichrome showed the myointima formation inside the internal elastic lamina. The myointimal lesions consisted mainly of cellular components positive for SM22 indicating smooth muscle cells and ECM cells like myofibroblasts also shown in red.After watching this video you should have a good understanding how to perform the balloon injuries in mice. Once mastered, this technique can be done in 20 minutes if it's performed properly.

balloon-based-injury-to-induce-myointimal-hyperplasia-mouse-abdominal

Research

JoVE Journal

Medicine

9.4K visualizações.  University Heart Center. The overall goal of this mouse based model system is to study the development of myointimal hyperplasia after aortic balloon injury. This model system can help answer key questions about myointimal hyperplasia such as what factors contribute to its development. By studying the development of myointimal hyperplasia in transgenic mice we hope to gain a better understanding of the pathomechanism of the disease.Another advantage of this animal model, is that the disease progresses quickly....