This work was supported by AI101263 from the National Institutes of Health (T.V.B), and by a grant from The Hartwell Foundation (M.L.M). M.L.M. is a member of the Duke Comprehensive Cancer Center.

NOTE: All experimental procedures involving the use of rats were done in accordance with protocols approved by the Animal Care and Use Committee of Duke University.
1. Preparation of the Tracheal Intubation Cannula
<ol>
	<li>Cut off the needle end of a 2 inch 14 G angiocathether needle with cutting pliers.</li>
	<li>Pinch the lumen of the needle closed with needle-nosed pliers.</li>
	<li>Cut the pinched section down to the edge of the open-lumen portion with cutting pliers, and then cut the ...

<ol>
	<li>Hard, G. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thymectomy+in+the+neonatal+rat.">Thymectomy in the neonatal rat.</a> Lab. Anim. 9 (2), 105-110 (1975).</li><li>Kobayashi, E., 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+technique+for+complete+thymectomy+in+adult+rats.">A technique for complete thymectomy in adult rats.</a> J. Immunol. Methods. 1759 (94), 0 (1994).</li><li>Delrivi&#232;re, L., Gibbs, P., Kobayashi, E., Kamada, N., Gianello, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+technique+of+complete+thymectomy+in+adult+rats+without+tracheal+intubation.">New technique of complete thymectomy in adult rats without tracheal intubation.</a> Microsurgery. 18 (1), 6-8 (1998).</li><li>Walker, K. G., Jacques, B. C., Tweedle, J. R., Bradley, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simpler+technique+for+open+thymectomy+in+adult+rats.">A simpler technique for open thymectomy in adult rats.</a> J. Immunol. Methods. 175 (1), 141 (1994).</li><li>Na, N., Zhao, D., Huang, Z., Hong, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+improved+method+for+rat+intubation+and+thymectomy.">An improved method for rat intubation and thymectomy.</a> Chin. Med. J. (Engl). 124 (17), 2723-2727 (2011).</li><li>Kastl, 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=Simplification+of+rat+intubation+on+inclined+metal+plate).">Simplification of rat intubation on inclined metal plate).</a> Adv. Physiol. Educ. 28 (1-4), 29-34 (2004).</li><li>Weksler, B., Ng, B., Lenert, J., Burt, M. <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+method+for+endotracheal+intubation+in+the+rat.">A simplified method for endotracheal intubation in the rat.</a> J. Appl. Physiol. 76 (4), 1823-1825 (1994).</li><li>Jou, I. 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=Simplified+rat+intubation+using+a+new+oropharyngeal+intubation+wedge.">Simplified rat intubation using a new oropharyngeal intubation wedge.</a> J. Appl. Physiol. 89 (5), 1766-1770 (2000).</li><li>Rivard, A. L., 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=Rat+intubation+and+ventilation+for+surgical+research.">Rat intubation and ventilation for surgical research.</a> J. Invest. Surg. 19 (4), 267-274 (2006).</li><li>Zhao, 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=A+model+of+isolated,+vascular+whole+thymus+transplantation+in+nude+rats.">A model of isolated, vascular whole thymus transplantation in nude rats.</a> Transplant Proc. 44 (5), 1394-1398 (2012).</li><li>AbuAttieh, 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=Affinity+maturation+of+antibodies+requires+integrity+of+the+adult+thymus.">Affinity maturation of antibodies requires integrity of the adult thymus.</a> Eur. J. Immunol. 42 (2), 500-510 (2012).</li><li>Reeves, J. P., Reeves, P. A., Chin, L. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Survival+surgery:+removal+of+the+spleen+or+thymus.">Survival surgery: removal of the spleen or thymus.</a> Curr. Protoc. Immunol. 1 (Unit 1.10), (2001).</li><li>Siemionow, M., Izycki, D., Ozer, K., Ozmen, S., Klimczak, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+thymus+in+operational+tolerance+induction+in+limb+allograft+transplant+model.">Role of thymus in operational tolerance induction in limb allograft transplant model.</a> Transplantation. 81 (11), 1568-1576 (2006).</li><li>Satoh, E., 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=Immunosuppressive+effect+of+long-term+drainage+of+thoracic+duct+on+immunological+memory+in+adult+thymectomized+rats.+Transplant.">Immunosuppressive effect of long-term drainage of thoracic duct on immunological memory in adult thymectomized rats. Transplant.</a> Proc. 37 (4), 1947-1948 (2005).</li><li>Groen, H., Klatter, F., Pater, J., Nieuwenhuis, P., Rozing, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temporary,+but+Essential+Requirement+of+CD8++T+Cells+Early+in+the+Pathogenesis+of+Diabetes+in+BB+Rats+as+Revealed+by+Thymectomy+and+CD8+Depletion.">Temporary, but Essential Requirement of CD8+ T Cells Early in the Pathogenesis of Diabetes in BB Rats as Revealed by Thymectomy and CD8 Depletion.</a> Clin. Dev. Immunol. 10 (2-4), 141-151 (2003).</li></ol>

The present protocol for complete thymectomy provides a minimally invasive approach with a three layer incision closure with surgical glue application designed to minimize complications. Complete removal of the thymus was demonstrated by the loss of na&#239;ve T cells and by IHC staining of mediastinal lymphoid tissue for cytokeratin.
The procedure of adult rat thymectomy has been complicated by mortality rates ranging from 1.5 - 20% due to peri-operative complications, most of which are the a...

Since the early 1960s, the thymus has been recognized for its critical role in the development of central immunological tolerance. Rodent thymectomy has proven to be an essential procedure in defining the role of the thymus in lymphocyte differentiation, self-tolerance, and immunotolerance in the setting of allograft transplantation and tumor metastasis. Removal of the rat thymus allows for studies involving T-cell depletion or the adoptive transfer of defined T cell populations without the re-emergence of native na&#239;ve T cells.
Thymectomies in neonatal rodents can be accomplished using a suction technique with reliable outcomes1. In adult rats, this technique is associated with an approximate 20% mortality rate and frequently results in an incomplete thymectomy2. To consistently achieve complete thymectomy in adult rats, open exposure of the mediastinum through a median sternotomy is required. However, this procedure is associated with complications that include tracheal injury, hemorrhage and pneumothorax leading to an overall mortality rate ranging from 1.5 - 6%2-4.
Over the last two decades improvements in thymectomy techniques have decreased perioperative complications and have improved survival rates. Endotracheal intubation allowing for positive pressure ventilation has lessened pneumothorax rates5. Methods of intubation previously described range from open exposure to the trachea to less invasive methods using direct vocal cord visualization. Complications associated with the intubation procedure include tracheal injury, vocal cord rupture, unintended esophageal intubation, and hemorrhage resulting from cardiac puncture or laceration of the superior vena cava. In addition, close proximity of the lower thymic lobes to the pleural lining can result in pneumothorax.
Here we describe a technique of thymectomy through a minimally invasive 2 cm skin incision following a simple method of endotracheal intubation using a blunted-end angiocatheter and transcutaneous tracheal illumination. The thymectomy involves a 1.5&#160;cm sternotomy and a three-layer closure with surgical glue application to seal the mediastinum and minimize the incidence of hemorrhage and respiratory complications. This method reliably results in complete thymectomy as evidenced by the disappearance of CD4+ and CD8+ na&#239;ve T cells following thymectomy and the absence of thymic tissue on IHC staining. Operative times and peri-procedural mortality are kept to a minimum.

<table border="0" cellpadding="0" cellspacing="0" width="718">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Name of Reagent/ Equipment</td>
			<td style="width:117px;">Company</td>
			<td style="width:152px;">Catalog Number</td>
			<td style="width:167px;">Comments/Description</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">2&#34; 14-gauge angiocatheter</td>
			<td style="width:117px;"></td>
			<td style="width:152px;"></td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Operating microscope</td>
			<td style="width:117px;">Zeiss</td>
			<td style="width:152px;"></td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Warming pad</td>
			<td style="width:117px;"></td>
			<td style="width:152px;"></td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:283px;">Heart rate and blood oxygenation monitor for rodents with foot sensors</td>
			<td style="width:117px;">Harvard Apparatus</td>
			<td style="width:152px;">ST1 72-8010, ST1 72-8098 (Rat foot sensor)</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:283px;">Intubation apparatus (plastic with metal bar at the top)</td>
			<td style="width:117px;"></td>
			<td style="width:152px;"></td>
			<td style="width:167px;">See Figure 2&#160;</td>
		</tr>
		<tr height="67">
			<td height="67" style="height:67px;width:283px;">Small animal anesthesia system with induction box, isoflurane tank and O2 tank</td>
			<td style="width:117px;">Harvard Apparatus</td>
			<td style="width:152px;">ST1 72-6420</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="105">
			<td height="105" style="height:105px;width:283px;">Small animal ventilator with tubing</td>
			<td style="width:117px;">CWE</td>
			<td style="width:152px;">12-02000 (ventilator)and 12-04000 (external valve assembly for mice/rats)</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">High-intensity Fiber-Optic Illuminator</td>
			<td style="width:117px;">Dolan Jenner</td>
			<td style="width:152px;">EEG 2823M</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:283px;">Student standard pattern forceps</td>
			<td style="width:117px;">Fine Science Tools</td>
			<td style="width:152px;">91100-16</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:283px;">Fine straight scissors</td>
			<td style="width:117px;">Fine Science Tools</td>
			<td style="width:152px;">14060-09</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:283px;">Blunt-tipped Shea scissors</td>
			<td style="width:117px;">Fine Science Tools</td>
			<td style="width:152px;">14105-12</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:283px;">Small Alm retractor (for sternum)</td>
			<td style="width:117px;">Fine Science Tools</td>
			<td style="width:152px;">17008-07</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:283px;">Blunt Graefe forceps</td>
			<td style="width:117px;">Fine Science Tools</td>
			<td style="width:152px;">11050-10</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:283px;">Fine Dumont forceps</td>
			<td style="width:117px;">Fine Science Tools</td>
			<td style="width:152px;">11254-20</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">5-0 Maxon sutures</td>
			<td style="width:117px;">Ethicon</td>
			<td style="width:152px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">4-0 Silk sutures (with cutting needle)</td>
			<td style="width:117px;">Ethicon</td>
			<td style="width:152px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">6-0 Nylon suture</td>
			<td style="width:117px;">Ethicon</td>
			<td style="width:152px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Cyanoacrylate glue (Endermil)</td>
			<td style="width:117px;"></td>
			<td style="width:152px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:283px;">Lubrication gel</td>
			<td style="width:117px;">Akorn Animal Health</td>
			<td style="width:152px;">NDC 17478-162-35</td>
			<td></td>
		</tr>
	</tbody>
</table>

complete thymectomy in adult rats with non-invasive endotracheal intubation

Thymectomy in neonatal rodents is an established and reliable procedure for immunological studies. However, in adult rats, complications of hemorrhage and pneumothorax from pleural disruption can result in a significant mortality rate. This protocol is a simple method of rat thymectomy that utilizes a mini-sternotomy and endotracheal intubation. Intubation is accomplished with a non-invasive and easily reproducible method and allows for positive pressure ventilation to prevent pneumothorax and a controlled airway that allows sufficient time for careful thymus dissection to minimize pleural disruption. A 1.5 cm sternal incision decreases contact with mediastinal vessels and pleura, while still providing full visualization of the thymus. Following exposure of the mediastinum, the thymus is removed by blunt dissection under magnification. The pleural space is then sealed by suture closure of the pre-tracheal muscles followed by the application of surgical glue. The thorax is then closed by suture closure of the sternum, followed by suture closure of the skin. All thymectomies were complete as evidenced by immunohistochemical (IHC) staining of mediastinal tissue, and absence of na&#239;ve T-cells by flow cytometry, and the procedure had a 96% survival rate. This method is suitable when complete thymectomy with minimal complications is desired for further immunological studies in athymic adult rats.

This procedure was performed on adult Lewis rats (n = 26). The mean operation time was 15 &#177; 3 min. There was no intraoperative mortality. The mean intubation time &#8211; from placement of rat on the intubation apparatus to establishment of ventilation &#8211; was 45 &#177; 5 sec. 24 rats had a full recovery from the operation with no evidence of respiratory difficulties or hemorrhage through post-operative day (POD) 14. One rat developed respiratory difficulty on POD 4 and underwent re-operation to explore the medi...

Watch this Scientific Journal Video about Complete Thymectomy in Adult Rats with Non-invasive Endotracheal Intubation at JoVE.com

Complete Thymectomy in Adult Rats with Non-invasive Endotracheal Intubation

Rodent thymectomy is a valuable technique in immunological research. Here, a protocol for complete thymectomy in adult rats using a mini-sternotomy along with non-invasive intubation and positive pressure ventilation to minimize perioperative morbidity and mortality is described.

Thymectomy in neonatal rodents is an established and reliable procedure for immunological studies. However, in adult rats, complications of hemorrhage and ...

complete-thymectomy-adult-rats-with-non-invasive-endotracheal

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Immunology and Infection

16.3K Aufrufe.  Duke University Medical Center. Rodent thymectomy is a valuable technique in immunological research. Here, a protocol for complete thymectomy in adult rats using a mini-sternotomy along with non-invasive intubation and positive pressure ventilation to minimize perioperative morbidity and mortality is described. 