The authors thank Christiane Pahrmann for technical assistance. S.S. received funding from the Deutsche Forschungsgemeinschaft (DFG) (SCHR992/3-2 and SCHR992/4-2).

All animal work should be carried out according to relevant animal care guidelines. Obtain institutional approval for animal work prior to beginning protocol.
1. Myointimal Hyperplasia Model (A)
For the intimal hyperplasia model, purchase C57BL/6J (Stock number 000664, C57BL/6J) mice at the age of 8 weeks weighing approximately 25 g. House mice for these experiments under conventional conditions; feed mice standard mouse chow and provide water ad libitum.
<ol>
	<li>Mouse preparation: Introduce the mouse to an anesthetic state with isoflurane (2%) utilizing an induction chamber.
	<ol>
		<li>Remove the abdominal hair using a hair trimmer, lay the mouse on its back and cover its nose and mouth with the facemask to assure the anesthesia.</li>
		<li>With Provo-Iodine, disinfect the abdominal area universally, followed by 80% ethanol, in two cycles.</li>
		<li>Assure the absence of reflexes by pinching the hind limb to monitor the sufficient depth of anesthesia.</li>
		<li>Separate the skin and muscle along the linea alba in two steps to expose&#160;the abdominal organs.</li>
		<li>Lay the intestines in a saline moisturized glove. Wrap the glove around the intestines to keep them moist.</li>
		<li>Attentively clear away the fatty tissue sheeting the abdominal aorta. Expose the infrarenal aorta down to its bifurcation, taking care not to injure any branch vessels.</li>
		<li>First, place a microsurgical clamp on the proximal, infrarenal aorta to shut down the blood flow. Now, apply a second distal clamp next to the aortic bifurcation.</li>
		<li>When the blood flow is interrupted, make a small incision into the aorta close to the proximal clamp.</li>
		<li>Insert the balloon-tipped catheter, which has been moisturized with 0.9% saline, and advance towards the distal clamp of the aorta.</li>
		<li>For endothelial injury, denude the aorta by inflating the balloon carefully and slowly pulling the catheter into the direction of the proximal clamp.</li>
		<li>Repeat the denudation maneuver twice.</li>
		<li>Remove the catheter and close the aortic incision using 10-0 prolene running sutures.</li>
		<li>Carefully open the distal clamp. In case of bleeding at the aortotomy site, close the clamp again, locate the bleeding and place additional interrupted stitches, as necessary.</li>
		<li>If no bleeding can be observed, slowly open the proximal clamp.</li>
		<li>An aortic pulse should be visible distally from the incision. Now the intestines can be arranged back in situ.</li>
		<li>Rinse the abdominal cavity utilizing pre-warmed sterile saline.</li>
		<li>Close the abdominal wall beginning with the muscle layer using 6-0 prolene running sutures.</li>
		<li>Next adapt the skin under the use of 5-0 prolene performing running sutures.</li>
		<li>During the time the mouse is still anesthetized, apply 4-5 mg/kg Carprofen via a subcutaneous injection.</li>
		<li>Add Metamizol to the drinking water (50 mg Metamizol per 100 ml) for pain control and continue for 3 days post surgery. Monitor animal throughout recovery. 
		Note: The observation period for this model is 28 days.</li>
	</ol>
	</li>
</ol>
2. Atherosclerosis Model (B)
For the atherosclerosis model, purchase apolipoprotein E-deficient (ApoE -/-) mice (Stock number 002052, B6.129P2-Apoetm1Unc/J) at an age of&#160;4 weeks, and then fed for 4-6 months. House mice for these experiments under conventional conditions; feed mice high lipid western diet upon arrival (Harlan Laboratories TD.88137) and provide water ad libitum for a duration of 4 to 6 months.
<ol>
	<li>Mouse preparation:
	<ol>
		<li>Feed the ApoE -/- mice with western diet beginning at 4 weeks&#160;of age. Dietary manipulation should begin directly upon arrival.</li>
		<li>Maintain western diet throughout duration of experiment.</li>
	</ol>
	</li>
</ol>
3. Analysis
<ol>
	<li>Myointimal hyperplasia model (A) 
	The region of interest in this model is the &#8220;lesion area&#8221;. Options for analysis include luminal obliteration, I/M ratio (intima/media ratio), maximal myointima thickness, myointimal area, Trichrome staining for fibrosis, and H&#38;E staining for mononuclear cells (as illustrated in Figures 1A-1C). According to the scientific question numerous other stainings like Picrosirius red for collagen, immunohistochemistry, and confocal methods can be applied.</li>
	<li>Atherosclerosis model (B) The regions of interest in this model are the aortic valve, aortic arch as well as the descending aorta. Options for analysis: Sudan red staining for lipids and trichrome staining of aortic valve, aortic arch and descending aorta (as illustrated in Figure 1D). 
	This model also yields a variety of other staining options like for example Oil Red O for neutral lipids, Picrosirius red, immunohistochemistry, and confocal methods.
	<ol>
		<li>Sudan red staining: Perform the Sudan red staining on freshly harvested aortic tissue.
		<ol>
			<li>Remove the diet 6h before harvesting.</li>
			<li>Introduce the mouse to an anesthetic state with isoflurane (2%) utilizing an induction chamber. Assure the absence of reflexes by pinching the hind limb to monitor the sufficient depth of anesthesia.</li>
			<li>Open the chest; cut off the apex of the heart and perfuse via the left ventricle, first with saline (3 ml), followed by 4% PFA (3 ml) through the aortic root to fix the aorta.</li>
			<li>Free the aorta from the root to its bifurcation. Try to remove fatty tissue as much as possible.</li>
			<li>Cut off the heart and the aortic root, and store them in 4% PFA for histology.</li>
			<li>For histology the aortic root has to carefully be placed in the paraffin block in an upright position to allow the cutting of the aortic root generating slides that display all 3 valvular leaflets.</li>
			<li>Cut one end of the aortic tree and fix it onto the silicone layer with fine pins. Open the aorta longitudinally and fix the aortic tissue.</li>
			<li>Rinse the tissue with 50% ethanol. Immerse the tissue with Sudan III staining solution for about 15 min.</li>
			<li>Rinse lightly with 50% ethanol to remove the excess Sudan III. (Note: 50% ethanol may wash the dye away.) Rinse with dH2O, and take photos for further analysis.</li>
		</ol>
		</li>
	</ol>
	</li>
</ol>

<ol>
	<li>Manuel, D. G., Leung, M., Nguyen, K., Tanuseputro, P., Johansen, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Burden+of+cardiovascular+disease+in+Canada.">Burden of cardiovascular disease in Canada.</a> Can J Cardiol. 19, 997-1004 (2003).</li><li>ER, O. B., Ma, X., Simard, T., Pourdjabbar, A., Hibbert, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pathogenesis+of+neointima+formation+following+vascular+injury.">Pathogenesis of neointima formation following vascular injury.</a> Cardiovasc Hematol Disord Drug Targets. 11, 30-39 (2011).</li><li>Ross, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+pathogenesis+of+atherosclerosis:+a+perspective+for+the+1990s.">The pathogenesis of atherosclerosis: a perspective for the 1990s.</a> Nature. 362, 801-809 (1993).</li><li>Meng, X., Zhang, F., Valji, 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=Ultrasound+guidance+for+the+creation+of+a+small+animal+model+of+aortic+injury.">Ultrasound guidance for the creation of a small animal model of aortic injury.</a> J Vasc Interv Radiol. 22, 1193-1197 (2011).</li><li>Deuse, T., Koyanagi, T., Erben, R. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sustained+inhibition+of+epsilon+protein+kinase+C+inhibits+vascular+restenosis+after+balloon+injury+and+stenting.">Sustained inhibition of epsilon protein kinase C inhibits vascular restenosis after balloon injury and stenting.</a> Circulation. 122, 170-178 (2010).</li><li>Schrepfer, S., Deuse, T., Sultan, K. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inhibition+of+restenosis+development+after+mechanical+injury:+a+new+field+of+application+for+malononitrilamides.">Inhibition of restenosis development after mechanical injury: a new field of application for malononitrilamides.</a> Cardiology. 108, 128-137 (2007).</li><li>Tao, M., Mauro, C. R., Yu, 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=A+simplified+murine+intimal+hyperplasia+model+founded+on+a+focal+carotid+stenosis.">A simplified murine intimal hyperplasia model founded on a focal carotid stenosis.</a> Am J Pathol. 182, 277-287 (2013).</li><li>Kumar, A., Lindner, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Remodeling+with+neointima+formation+in+the+mouse+carotid+artery+after+cessation+of+blood+flow.">Remodeling with neointima formation in the mouse carotid artery after cessation of blood flow.</a> Arterioscler Thromb Vasc Biol. 17, 2238-2244 (1997).</li><li>Hua, X., Deuse, T., Michelakis, E. D., 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=Human+internal+mammary+artery+(IMA)+transplantation+and+stenting:+a+human+model+to+study+the+development+of+in-stent+restenosis.">Human internal mammary artery (IMA) transplantation and stenting: a human model to study the development of in-stent restenosis.</a> J Vis Exp. , 3663 (2012).</li><li>Daugherty, A., Whitman, S. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantification+of+atherosclerosis+in+mice.">Quantification of atherosclerosis in mice.</a> Methods Mol Biol. , (2003).</li><li>Nakashima, Y., Plump, A. S., Raines, E. W., Breslow, J. L., Ross, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ApoE-deficient+mice+develop+lesions+of+all+phases+of+atherosclerosis+throughout+the+arterial+tree.">ApoE-deficient mice develop lesions of all phases of atherosclerosis throughout the arterial tree.</a> Arterioscler Thromb. 14, 133-1340 (1994).</li><li>Zhang, Y., Li, L., You, J., Cao, J., Fu, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+7-difluoromethyl-5,+4'-dimethoxygenistein+on+aorta+atherosclerosis+in+hyperlipidemia+ApoE(-/-)+mice+induced+by+a+cholesterol-rich+diet.">Effect of 7-difluoromethyl-5, 4'-dimethoxygenistein on aorta atherosclerosis in hyperlipidemia ApoE(-/-) mice induced by a cholesterol-rich diet.</a> Drug Des Devel Ther. 7, 233-242 (2013).</li><li>Rudolph, T. K., Rudolph, V., Edreira, M. 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=Nitro-fatty+acids+reduce+atherosclerosis+in+apolipoprotein+E-deficient+mice.">Nitro-fatty acids reduce atherosclerosis in apolipoprotein E-deficient mice.</a> Arterioscler Thromb Vasc Biol. 30, 938-9345 (2010).</li><li>Rondelet, B., Kerbaul, F., Motte, S., 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=Bosentan+for+the+prevention+of+overcirculation-induced+experimental+pulmonary+arterial+hypertension.">Bosentan for the prevention of overcirculation-induced experimental pulmonary arterial hypertension.</a> Circulation. 107, 1329-1335 (2003).</li><li>Zeibig, S., Li, Z., Wagner, S., 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=Effect+of+the+oxLDL+binding+protein+Fc-CD68+on+plaque+extension+and+vulnerability+in+atherosclerosis.">Effect of the oxLDL binding protein Fc-CD68 on plaque extension and vulnerability in atherosclerosis.</a> Circ Res. 108, 695-703 (2011).</li><li>Painter, T. 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The authors have nothing to disclose.

Although both diseases result in similar symptoms in the patient, the underlying mechanisms of plaque development and therefore the treatment approaches are very different2. In different forms of arterial stenosis the clinical findings in the patients as well as the timeframe of plaque development depend on the underlying mechanism.
Depending on the clinical findings in the patient, different methods of sample analysis must be performed5,15. It is necessary to adapt the a...

In industrialized nations ischemic heart disease remains a leading cause of mortality1. The causes for coronary artery stenosis are manifold and include myointimal hyperplasia as well as atherosclerosis, with revascularization remaining the most common treatment strategy2. Research models that clearly distinguish between the mechanistic pathways of intimal hyperplasia and atherosclerosis are essential to investigate the pathobiological and pathophysiological processes in arterial plaque development. In this video two different mouse models used to study either the development of myointimal hyperplasia or atherosclerosis are introduced.
Myointimal hyperplasia is postulated to form via the &#8220;response-to-injury&#8221; paradigm originally described for atherosclerosis3. The mechanical disruption of the endothelial layer leads to an intense remodeling enhanced by paracrine effects. There are several different animal models commonly used to study myointimal hyperplasia. Some groups use metal devices in the ascending aorta of rats4. The aortic denudation model performed with a balloon catheter is also commonly used in laboratory rats5,6. The intimal hyperplasia model performed in laboratory mice7 implements ligation of the carotid artery and induces myointimal lesions8. In our lab, the abdominal aortic denudation model &#8211; to study the development of myointimal hyperplasia &#8211; as well as a humanized stent restenosis model9 are commonly used. This video emphasizes that choosing the proper experimental animal model is crucial for mechanistic or pathophysiologic studies of arterial stenosis.
Myointimal hyperplasia models must be distinguished from atherosclerosis models. For the latter, apolipoprotein E-deficient (ApoE -/-) mice in combination with western diet are commonly used to induce atherosclerotic lesions10,11,12,13. Examples for the induction of both of these types of myointimal disease in mice are shown here, along with different model-adapted options to analyze vessel stenosis14.

<table border="0" cellpadding="0" cellspacing="0" style="width:617px;" width="618">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="17">
			<td height="17" style="height:17px;width:156px;">Name</td>
			<td style="width:183px;">Company</td>
			<td style="width:139px;">Catalog number</td>
			<td style="width:140px;">Comments</td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;">Thyoglycollate Broth 3%</td>
			<td>Fluka</td>
			<td align="right">70157</td>
			<td>powder</td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;">PFA 4%</td>
			<td>Electron Microscopy Sciences</td>
			<td>#157135S</td>
			<td align="right">20%</td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;">Sudan III staining solution</td>
			<td>Sigma Aldrich</td>
			<td>S4131</td>
			<td>powder</td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;">mouse C57BL/6J</td>
			<td>Jackson Laboratories</td>
			<td>&#160;Stock # 0006664</td>
			<td></td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;">mouse ApoE-/-</td>
			<td>Jackson Laboratories</td>
			<td>&#160;Stock #002052</td>
			<td></td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;">Western Diet</td>
			<td>Harlan Laboratories</td>
			<td>TD.88137</td>
			<td></td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;">hair clipper</td>
			<td>WAHL</td>
			<td>8786-451A ARCO SE</td>
			<td></td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;">Forene</td>
			<td>Abbott</td>
			<td></td>
			<td>Isoflurane</td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;">microsurgical clamp</td>
			<td>Fine Science Tools</td>
			<td>18055-04</td>
			<td>Micro-Serrefine - 4mm</td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;">clamp applicator</td>
			<td>Fine Science Tools</td>
			<td>18056-14</td>
			<td></td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;">catheter</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;">10-0 prolene suture</td>
			<td>Ethicon</td>
			<td>788G</td>
			<td></td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;">6-0 prolene suture</td>
			<td>Ethicon</td>
			<td>8709H</td>
			<td></td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;">5-0 prolene suture</td>
			<td>Ethicon</td>
			<td>EH7229H</td>
			<td></td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;">Rimadyl</td>
			<td>Pfizer&#160;</td>
			<td></td>
			<td>Carprofen</td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;">Metacam 1.5mg/ml</td>
			<td>Boehringer Ingelheim</td>
			<td></td>
			<td>Metamizol</td>
		</tr>
	</tbody>
</table>

inducing myointimal hyperplasia versus atherosclerosis in mice: an introduction of two valid models

Various in vivo laboratory rodent models for the induction of artery stenosis have been established to mimic diseases that include arterial plaque formation and stenosis, as observed for example in ischemic heart disease. Two highly reproducible mouse models&#160;&#8211;&#160;both resulting in artery stenosis but each underlying a different pathway of development&#160;&#8211; are introduced here. The models represent the two most common causes of artery stenosis; namely one mouse model for each myointimal hyperplasia, and atherosclerosis are shown. To induce myointimal hyperplasia, a balloon catheter injury of the abdominal aorta is performed. For the development of atherosclerotic plaque, the ApoE -/- mouse model in combination with western fatty diet is used. Different model-adapted options for the measurement and evaluation of the results are named and described in this manuscript. The introduction and comparison of these two models provides information for scientists to choose the appropriate artery stenosis model in accordance to the scientific question asked.

Figure 1 shows different analysis options and the induced disease state for both models. For the intimal hyperplasia model, the analysis of representative cross sections in trichrome staining is shown. From these cross sections, results like I/M ratios, maximum plaque thickness, maximum intimal thickness in the lumen, luminal obliteration in percent, as well as plaque area can be measured and calculated.
To evaluate the outcome of the atherosclerosis model, all methods named a...

Watch this Scientific Journal Video about Inducing Myointimal Hyperplasia Versus Atherosclerosis in Mice: An Introduction of Two Valid Models at JoVE.com

Inducing Myointimal Hyperplasia Versus Atherosclerosis in Mice: An Introduction of Two Valid Models

This video shows two models of intimal plaque development in murine arteries and emphasizes the differences in myointimal hyperplasia and atherosclerosis.

Various in vivo laboratory rodent models for the induction of artery stenosis have been established to mimic diseases that include arterial plaque ...

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12.0K Views.  University Hospital Hamburg. This video shows two models of intimal plaque development in murine arteries and emphasizes the differences in myointimal hyperplasia and atherosclerosis.

Video: Inducing Myointimal Hyperplasia Versus Atherosclerosis in Mice: An Introduction of Two Valid Models

Implantation of a Carotid Cuff for Triggering Shear-stress Induced Atherosclerosis in Mice

It is widely accepted that alterations in vascular shear stress trigger the expression of inflammatory genes in endothelial cells and thereby induce atherosclerosis (reviewed in 1 and 2). The role of shear stress has been extensively studied in vitro investigating the influence of flow dynamics on cultured endothelial cells 1,3,4 and in vivo in larger animals and humans 1,5,6,7,8. However, highly reproducible small animal models allowing systematic investigation of the influence of shear stress on plaque development are rare. Recently, Nam et al. 9 introduced a mouse model in which the ligation of branches of the carotid artery creates a region of low and oscillatory flow. Although this model causes endothelial dysfunction and rapid formation of atherosclerotic lesions in hyperlipidemic mice, it cannot be excluded that the observed inflammatory response is, at least in part, a consequence of endothelial and/or vessel damage due to ligation.
In order to avoid such limitations, a shear stress modifying cuff has been developed based upon calculated fluid dynamics, whose cone shaped inner lumen was selected to create defined regions of low, high and oscillatory shear stress within the common carotid artery 10. By applying this model in Apolipoprotein E (ApoE) knockout mice fed a high cholesterol western type diet, vascular lesions develop upstream and downstream from the cuff. Their phenotype is correlated with the regional flow dynamics 11 as confirmed by in vivo Magnetic Resonance Imaging (MRI) 12: Low and laminar shear stress upstream of the cuff causes the formation of extensive plaques of a more vulnerable phenotype, whereas oscillatory shear stress downstream of the cuff induces stable atherosclerotic lesions 11. In those regions of high shear stress and high laminar flow within the cuff, typically no atherosclerotic plaques are observed.
 
In conclusion, the shear stress-modifying cuff procedure is a reliable surgical approach to produce phenotypically different atherosclerotic lesions in ApoE-deficient mice.

The constricting cuff presented in this article is designed to induce atherosclerosis in the murine common carotid artery. Due to the conical shape of its inner lumen the implanted cuff generates well-defined regions of low, high and oscillatory shear stress triggering the development of atherosclerotic lesions of different inflammatory phenotypes.

It is widely accepted that alterations in vascular shear stress trigger the expression of inflammatory genes in endothelial cells and thereby induce ...

Quantitative Analysis and Characterization of Atherosclerotic Lesions in the Murine Aortic Sinus

Atherosclerosis is a disease of the large arteries and a major underlying cause of myocardial infarction and stroke. Several different mouse models have been developed to facilitate the study of the molecular and cellular pathophysiology of this disease. In this manuscript we describe specific techniques for the quantification and characterization of atherosclerotic lesions in the murine aortic sinus and ascending aorta. The advantage of this procedure is that it provides an accurate measurement of the cross-sectional area and total volume of the lesion, which can be used to compare atherosclerotic progression across different treatment groups. This is possible through the use of the valve leaflets as an anatomical landmark, together with careful adjustment of the sectioning angle. We also describe basic staining methods that can be used to begin to characterize atherosclerotic progression. These can be further modified to investigate antigens of specific interest to the researcher. The described techniques are generally applicable to a wide variety of existing and newly created dietary and genetically-induced models of atherogenesis.

We describe procedures to quantify and characterize atherosclerotic lesions in mouse models using precision sectioning of the aortic sinus and ascending aorta combined with histochemical and immunohistochemical analysis.

Atherosclerosis is a disease of the large arteries and a major underlying cause of myocardial infarction and stroke. Several different mouse models have ...

Minimal Invasive Surgical Procedure of Inducing Myocardial Infarction in Mice

Myocardial infarction still remains the main cause of death in western countries, despite considerable progress in the stent development area in the last decades. For clarification of the underlying mechanisms and the development of new therapeutic strategies, the availability of valid animal models are mandatory. Since we need new insights into pathomechanisms of cardiovascular diseases under in vivo conditions to combat myocardial infarction, the validity of the animal model is a crucial aspect. However, protection of animals are highly relevant in this context. Therefore, we establish a minimally invasive and simple model of myocardial infarction in mice, which assures a high reproducibility and survival rate of animals. Thus, this models fulfils the requirements of the 3R principle (Replacement, Refinement and Reduction) for animal experiments and assure the scientific information needed for further developing of therapeutical strategies for cardiovascular diseases.

A highly reproducible model for myocardial infarction in mice with minimal invasive manipulations is described. The model can be easily performed, resulting in a high reproducibility and survival rate. Thus, the described model will reduce the number of required animals as requested by the 3R principle (Replacement, Refinement and Reduction).

Myocardial infarction still remains the main cause of death in western countries, despite considerable progress in the stent development area in the last ...

Surgical Models of Gastroesophageal Reflux with Mice

Multiple surgical procedures have been reported to induce gastroesophageal reflux in animals. Herein, we report three surgical models with mice aiming to induce reflux of gastric contents, duodenal contents or mixed contents. Surgical procedures and general principles have been described in detail. A researcher with surgical experience should be able to grasp the technique after a short period of practice. After surgery, most mice can survive and develop reflux esophagitis similar to that in humans. However, it should be noted that histological differences between mouse and human esophagus are the inherent limitations of these surgical models. If used for research on Barrett&#8217;s esophagus and adenocarcinoma, these procedures may need to be combined with genetic modifications.

This article demonstrates surgical procedures of gastroesophageal reflux with mice. These models are useful tools for research on mechanisms and treatment of gastroesophageal reflux disease and potentially Barrett&#8217;s esophagus and esophageal adenocarcinoma.

Multiple surgical procedures have been reported to induce gastroesophageal reflux in animals. Herein, we report three surgical models with mice aiming to ...

An Improved Method for Rapid Intubation of the Trachea in Mice

Despite some anatomical and physiological differences, mouse models continue to be an essential tool for studying human lung disease. Bleomycin toxicity is a commonly used model to study both acute lung injury and fibrosis, and multiple methods have been developed for administering bleomycin (and other toxic agents) into the lungs. However, many of these approaches, such as transtracheal instillation, have inherent drawbacks, including the need for strong anesthetics and survival surgery. This paper reports a quick, reproducible method of intratracheal intubation that involves mild inhaled anesthesia, visualization of the trachea, and the use of a surrogate spirometer to confirm exposure. As a proof of concept, 8-12 week old C57BL/6 mice were administered either 2.0 U/kg of bleomycin or an equivalent volume of PBS, and both damage and fibrotic endpoints were measured post-exposure. This procedure allows researchers to treat a large cohort of mice in a relatively short period with little expense and minimal post-procedure care.

This article presents a rapid and simple method for administering bleomycin directly into the mouse trachea via intubation. Key advantages of this method are that it is highly reproducible, easy to master, and does not require specialized equipment or lengthy recovery times.

Despite some anatomical and physiological differences, mouse models continue to be an essential tool for studying human lung disease. Bleomycin toxicity ...

Induction of Accelerated Atherosclerosis in Mice: The "Wire-Injury" Model

Atherosclerosis is a proliferative fibro-inflammatory disease developing in the arterial wall, inducing a deficient blood flow or a lack of blood flow. Moreover, by rupture of the defective vascular wall, atherosclerosis induces occlusive thrombus formation, which represents the main cause of myocardial infarction or stroke and the most frequent cause of death. Despite the advances in the cardiovascular field, many questions remain unanswered, and additional basic research is essential to improve our understanding of the molecular mechanisms during atherosclerosis and its effects. Due to limited clinical studies, there is a need for representative animal models recreating atherosclerotic conditions such as neointima formation after stent implantation, balloon angioplasty, or endarterectomy. Since the mouse presents many advantages and is the most frequently used model for studying molecular processes, the current study proposes an invasive procedure of endothelial denudation, also known as the wire-injury model, which is representative of the human condition of neointima formation in arteries after revascularization procedures.

Induction of Accelerated Atherosclerosis in Mice: The &quot;Wire-Injury&quot; Model

This study describes an invasive procedure for the induction of accelerated atherosclerosis in mice. In comparison to other methods using electric- or cryo-induced injury, mechanical-induced injury mimics the human condition of restenosis after revascularization therapies and is ideal for the study of the molecular mechanisms involved.

Atherosclerosis is a proliferative fibro-inflammatory disease developing in the arterial wall, inducing a deficient blood flow or a lack of blood flow. ...

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.

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 ...

Inducing Acute Lung Injury in Mice by Direct Intratracheal Lipopolysaccharide Instillation

Airway administration of lipopolysaccharide (LPS) is a common way to study pulmonary inflammation and acute lung injury (ALI) in small animal models. Various approaches have been described, such as the inhalation of aerosolized LPS as well as nasal or intratracheal instillation. The presented protocol describes a detailed step-by-step procedure to induce ALI in mice by direct intratracheal LPS instillation and perform FACS analysis of blood samples, bronchoalveolar lavage (BAL) fluid, and lung tissue. After intraperitoneal sedation, the trachea is exposed and LPS is administered via a 22 G venous catheter. A robust and reproducible inflammatory reaction with leukocyte invasion, upregulation of proinflammatory cytokines, and disruption of the alveolo-capillary barrier is induced within hours to days, depending on the LPS dosage used. Collection of blood samples, BAL fluid, and lung harvesting, as well as the processing for FACS analysis, are described in detail in the protocol. Although the use of the sterile LPS is not suitable to study pharmacologic interventions in infectious diseases, the described approach offers minimal invasiveness, simple handling, and good reproducibility to answer mechanistic immunological questions. Furthermore, dose titration as well as the use of alternative LPS preparations or mouse strains allow modulation of the clinical effects, which can exhibit different degrees of ALI severity or early vs. late onset of disease symptoms.

Presented here is a step-by-step procedure to induce acute lung injury in mice by direct intratracheal lipopolysaccharide instillation and to perform FACS analysis of blood samples, bronchoalveolar lavage fluid, and lung tissue. Minimal invasiveness, simple handling, good reproducibility, and titration of disease severity are advantages of this approach.

Airway administration of lipopolysaccharide (LPS) is a common way to study pulmonary inflammation and acute lung injury (ALI) in small animal models. ...

A Revised Method for Inducing Secondary Lymphedema in the Hindlimb of Mice

Animal models are of paramount importance in the research of lymphedema in order to understand the pathophysiology of the disease but also to explore potential treatment options. This mouse model allows researchers to induce significant lymphedema lasting at least 8 weeks. Lymphedema is induced using a combination of fractioned radiotherapy and surgical ablation of lymphatics. This model requires that the mice get a dose of 10 Gray (Gy) radiation before and after surgery. The surgical part of the model involves ligation of three lymph vessels and extraction of two lymph nodes from the mouse hindlimb. Having access to microsurgical tools and a microscope is essential, due to the small anatomical structures of mice. The advantage of this model is that it results in statistically significant lymphedema, which provides a good basis for evaluating different treatment options. It is also a great and easily available option for microsurgical training. The limitation of this model is that the procedure can be time consuming, especially if not practiced in advance. The model results in objectively quantifiable lymphedema in mice, without causing severe morbidity and has been tested in three separate projects.

This animal model enables researchers to induce statistically significant secondary lymphedema in the hindlimb of mice, lasting at least 8 weeks. The model can be used to study the pathophysiology of lymphedema and to investigate novel treatment options.

Animal models are of paramount importance in the research of lymphedema in order to understand the pathophysiology of the disease but also to explore ...

Real-Time Monitoring of Cellular Dynamics in Mouse Lung Transplantation

Intravital Two-Photon Microscopy of the Transplanted Mouse Lung

Complications after lung transplantation are largely related to the host immune system responding to the graft. Such immune responses are regulated by crosstalk between donor and recipient cells. A better understanding of these processes relies on the use of preclinical animal models and is aided by an ability to study intra-graft immune cell trafficking in real-time. Intravital two-photon microscopy can be used to image tissues and organs for depths up to several hundred microns with minimal photodamage, which affords a great advantage over single-photon confocal microscopy. Selective use of transgenic mice with promoter-specific fluorescent protein expression and/or adoptive transfer of fluorescent dye-labeled cells during intravital two-photon microscopy allows for the dynamic study of single cells within their physiologic environment. Our group has developed a technique to stabilize mouse lungs, which has enabled us to image cellular dynamics in na&#239;ve lungs and orthotopically transplanted pulmonary grafts. This technique allows for detailed assessment of cellular behavior within the vasculature and in the interstitium, as well as for examination of interactions between various cell populations. This procedure can be readily learned and adapted to study immune mechanisms that regulate inflammatory and tolerogenic responses after lung transplantation. It can also be expanded to the study of other pathogenic pulmonary conditions.

Author Spotlight: Advancing Lung Transplant Immunology Through Intravital Imaging

Here, we present a protocol to intravitally image the transplanted mouse left lung using two-photon microscopy. This represents a valuable tool for studying cellular dynamics and interactions in real-time following murine lung transplantation.

Complications after lung transplantation are largely related to the host immune system responding to the graft. Such immune responses are regulated by ...