The authors are solely responsible for the design and conduct of the presented study. Dr. Marbacher was supported by a grant from the Swiss National Science Foundation (PBSKP3-123454). The authors declare no conflict of interests. 
Author contributions to the study and manuscript preparation include the following. Conception and design: SM, JM, JF. Acquisition of data: SM, EA, JF. Analysis and interpretation of data: SM, JF, JM. Drafting the article: SM, JF, JM. Critically revising the article: JH, MN. Statistical analysis: SM, JF. Study supervision: JF, JH, MN.

NOTE: Male Wistar rats (mean body weight: 356 &#177; 44 g; 10-14 weeks old) were housed in the animal room at 22-24 &#176;C and twelve hour light/dark cycle with free access to pellet diet, regular tap water and also received humane care in conformity with institutional guidelines. The experiments were reviewed and approved by the Committee for Animal Welfare at the University of Helsinki, Finland. &#160;
NOTE: In the following demonstration our surgical method is as follows: Anesthetize the r...

<ol>
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The authors have no financial or commercial interest in any of the drugs, materials, or equipment used.

Progress in our understanding of the complex biology of saccular cerebral artery aneurysm depends on analysis of epidemiological and clinical data, complemented by laboratory studies on patient samples and experimental work in animal models3,12,13.
Small animals such as the rat are inherently associated with lower costs of experiments and housing, and reduced need of specialized equipment. An average total operation time of less than 60 minutes for microsurgical creation of a sidewa...

Rupture of a saccular cerebral artery aneurysm causes life threatening hemorrhage leading to stroke, permanent neurological damage, or death. Rupture can be prevented by either microsurgical clipping or endovascular aneurysm occlusion. A medical treatment to prevent aneurysm growth and rupture has not yet been established.
Experimental models for saccular aneurysms are needed to study the biology of arterial aneurysms and for the testing of novel therapeutic devices and strategies. For these purposes, several different models in different species have been developed and published1. Larger aneurysm models in pigs, dogs, and rabbits are preferably used to test endovascular innovations in complex aneurysm architecture1,2. Murine aneurysm models, on the other hand, allow testing research questions in genetically modified species3,4 and facilitate clarification of aneurysm biology at cellular and molecular level far better than larger species1. Although endovascular trans-carotid and trans-iliac device deployment is limited to bigger rats (&#62;400-500 g) and stents smaller than 2.0 mm and 1.5 mm in diameter5,6, stents can also be placed through direct insertion into the abdominal aortic segment harbouring the experimental aneurysms. Previous work using the rat microsurgical abdominal aortic sidewall aneurysm model demonstrated its feasibility in testing novel embolic devices and its use in studying the molecular basis of aneurysm biology3,7.
Many of the currently published experimental saccular aneurysm models require expensive equipment, special environments (e.g. sterile operation rooms with fluoroscopy capabilities), interventional radiology competence, or use of expensive species. These requirements limit the widespread use of these models, and lead to the use of different models in different laboratories, which makes data comparison and meta-analysis difficult, if not impossible. A simple, robust, and inexpensive experimental model is needed as a standardized tool that can be used in a standardized manner in various labs in order to get comparable results from different institutions. For this purpose, we created the rat aorta sidewall saccular arterial aneurysm model.
The aim of this report is to present step-by-step procedural instructions, information on necessary equipment, and to discuss important anatomical and surgical characteristics for successful microsurgical creation of abdominal aortic sidewall aneurysms in the rat.

<table border="0" cellpadding="0" cellspacing="0" width="752">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">Name of Material/ Equipment</td>
			<td style="width:236px;">Company</td>
			<td style="width:119px;">Catalog Number</td>
			<td style="width:167px;">Comments/Description</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">Medetomidine</td>
			<td style="width:236px;"></td>
			<td style="width:119px;"></td>
			<td>Any genericon</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">Ketamin</td>
			<td style="width:236px;"></td>
			<td style="width:119px;"></td>
			<td>Any genericon</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">Buprenorphine</td>
			<td style="width:236px;"></td>
			<td style="width:119px;"></td>
			<td>Any genericon</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">Phosphate buffered saline</td>
			<td style="width:236px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">Sodium dodecyl sulfate (0.1%)</td>
			<td style="width:236px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">3-0 resorbable suture</td>
			<td style="width:236px;">Ethicon Inc., USA</td>
			<td><a name="RANGE!C7">VCP824G</a></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">5-0 non absorbable suture</td>
			<td style="width:236px;">Ethicon Inc., USA</td>
			<td>8618G</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">6-0 non absorbable silk suture</td>
			<td style="width:236px;">B. Braun, Germany</td>
			<td style="width:119px;">C0761060</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">9-0 nylon micro suture</td>
			<td style="width:236px;">B. Braun, Germany</td>
			<td style="width:119px;">G1118471</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">Spongostan</td>
			<td style="width:236px;">Ethicon Inc., USA</td>
			<td style="width:119px;">MS0002</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">Operation microscope</td>
			<td style="width:236px;">Leica , Germany</td>
			<td style="width:119px;">M651</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">Digital microscope camera</td>
			<td style="width:236px;">Sony, Japan</td>
			<td style="width:119px;">SSC-DC58AP</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">Standard surgical instruments</td>
			<td style="width:236px;">B. Braun, Germany</td>
			<td style="width:119px;">Multiple</td>
			<td>See protocol 1.4</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">Microsurgical instruments</td>
			<td style="width:236px;">B. Braun, Germany</td>
			<td style="width:119px;">Multiple</td>
			<td>See protocol 1.5</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">Vascular clip applicator</td>
			<td style="width:236px;">B. Braun, Germany</td>
			<td style="width:119px;">FT495T</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">Temporary vascular clamps</td>
			<td style="width:236px;">B. Braun, Germany</td>
			<td style="width:119px;">FT250T</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">Graph Pad Prism statistical software&#160;</td>
			<td style="width:236px;">GraphPad Software, San Diego, California, USA</td>
			<td style="width:119px;"></td>
			<td>V 6.02 for Windows</td>
		</tr>
	</tbody>
</table>

the helsinki rat microsurgical sidewall aneurysm model

Experimental saccular aneurysm models are necessary for testing novel surgical and endovascular treatment options and devices before they are introduced into clinical practice. Furthermore, experimental models are needed to elucidate the complex aneurysm biology leading to rupture of saccular aneurysms.
Several different kinds of experimental models for saccular aneurysms have been established in different species. Many of them, however, require special skills, expensive equipment, or special environments, which limits their widespread use. A simple, robust, and inexpensive experimental model is needed as a standardized tool that can be used in a standardized manner in various institutions.
The microsurgical rat abdominal aortic sidewall aneurysm model combines the possibility to study both novel endovascular treatment strategies and the molecular basis of aneurysm biology in a standardized and inexpensive manner. Standardized grafts by means of shape, size, and geometry are harvested from a donor rat&#39;s descending thoracic aorta and then transplanted to a syngenic recipient rat. The aneurysms are sutured end-to-side with continuous or interrupted 9-0 nylon sutures to the infrarenal abdominal aorta.
We present step-by-step procedural instructions, information on necessary equipment, and discuss important anatomical and surgical details for successful microsurgical creation of an abdominal aortic sidewall aneurysm in the rat.

A pilot series comprised 14 rats. Subsequently a total of 84 animals were operated according to the presented protocol for several research projects between March and September 2012. Additional 29 animals served as donors for arterial saccular grafts. The remaining experiments were performed using pre-treated grafts harvested and stored from previous experiments using rats of the same gender, strain, weight, and age.
Body weight, overall operation time, aortic clamping time, time for anastomos...

Watch this Scientific Journal Video about The Helsinki Rat Microsurgical Sidewall Aneurysm Model at JoVE.com

The Helsinki Rat Microsurgical Sidewall Aneurysm Model

Microsurgical sidewall aneurysms in rats are created by end-to-side anastomosis of an aortic graft to the abdominal aorta. We present step-by-step instructions and discuss anatomical and surgical details for successful experimental saccular aneurysm creation.

Experimental saccular aneurysm models are necessary for testing novel surgical and endovascular treatment options and devices before they are introduced ...

the-helsinki-rat-microsurgical-sidewall-aneurysm-model

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JoVE Journal

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12.1K visualizações.  University of Helsinki, Helsinki, Finland. Microsurgical sidewall aneurysms in rats are created by end-to-side anastomosis of an aortic graft to the abdominal aorta. We present step-by-step instructions and discuss anatomical and surgical details for successful experimental saccular aneurysm creation.