The authors thank Guangdong Laboratory Animals Monitoring Institute for technical support, animal care, and sample collection. They also thank Shenzhen Mindray Bio-Medical Electronics Co., Ltd, for technical support in the ultrasonic examination. This work was supported by Guangdong Science and Technology Program, China, and Jinan University Central Universities Basic Scientific Research Business Expenses Project (2017A020215076, 2008A08003, and 21621409).

The procedures for the care and use of laboratory animals were approved by the Institutional Animal Care and Use Committee of the Guangdong Laboratory Animals Monitoring Institute. All experiments were conducted in accordance with the Guide for the Care and Use of Laboratory Animals (8th Ed., 2011, National Research Council, USA). The surgical procedure is shown in Figure 1.
1. Preoperative preparation of animals
<ol>
	<li>Randomly divide 10 3-m...

<ol>
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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=Antisense+oligonucleotides+to+c-fos+and+c-jun+inhibit+intimal+thickening+in+a+rat+vein+graft+model.">Antisense oligonucleotides to c-fos and c-jun inhibit intimal thickening in a rat vein graft model.</a> Surgery. 126 (2), 443-449 (1999).</li><li>Jiang, Z., 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+novel+vein+graft+model:+Adaptation+to+differential+flow+environments.">A novel vein graft model: Adaptation to differential flow environments.</a> American Journal of Physiology. Heart and Circulatory Physiology. 286 (1), H240-H245 (2004).</li><li>O'Brien, J. 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The authors have no conflicts of interest to disclose.

In this study, we described in detail the protocol for animal selection, instrument preparation, surgical procedures, and post-operative evaluation when developing a CABG-induced VGD model. We performed ultrasonic examination of the venous graft before and after CABG surgery and histological examination of the graft 30 days after the surgery. The blood flow in the internal mammary vein was normal before the CABG surgery, while retrograde flow was observed in the graft of the internal mammary vein. Compared with the sham ...

Although coronary heart disease mortality has declined significantly in recent years, half of middle-aged adults in the United States develop ischemic heart-related symptoms each year, and one-third of older adults die from coronary heart disease1. Coronary artery bypass grafting (CABG) is an effective surgical modality to improve myocardial ischemia, and more importantly, it is an irreplaceable surgical modality for the treatment of multivessel coronary artery disease2. Over time, however, vascular grafts develop inflammation, intimal hyperplasia, and progressive atherosclerosis, which is known to lead to vein graft failure or vein graft disease (VGD)3. In patients after CABG, if restenosis occurs, only the diseased blood vessel can be replaced in some cases2. Older patients and added comorbidities make redoing coronary artery bypass grafting quite challenging. Delaying or controlling the pathological problems associated with grafted blood vessels is an urgent problem to be solved. Large animal models of CABG-VGD are needed for the investigation of disease mechanisms and the development of therapeutic strategies. Researchers have successfully established animal VGD models in small and large animals such as mice4, rats5, rabbits6, and pigs7. Compared with small animals, large animals such as pigs have anatomical structures and physiological characteristics similar to humans and have longer lifespans8,9. Thus, large animals are more suitable for exploring long-term pathological changes in venous graft disease and for preclinical testing of drugs or devices. We and our collaborating team have successfully applied surgical techniques to establish a porcine heart failure model and described the cardiac pathological changes in this model10.
CABG surgery has been standardized in clinical practice, but when it is applied to the establishment of VGD animal models, the differences between species, the acquisition of animal equipment and facilities, animal surgical operations, and animal feeding and nursing are huge challenges for researchers. As in clinical practice, the approaches for CABG surgery used to establish VGD animal models include midline sternotomy11 and left lateral thoracotomy12. Midline sternotomy is more commonly used13,14. However, this approach has high risks for both humans and animals. In the study reported by Thankam et al., two of the six pigs used for modeling died during surgery15. High model mortality increases study costs and affects the accuracy of results. A study showed earlier that a left chest wall incision was feasible to establish CABG-induced VGD in pigs11. Here, this study aims to describe a step-by-step protocol to establish a reproducible surgery for a CABG-induced VGD model in minipigs and to evaluate the phenotype of this model. The experimental protocol was jointly designed by the cardiac surgery and anesthesia teams. The surgical approach for the left third intercostal space was determined according to the cadavers of other minipigs in the laboratory before surgery, and the anesthesia method was performed according to the method used at the center16. Blood biochemical tests, ultrasonic examination, and histology examination were conducted to evaluate animal models.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Aortic Punch</td>
			<td>Medtronic Inc. , America</td>
			<td>3.0mm, 3.5mm, 4.0mm</td>
			<td>Used for proximal coronary bridge anastomosis</td>
		</tr>
		<tr>
			<td>Automatic biochemical analyzer</td>
			<td>IDEXX Laboratories, Inc. America</td>
			<td>Catalyst One</td>
			<td></td>
		</tr>
		<tr>
			<td>Cardiac coronary artery bypass grafting instrument kit</td>
			<td>LANDANGER, France</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Cardiogram monitor</td>
			<td>Shenzhen Mindray Bio-Medical Electronics Co, Ltd</td>
			<td>MEC-1000</td>
			<td></td>
		</tr>
		<tr>
			<td>Coronary Shunt</td>
			<td>AXIUS&#160;</td>
			<td>OF-1500, OF-2500, OF-3000</td>
			<td>The product temporarily blocks the coronary artery during arteriotomy to reduce the amount of bleeding in the surgical field and provide blood flow to the distal end during anastomosis.&#160; The Axius shunt plug is not an implant and should be removed prior to completion of the anastomosis.&#160;&#160;</td>
		</tr>
		<tr>
			<td>Defibrillator</td>
			<td>MEDIANA</td>
			<td>Mediana D500</td>
			<td></td>
		</tr>
		<tr>
			<td>Diazepam</td>
			<td>Nanguo pharmaceutical Co. LTD, Guangdong, China</td>
			<td>H37023039&#160;</td>
			<td>Narcotic inducer</td>
		</tr>
		<tr>
			<td>Disposable manual electric knife</td>
			<td>Covidien, America</td>
			<td>E2516H</td>
			<td></td>
		</tr>
		<tr>
			<td>Electric negative pressure suction machine</td>
			<td>Shanghai Baojia Medical Instrument Co, Ltd</td>
			<td>YX932D</td>
			<td></td>
		</tr>
		<tr>
			<td>Esmolol</td>
			<td>Guangzhou Wanzheng Pharmaceutical Co. LTD</td>
			<td>H20055990</td>
			<td>Emergency drugs</td>
		</tr>
		<tr>
			<td>Ice machine&#160;</td>
			<td>Local suppliers, Guangzhou, China</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Lidocaine&#160;</td>
			<td>Chengdu First Pharmaceutical Co. LTD</td>
			<td>H51021662</td>
			<td>Emergency drugs</td>
		</tr>
		<tr>
			<td>Luxtec headlight system</td>
			<td>Luxtec, America</td>
			<td>AX-1375-BIF</td>
			<td>Used for lighting fine parts during operation</td>
		</tr>
		<tr>
			<td>Medical operation magnifier (glasses)</td>
			<td>Germany Lista co, LTD</td>
			<td>SuperVu Galilean 3.5&#215;</td>
			<td>Used for fine site operation during operation</td>
		</tr>
		<tr>
			<td>Multi-function high-frequency electrotome</td>
			<td>Shanghai Hutong Electronics Co, Ltd</td>
			<td>GD350-B</td>
			<td></td>
		</tr>
		<tr>
			<td>Nitrogen canister</td>
			<td>Local suppliers, Guangzhou, China</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Nonabsorbable surgical suture (polypropylene suture)</td>
			<td>Johnson &#38; Johnson, America</td>
			<td>6-0, 7-0</td>
			<td>Used to suture blood vessels.</td>
		</tr>
		<tr>
			<td>Nonabsorbable suture (cotton thread)</td>
			<td>Covidien, America</td>
			<td>1-0</td>
			<td>Used for skin and muscle tissue tugging</td>
		</tr>
		<tr>
			<td>Open heart surgery instrument kit</td>
			<td>Shanghai Medical Instrument (Group) Co., LTD</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Propofol injection</td>
			<td>Xi &#39;an Libang Pharmaceutical Co. LTD</td>
			<td>H19990282</td>
			<td>Anesthetic sedative</td>
		</tr>
		<tr>
			<td>Refrigerator</td>
			<td>Local suppliers, Guangzhou, China</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Respiratory anesthesia machine for animal</td>
			<td>Shenzhen Reward Life Technology Co, Ltd, China</td>
			<td>R620-S1</td>
			<td></td>
		</tr>
		<tr>
			<td>Semi-occlusion clamp</td>
			<td>Xinhua Surgical Instrument Co., Ltd.</td>
			<td>ZL1701RB</td>
			<td>Temporarily cut off the aortic flow</td>
		</tr>
		<tr>
			<td>vecuronium bromide</td>
			<td>Richter, Hungary&#160;</td>
			<td>JX20090127</td>
			<td>Muscle relaxant</td>
		</tr>
		<tr>
			<td>Veterinary ultrasound system&#160;</td>
			<td>Royal Philips, Netherlands</td>
			<td>CX50</td>
			<td></td>
		</tr>
		<tr>
			<td>Zoletil</td>
			<td>Virbac, France</td>
			<td>Zoletil 50&#160;</td>
			<td>Animal narcotic</td>
		</tr>
	</tbody>
</table>

establishment and evaluation of a porcine vein graft disease model

Venous graft disease (VGD) is the leading cause of coronary artery bypass graft (CABG) failure. Large animal models of CABG-VGD are needed for the investigation of disease mechanisms and the development of therapeutic strategies. 
To perform the surgery, we enter the cardiac chamber through the third intercostal space and carefully dissect the internal mammary vein and immerse it in normal saline. The right main coronary artery is then treated for ischemia. The target vessel is incised, a shunt plug is placed, and the distal end of the graft vein is anastomosed. The ascending aorta is partially blocked, and the proximal end of the graft vein is anastomosed after perforation. The graft vein is checked for patency, and the proximal right coronary artery is ligated. 
CABG surgery is performed in minipigs to harvest the left internal mammary vein for its use as a vascular graft. Serum biochemical tests are used to evaluate the physiological status of the animals after surgery. Ultrasound examination shows that the proximal, middle, and distal end of the graft vessel are unobstructed. In the surgical model, turbulent blood flow in the graft is observed upon histological examination after the CABG surgery, and venous graft stenosis associated with intimal hyperplasia is observed in the graft. The study here provides detailed surgical procedures for the establishment of a repeatable CABG-induced VGD model.

BMI and serum biochemical indices 
The BMI between the sham and VGD groups was not significantly different (sham vs. VGD, 22.05 kg/cm2 &#177; 0.46 kg/cm2 vs. 21.14 kg/cm2 &#177; 0.39 kg/cm2, p = 0.46). The serum biochemical results&#160;are listed in Table 1. Statistically significant changes between the groups were found in four biochemical indexes, including aspartate aminotransferase (AST, sham vs. VGD, 25.25 IU/L &#177; 1.88 I...

Watch this Scientific Journal Video about Establishment and Evaluation of a Porcine Vein Graft Disease Model at JoVE.com

Establishment and Evaluation of a Porcine Vein Graft Disease Model

In this protocol, novel pig vein bypass grafting was performed through a small incision in the left chest wall without cardiopulmonary bypass. A postoperative pathology study was done, which showed intimal thickening.

Venous graft disease (VGD) is the leading cause of coronary artery bypass graft (CABG) failure. Large animal models of CABG-VGD are needed for the ...

This model provides a standard protocol for establishing animal models of coronary graft disease. The procedure of animal model established by this method is standard, and the result is stable. To begin, divide three-month-old, male minipigs weighing 30 to 35 kilograms into the sham and venous graft disease groups of five animals each.After anesthetizing the animal, establish ear access by inserting an indwelling venous catheter into the marginal ear vein. Now, transfer the pig onto the operation table in the supine position. Perform tracheal intubation with a 7.0 to 7.5 French gauge tube, and connect it to the anesthesia breathing circuit.Immobilize the limbs with bandages, and elevate the head with a sterile drape. After injecting vecuronium bromide intravenously for muscle relaxation, monitor heart rate, blood oxygen levels, and body temperature using an electrocardiogram. After shaving and sterilizing the surgical area, place a sterile surgical drape around it.After making the incision and exposing the internal mammary vein as described in the text, locate the internal mammary vein and the left internal mammary artery on the left side of the sternum, and perform blunt dissection of the internal mammary vein with vascular forceps. Perform hemostasis by electrocoagulation of the left internal mammary vein branches with an electric knife. If hemostasis is incomplete, using cotton thread, ligate and mark the two ends of the vein while it is being harvested.Once the vein is removed, inject heparin, normal saline into the vein for pre-treatment. Then, put the vein into the normal saline, keep it for backup, and similarly incise the internal mammary vein of the sham group. Then, open the pericardium, close the chest wall, and use the internal mammary vein for pathological control without coronary artery bypass grafting.Make an approximately seven-centimeter incision with an electric knife on the pericardium to expose the right coronary artery trunk. Suspend the pericardium, and sew the skin on the ipsilateral side with 1-0 surgical sutures. Now, separate the right coronary artery trunk from the surrounding tissues.Next, using a wire hook, bypass the blocking band under the proximal end of the isolated right coronary artery near the aorta. Then, treat the myocardium with three cycles of two minutes ischemia and five minutes reperfusion by tightening and relaxing the blocking band. Also, monitor the heart's electrical activity with the electrocardiogram during the ischemia reperfusion pre-conditioning.Next, cut the epicardium covering the blood vessels after tightening the band to block the right coronary blood flow. Exposing the coronary artery wall, cut longitudinally with the tip of a surgical blade against the center of the anterior wall of the blood vessels. After cutting the lumen and enlarging the incision and placing a coronary shunt, insert one end of the shunt with a coil into the distal coronary artery through the tear.Now, shunt the blood in the coronary arteries into the hollow coronary shunt to ensure a clear operative field, and perform an end-to-side continuous suture between the internal mammary vein and the aortic wall with the 6-0 polypropylene suture. In the middle of the ascending aorta, occlude the left anterolateral wall of the ascending aorta with a semi-occlusion clamp. After making a small incision with the surgical blade in the aortic wall where the adventitia has been cut, insert the head end of the sliding shaft at the head end of the punch into the aortic cavity through this incision.Then, contract the sliding shaft outward and the circular knife cuts off a piece of the arterial wall. Once the shunt is pulled out, perform an end-to-side continuous suture between the internal mammary vein and the right coronary artery with the 6-0 polypropylene suture. After opening the semi-occlusion clamp, record the bypass flow of the right coronary artery trunk proximal to the anastomosis site using ultrasound.Prepare the animal for surgery as demonstrated earlier. And with an electric knife, make a 10-centimeter median sternal incision to split the sternum and harvest the vein 30 days post-surgery. While separation, avoid the main blood vessels, heart, and separate the grafted blood vessels layer by layer.Quickly cut off the large blood vessels connecting to the heart, and place the heart and ascending aorta on ice chips. Once the graft vascular bridge, the connected aorta, and the right coronary artery are removed, rinse all the samples with normal saline at four degrees Celsius. After taking the entire graft vessel of about three to four centimeters and dividing it into four to five equal parts, transfer it to CryoTubes to quickly flash-freeze in liquid nitrogen.For analysis, fix the ice-cold, saline-rinsed graft in 4%paraformaldehyde solution. After 12 hours of tissue fixation, stain the sections in 50 milliliters of an aqueous solution of hematoxylin for three minutes. Then, separate the sections by washing with 50 milliliters of 0.5%hydrochloric acid-ethanol and 0.2%ammonia water for 10 seconds each.Once the sections are rinsed for one hour with running water, clean them by soaking them in distilled water for three minutes. After dehydrating the sections in 70%and 90%ethanol for 10 minutes, place them in 50 milliliters of 0.5%alcohol eosin staining solution for two to three minutes. Once the stained sections are dehydrated in pure ethanol, soak the samples in pure xylene for 10 minutes to make them transparent.Finally, drip the transparent sections with neutral glue before covering them with a cover slip. Observe pathological sections under a light microscope at 40 times magnification. Ultrasonic examination showed that the overall blood flow direction was normal in the proximal end, vascular cavity, and the distal end of the graft vessel.However, the proximal and distal ends of the graft vessel showed some retrograde flow of blood. The histological analysis of the internal mammary vein revealed that in the sham group the tunica intima, tunica media, and the venous wall of the venous graft appeared normal. However, 30 days after coronary artery transplantation, the intima of the vessel was thickened and the lumen was narrowed.Among the sham and venous graft disease groups, four biochemical indexes, aspartate aminotransferase, serum bilirubin, total bilirubin, and creatinine, showed statistically significant changes. The surgeon should completely expose the internal mammary vein and make sure it is not attached to the surrounding tissue. The technique provides a standardized modeling process for studying venous graft diseases in animal models.

establishment-and-evaluation-of-a-porcine-vein-graft-disease-model

Research

JoVE Journal

Medicine

1.6K 조회수.  the First Affiliated Hospital of Jinan University. 이 모델은 관상동맥 이식편 질환의 동물 모델을 확립하기 위한 표준 프로토콜을 제공한다. 이 방법으로 확립 된 동물 모델의 절차는 표준이며 결과는 안정적입니다. 먼저 체중이 30-35kg인 생후 3개월 된 수컷 미니돼지를 각각 5마리씩 가짜 및 정맥 이식 질환 그룹으로 나눕니다.동물을 마취 한 후, 유치 정맥 카테터를 가장자리 귀 정맥에 삽입하여 귀 접근을 설정하십시오...