This work was supported by the grant from the National Natural Science Foundation of China No. 81670269, No. 81500355 and No. 81500226.

This study was approved by the Central South University Ethics Committee for Animal Research from The Second Xiangya Hospital (Changsha, China). The manuscript was prepared according to ARRIVE (Animal Research: Reporting of In Vivo Experiments) guidelines12.
1. Material and animal
<ol>
	<li>Prepare required materials: 75% ethanol, adhesive tape, epilating agent, 2 mL tube, 1.0 mL syringe connected with needle (26G), electronic scale, heparin and saline (see Table of Materials).</li>
	<li>Animals: Prepare 10 Kunming mice, 6-8 weeks old and weighing 21.6-28.3&#160;g (see Table of Materials). Maintain mice in accordance with the Guide for the Care and Use of Laboratory Animals13.</li>
</ol>
2. Anesthesia and animal positioning
<ol>
	<li>Weigh the mouse to calculate the required dosage of anesthetic agent.</li>
	<li>Inject sodium pentobarbital (60 mg/kg) through intraperitoneal injection to induce general anesthesia14 (Figure 1). Apply a sterile eye lubrication ointment at the start of the procedure to prevent damage to exposed eyes. 
	NOTE: Mice are considered to be sufficiently anesthetized when showing no motor response to testing of the pedal withdrawal reflex, tail pinch, or abdominal skin pinch.</li>
	<li>Place the mouse in the operation table in a supine position and 2-4 cm away from the edge of the table to facilitate vein puncture (Figure 2). Fix the limbs in a comfortable position as shown in Figure 2. No intubation or mechanical ventilation is needed in the whole procedure.</li>
	<li>Apply epilating agent around the infraclavicular space with a cotton swab.</li>
	<li>Three minutes later, wash the epilating agent with a wet cotton swab to remove the fur and any visible dirt.</li>
	<li>Sterilize the infraclavicular space with 75% ethanol and then dry with clean gauze.</li>
</ol>
3. Subclavian vein puncture and blood collection
<ol>
	<li>Identify the location of the clavicle bone and superior sternal fossa with a finger.</li>
	<li>Locate the puncture site close to the middle of the clavicle bone and caudal to it. Put the left index finger lateral to the puncture site to fix the skin and subcutaneous tissue (Figure 3).</li>
	<li>Move the needle upward and cranially toward the superior sternal fossa. Once the needle enters the subcutaneous tissue, move the ring finger of the right hand backward to form negative pressure (Figure 3). 
	NOTE: During this step, the position of the operator&#180;s right hand should be slightly lower than the operation table to make the needle move upward and superior to the horizontal plane. That is why the animal is placed near the edge of the table.</li>
	<li>Move the syringe forward 3-4 mm but stop if there is no blood drain into the syringe. Then slowly draw back the syringe and keep negative pressure in it. In most occasions, the blood would enter the syringe when drawing back.</li>
	<li>Once the blood enters the syringe, fix the syringe and maintain negative pressure until the required volume (200 &#181;L) of blood is collected in the syringe.</li>
	<li>After blood collection, withdraw the puncture needle, and press the puncture site with a cotton swab slightly for 1-2 minutes to stop bleeding. Then, return mice to the cage. 
	NOTE: Occasionally, one could not obtain the blood at his/her first attempt. Adjust the direction of the needle laterally and repeat steps 3.3-3.5. If 3 attempts fail to obtain blood sample, switch to the other side.</li>
	<li>Transfer the blood sample into a heparinized tube.</li>
</ol>
4. Mice recovery
<ol>
	<li>While the pentobarbital anesthesia is in effect, speed recovery by providing heat support until the mouse is moving again.</li>
</ol>

<ol>
	<li>McCosh, R. B., Kreisman, M. J., Breen, K. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Frequent+Tail-tip+Blood+Sampling+in+Mice+for+the+Assessment+of+Pulsatile+Luteinizing+Hormone+Secretion.">Frequent Tail-tip Blood Sampling in Mice for the Assessment of Pulsatile Luteinizing Hormone Secretion.</a> Journal of Visualized Experiments. (137), (2018).</li><li>Regan, R. D., Fenyk-Melody, J. E., Tran, S. M., Chen, G., Stocking, K. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+Submental+Blood+Collection+with+the+Retroorbital+and+Submandibular+Methods+in+Mice+(Mus+musculus).">Comparison of Submental Blood Collection with the Retroorbital and Submandibular Methods in Mice (Mus musculus).</a> Journal of the American Association for Laboratory Animal Science. 55 (5), 570-576 (2016).</li><li>Park, A. Y., 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=Blood+collection+in+unstressed,+conscious,+and+freely+moving+mice+through+implantation+of+catheters+in+the+jugular+vein:+a+new+simplified+protocol.">Blood collection in unstressed, conscious, and freely moving mice through implantation of catheters in the jugular vein: a new simplified protocol.</a> Physiological Reports. 6 (21), e13904 (2018).</li><li>Heimann, M., Kasermann, H. P., Pfister, R., Roth, D. R., Burki, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Blood+collection+from+the+sublingual+vein+in+mice+and+hamsters:+a+suitable+alternative+to+retrobulbar+technique+that+provides+large+volumes+and+minimizes+tissue+damage.">Blood collection from the sublingual vein in mice and hamsters: a suitable alternative to retrobulbar technique that provides large volumes and minimizes tissue damage.</a> Laboratory Animals. 43 (3), 255-260 (2009).</li><li>Parasuraman, S., Raveendran, R., Kesavan, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Blood+sample+collection+in+small+laboratory+animals.">Blood sample collection in small laboratory animals.</a> Journal of Pharmacology &amp; Pharmacotherapeutics. 1 (2), 87-93 (2010).</li><li>Diehl, K. 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=A+good+practice+guide+to+the+administration+of+substances+and+removal+of+blood,+including+routes+and+volumes.">A good practice guide to the administration of substances and removal of blood, including routes and volumes.</a> Journal of Applied Toxicology. 21 (1), 15-23 (2001).</li><li>van Herck, 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=Orbital+sinus+blood+sampling+in+rats+as+performed+by+different+animal+technicians:+the+influence+of+technique+and+expertise.">Orbital sinus blood sampling in rats as performed by different animal technicians: the influence of technique and expertise.</a> Laboratory Animals. 32 (4), 377-386 (1998).</li><li>Tsai, P. 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=Effects+of+different+blood+collection+methods+on+indicators+of+welfare+in+mice.">Effects of different blood collection methods on indicators of welfare in mice.</a> Lab Anim (NY). 44 (8), 301-310 (2015).</li><li>Holmberg, H., Kiersgaard, M. K., Mikkelsen, L. F., Tranholm, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impact+of+blood+sampling+technique+on+blood+quality+and+animal+welfare+in+haemophilic+mice.">Impact of blood sampling technique on blood quality and animal welfare in haemophilic mice.</a> Laboratory Animals. 45 (2), 114-120 (2011).</li><li>Yang, 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=Safety+and+efficacy+of+a+modified+axillary+vein+technique+for+pacemaker+implantation.">Safety and efficacy of a modified axillary vein technique for pacemaker implantation.</a> Cardiology Plus. 3, 104-107 (2018).</li><li>Yang, 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=Subclavian+Vein+Puncture+As+an+Alternative+Method+of+Blood+Sample+Collection+in+Rats.">Subclavian Vein Puncture As an Alternative Method of Blood Sample Collection in Rats.</a> Journal of Visualized Experiments. (141), (2018).</li><li>Kilkenny, C., Altman, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improving+bioscience+research+reporting:+ARRIVE-ing+at+a+solution.">Improving bioscience research reporting: ARRIVE-ing at a solution.</a> Laboratory Animals. 44 (4), 377-378 (2010).</li><li>Research, I. f. L. 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> Guide for the care and use of laboratory animals. , (1996).</li><li>Redel, A., 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=Impact+of+ischemia+and+reperfusion+times+on+myocardial+infarct+size+in+mice+in+vivo.">Impact of ischemia and reperfusion times on myocardial infarct size in mice in vivo.</a> Experimental Biology and Medicine (Maywood, N.J.). 233 (1), 84-93 (2008).</li><li>Tsukamoto, A., Serizawa, K., Sato, R., Yamazaki, J., Inomata, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vital+signs+monitoring+during+injectable+and+inhalant+anesthesia+in+mice.">Vital signs monitoring during injectable and inhalant anesthesia in mice.</a> Experimental Animals. 64 (1), 57-64 (2015).</li><li>Zou, W., 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=Repeated+Blood+Collection+from+Tail+Vein+of+Non-Anesthetized+Rats+with+a+Vacuum+Blood+Collection+System.">Repeated Blood Collection from Tail Vein of Non-Anesthetized Rats with a Vacuum Blood Collection System.</a> Journal of Visualized Experiments. (130), (2017).</li></ol>

None declared.

This report represents an extension of previous research on blood sampling through the subclavian vein puncture in rats11. As the mouse is the most commonly used research animal, it would be valuable to see if this technique can also be applied to mice. The challenge comes from the relatively smaller diameter of the subclavian vein.
In the present research, we found that subclavian puncture in mice is a feasible and reliable way to collect blood. Compared to the conventional methods such as tail vein cutting or orbital blood collection, there are no ethical issues of the present method. All animals survived after this procedure without liquid supplements after around 200 &#181;L of blood extraction, and animals could be used for further experimental studies. Theoretically, the total sample volume extraction could not reach more than 10% of total circulating blood volume each time and the total volume of an adult animal is 55 to 70 mL/kg body weight5. For the mice used in this research (21.6-28.3 g), the maximum volume extraction should be around 200 &#181;L. We thus set the blood sampling amount around 200 &#181;L for each mouse. The inability to measure blood pressure, heart rate, and other stress parameters are the main limitations of this report.
Sufficient general anesthesia is another important issue to guarantee the success of the puncture. The mice should remain quiet during the puncture procedure to avoid the risk of injuring the vessel by the needle. We found that pentobarbital sodium at 60 mg/kg for general anesthesia could satisfy ideal depth of anesthesia. A downside of this agent is the relatively long recovery time (averaging about 30 minutes). In some institutes, isoflurane inhalation is used for the short recovery time and should be taken into consideration as an alternative anesthesia choice15.
The location of subclavian vein is shown in Figure 4. Because of the thin wall and low pressure in the vein, the anterior and posterior wall of the subclavian vein would attach to each other under the pressure of a needle while the needle is moving forward (Figure 5A). While withdrawing the plunger slowly backwards, the attached walls will separate spontaneously, and the tip of needle could enter the true cavity of vessel and blood could drain into the syringe under sustained negative pressure (Figure 5B). Use of a vacuum blood collection system16 might also favor the blood collection. Due to the relatively small diameter of the mice subclavian vein, there can be failures even for an experienced operator. For a novice, we recommend subclavian vein puncture in rats as reported11. After several successful puncture attempts in rats, the success rate of subclavian vein puncture in mice could be significantly enhanced. Make sure that the exact puncture location is just caudal to the middle of the clavicle bone. The needle moving upward and cranial to the superior sternal fossa are other key points to guarantee a successful puncture.
In conclusion, subclavian vein puncture is a safe and effective method for blood collection in mice. Besides tail vein cutting and retro-orbital plexus blood collection, this method is feasible, safe, and suitable for observational researches at several time points in mice.

Blood sample collection from mice is essential in most research laboratories. The conventional approaches for blood collection in mice is tail cutting when less than 100 &#181;L of sample is needed1. However, if more than 100 &#181;L of blood are required at a nonterminal time point, retroorbital, submandibular bleeding or submental blood collection are the most commonly considered techniques2. In some occasions, the jugular vein catheterization through a surgical incision was adopted as an alternative method3. 
Nevertheless, the above methods are harmful to the mice. To the best of our knowledge, the retroorbital method is not widely accepted because of the potential risk of complications4,5. Operation related trauma not only happens in the visible area6,7, but also deep within the orbit6. Besides, submandibular blood collection is stressful8 and might be associated with excessive bleeding2,9. Based on our prior research10,11, here we introduce a new strategy for blood collection from the subclavian vein in mice. The safety, feasibility, and obtained blood volume with this technique are presented and discussed.

<table border="0" cellpadding="0" cellspacing="0" style="width:1143px;" width="1144">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:374px;">1.0 mL syringe</td>
			<td style="width:576px;">Shandong Weigao Group Medical Polymer Co., Ltd (Weihai, Shandong Province, China)</td>
			<td style="width:130px;">20163151593</td>
			<td style="width:64px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">75% ethanol</td>
			<td>Department of Pharmacy, The Second Xiangya Hospital of Central South University</td>
			<td colspan="2">made in Department of Pharmacy,The Second Xiangya Hospital of Central South Univesity</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">adhesive tape</td>
			<td>3M Deutschland GmbH (Kamen, Germany)</td>
			<td>1534-1</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">canvas gloves</td>
			<td>for anesthesia</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">electronic scale</td>
			<td>Dongguan Shengheng Electronics Co. Ltd (Dongguan, Guangdong Province, China)</td>
			<td>KP-3000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">epilating agent</td>
			<td>France Yi Sha Cosmetics Co. Ltd (Guangzhou, Guangdong Province, China)</td>
			<td>8281744</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">heparin (used concentration 10 U/mL, 2 mL, 12500 IU)</td>
			<td>Nanjing Xinbai Pharmaceutical Co. Limited (Nanjing, Jiangsu Province, China)</td>
			<td>H32025851</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">mice</td>
			<td>Hunan SJA Laboratory Animal Co. Ltd (Changsha, Hunan Province, China)&#160;</td>
			<td>Kunming spcies</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">needle, 26G, 0.45 mm x 16 mm</td>
			<td>Shandong Weigao Group Medical Polymer Co. Ltd (Weihai, Shandong Province, China)</td>
			<td>20163151593</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">pentobarbital sodium (used solution 1%)</td>
			<td>Merck</td>
			<td>P-010-1ML</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">physiological saline, 100 mL</td>
			<td>Hunan Kelun Pharmaceutical Co. Ltd (Yueyang, Hunan Province,China)</td>
			<td>H43020454</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">stastical software</td>
			<td>International Business Machines</td>
			<td>SPSS Statistics 25</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">tube, 2 mL</td>
			<td>Hubei Jinxing Technology &#38; Development Co. Ltd (Wuhan Hubei Province, China)</td>
			<td>MCT-150-C</td>
			<td></td>
		</tr>
	</tbody>
</table>

blood collection through subclavian vein puncture in mice

The mouse is the foremost mammalian model for studying human disease and human health. However, blood sample collection from mice is challenging in research work. Tail blood collection is a popular method when a small amount of blood sample is needed. Orbital artery could be considered if a large amount of blood is needed but this blood collection method has ethical issues. Formerly, we demonstrated the feasibility and safety of blood sample collection through subclavian vein puncture in rats, and here we investigate whether this method could be used in mice. We report that this method is safe and practical for blood collection in mice. Blood collection through the subclavian vein puncture in mice can be a convenient method in daily research works.

We repeated this procedure in 10 Kunming mice (male n = 5, female n = 5, weight 25.4 &#177; 2.0 g). Nine procedures succeeded on the right side. One case failed within 3 attempts in the right side and blood collection succeeded on the left side. The time course (from puncture to obtaining required blood volume) ranged between 35-126 seconds (average 68.4 &#177; 26.4 s). Blood collection volume was set to around 200 &#181;L (average 203 &#177; 11.6 &#181;L). Blood collection succeeded within 1 to 4 attempts. Blood sampling succeeded on the first attempt in two mice and after 4 attempts in one mouse; the sampling took 2-3 attempts in the other mice. All data were illustrated in Table 1. All animals survived and recovered within 30 minutes after the blood sampling. There was no significant difference between sexes for all observed parameters (Table 1).
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/59556/59556fig1.jpg" /> 
Figure 1: General anesthesia through intraperitoneal injection <a href="https://www.jove.com/files/ftp_upload/59556/59556fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/59556/59556fig2.jpg" /> 
Figure 2: The supine position of mouse. Note the distance between margin and mouse is 2-4 cm. <a href="https://www.jove.com/files/ftp_upload/59556/59556fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/59556/59556fig3.jpg" /> 
Figure 3: The puncture site and posture of operator&#39;s hands. Note that the ring finger of right hand moves backward to form negative pressure. The left hand is placed lateral to the puncture site to fix the skin and subcutaneous tissues. <a href="https://www.jove.com/files/ftp_upload/59556/59556fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/59556/59556fig4.jpg" /> 
Figure 4: The location of the subclavian vein, clavicle bone and superior sternal fossa. The subclavian vein courses beneath the clavicle bone and drains into the superior vena cava under the superior sternal fossa. <a href="https://www.jove.com/files/ftp_upload/59556/59556fig4large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/59556/59556fig5.jpg" /> 
Figure 5: The relation between the vessel wall and needle during the procedure. (A) The walls of the subclavian vein attach to each other as the needle moves forward, so no blood could be drawn out. (B) While withdrawing the needle backward, the walls separate from each other and the blood could be drawn out. <a href="https://www.jove.com/files/ftp_upload/59556/59556fig5large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>variable</td>
			<td>Total (n=10)</td>
			<td>Male (n=5)</td>
			<td>Female (n=5)</td>
			<td>P Value</td>
		</tr>
		<tr>
			<td>Body Weight (g)</td>
			<td>25.3 &#177; 2.2</td>
			<td>25.3 &#177; 3.0</td>
			<td>25.4 &#177; 1.3</td>
			<td>0.926</td>
		</tr>
		<tr>
			<td>Blood Volume (&#956;L)</td>
			<td>203.0 &#177; 11.6</td>
			<td>208 &#177; 13.0</td>
			<td>198 &#177; 8.4</td>
			<td>0.187</td>
		</tr>
		<tr>
			<td>Time Course (s)</td>
			<td>68.4 &#177; 26.4</td>
			<td>70.6 &#177; 35.1</td>
			<td>66.2 &#177; 18.0</td>
			<td>0.809</td>
		</tr>
		<tr>
			<td>Withdrawals</td>
			<td>2.3 &#177; 0.9</td>
			<td>2.4 &#177; 1.1</td>
			<td>2.2 &#177; 0.8</td>
			<td>0.760</td>
		</tr>
		<tr>
			<td colspan="4">There were no significant sex differences for all observed parameters, all P value &#62;0.05.</td>
			<td></td>
		</tr>
	</tbody>
</table>
Table 1: Observed parameters between the sexes

Watch this Scientific Journal Video about Blood Collection Through Subclavian Vein Puncture in Mice at JoVE.com

Blood Collection Through Subclavian Vein Puncture in Mice

Here, we present a protocol to take blood samples from the subclavian vein of mice.

The mouse is the foremost mammalian model for studying human disease and human health. However, blood sample collection from mice is challenging in ...

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34.5K Views.  Central South University. Here, we present a protocol to take blood samples from the subclavian vein of mice.

Video: Blood Collection Through Subclavian Vein Puncture in Mice

Cecal Ligation Puncture Procedure

Human sepsis is characterized by a set of systemic reactions in response to intensive and massive infection that failed to be locally contained by the host. Currently, sepsis ranks among the top ten causes of mortality in the USA intensive care units 1. During sepsis there are two established haemodynamic phases that may overlap. The initial phase (hyperdynamic) is defined as a massive production of proinflammatory cytokines and reactive oxygen species by macrophages and neutrophils that affects vascular permeability (leading to hypotension), cardiac function and induces metabolic changes culminating in tissue necrosis and organ failure. Consequently, the most common cause of mortality is acute kidney injury. The second phase (hypodynamic) is an anti-inflammatory process involving altered monocyte antigen presentation, decreased lymphocyte proliferation and function and increased apoptosis. This state known as immunosuppression or immune depression sharply increases the risk of nocosomial infections and ultimately, death. The mechanisms of these pathophysiological processes are not well characterized. Because both phases of sepsis may cause irreversible and irreparable damage, it is essential to determine the immunological and physiological status of the patient. This is the main reason why many therapeutic drugs have failed. The same drug given at different stages of sepsis may be therapeutic or otherwise harmful or have no effect 2,3. To understand sepsis at various levels it is crucial to have a suitable and comprehensive animal model that reproduces the clinical course of the disease. It is important to characterize the pathophysiological mechanisms occurring during sepsis and control the model conditions for testing potential therapeutic agents. 
To study the etiology of human sepsis researchers have developed different animal models. The most widely used clinical model is cecal ligation and puncture (CLP). The CLP model consists of the perforation of the cecum allowing the release of fecal material into the peritoneal cavity to generate an exacerbated immune response induced by polymicrobial infection. This model fulfills the human condition that is clinically relevant. As in humans, mice that undergo CLP with fluid resuscitation show the first (early) hyperdynamic phase that in time progresses to the second (late) hypodynamic phase. In addition, the cytokine profile is similar to that seen in human sepsis where there is increased lymphocyte apoptosis (reviewed in 4,5). Due to the multiple and overlapping mechanisms involved in sepsis, researchers need a suitable sepsis model of controlled severity in order to obtain consistent and reproducible results.

The mouse model of cecal ligation and puncture as a valuable tool for the study of human sepsis.

Human sepsis is characterized by a set of systemic reactions in response to intensive and massive infection that failed to be locally contained by the ...

Delivery of Therapeutic Agents Through Intracerebroventricular (ICV) and Intravenous (IV) Injection in Mice

Despite the protective role that blood brain barrier plays in shielding the brain, it limits the access to the central nervous system (CNS) which most often results in failure of potential therapeutics designed for neurodegenerative disorders 1,2. Neurodegenerative diseases such as Spinal Muscular Atrophy (SMA), in which the lower motor neurons are affected, can benefit greatly from introducing the therapeutic agents into the CNS. The purpose of this video is to demonstrate two different injection paradigms to deliver therapeutic materials into neonatal mice soon after birth. One of these methods is injecting directly into cerebral lateral ventricles (Intracerebroventricular) which results in delivery of materials into the CNS through the cerebrospinal fluid 3,4. The second method is a temporal vein injection (intravenous) that can introduce different therapeutics into the circulatory system, leading to systemic delivery including the CNS 5. Widespread transduction of the CNS is achievable if an appropriate viral vector and viral serotype is utilized. Visualization and utilization of the temporal vein for injection is feasible up to postnatal day 6. However, if the delivered material is intended to reach the CNS, these injections should take place while the blood brain barrier is more permeable due to its immature status, preferably prior to postnatal day 2. The fully developed blood brain barrier greatly limits the effectiveness of intravenous delivery. Both delivery systems are simple and effective once the surgical aptitude is achieved. They do not require any extensive surgical devices and can be performed by a single person. However, these techniques are not without challenges. The small size of postnatal day 2 pups and the subsequent small target areas can make the injections difficult to perform and initially challenging to replicate.

Delivery of Therapeutic Agents Through Intracerebroventricular ICV and Intravenous IV Injection in Mice

This article demonstrates two very different methods of injection: 1) into the brain (intracerebroventricular) and 2) systemic (intravenous) to introduce the therapeutic agents into the central nervous system of neonatal mice.

Despite the protective role that blood brain barrier plays in shielding the brain, it limits the access to the central nervous system (CNS) which most ...

Dried Blood Spot Collection of Health Biomarkers to Maximize Participation in Population Studies

Biomarkers are directly-measured biological indicators of disease, health, exposures, or other biological information. In population and social sciences, biomarkers need to be easy to obtain, transport, and analyze. Dried Blood Spots meet this need, and can be collected in the field with high response rates. These elements are particularly important in longitudinal study designs including interventions where attrition is critical to avoid, and high response rates improve the interpretation of results. Dried Blood Spot sample collection is simple, quick, relatively painless, less invasive then venipuncture, and requires minimal field storage requirements (i.e.&#160;samples do not need to be immediately frozen and can be stored for a long period of time in a stable freezer environment before assay). The samples can be analyzed for a variety of different analytes, including cholesterol, C-reactive protein, glycosylated hemoglobin, numerous cytokines, and other analytes, as well as provide genetic material. DBS collection is depicted as employed in several recent studies.

Biomarkers are directly-measured biological indicators of disease or health. In population and social sciences, biomarkers need to be easy to obtain, transport, and analyze. Dried Blood Spot (DBS) collection meets this need, can be collected in the field with high response rates&#160;and analyzed for a variety of biomarkers.

Biomarkers are directly-measured biological indicators of disease, health, exposures, or other biological information. In population and social sciences, ...

Intravital Video Microscopy Measurements of Retinal Blood Flow in Mice

Alterations in retinal blood flow can contribute to, or be a consequence of, ocular disease and visual dysfunction. Therefore, quantitation of altered perfusion can aid research into the mechanisms of retinal pathologies. Intravital video microscopy of fluorescent tracers can be used to measure vascular diameters and bloodstream velocities of the retinal vasculature, specifically the arterioles branching from the central retinal artery and of the venules leading into the central retinal vein. Blood flow rates can be calculated from the diameters and velocities, with the summation of arteriolar flow, and separately venular flow, providing values of total retinal blood flow. This paper and associated video describe the methods for applying this technique to mice, which includes 1) the preparation of the eye for intravital microscopy of the anesthetized animal, 2) the intravenous infusion of fluorescent microspheres to measure bloodstream velocity, 3) the intravenous infusion of a high molecular weight fluorescent dextran, to aid the microscopic visualization of the retinal microvasculature, 4) the use of a digital microscope camera to obtain videos of the perfused retina, and 5) the use of image processing software to analyze the video. The same techniques can be used for measuring retinal blood flow rates in rats.

Intravital microscopy can be used in animals to visualize and measure retinal vascular diameters, bloodstream velocities, and total retinal blood flow.

Alterations in retinal blood flow can contribute to, or be a consequence of, ocular disease and visual dysfunction. Therefore, quantitation of altered ...

Long-term Blood Pressure Measurement in Freely Moving Mice Using Telemetry

During the development of new vasoactive agents, arterial blood pressure monitoring is crucial for evaluating the efficacy of the new proposed drugs. Indeed, research focusing on the discovery of new potential therapeutic targets using genetically altered mice requires a reliable, long-term assessment of the systemic arterial pressure variation. Currently, the gold standard for obtaining long-term measurements of blood pressure in ambulatory mice uses implantable radio-transmitters, which require&#160;artery cannulation. This technique eliminates the need for tethering, restraining, or anesthetizing the animals which introduce stress and artifacts during data sampling. However, arterial blood pressure monitoring in mice via catheterization can be rather challenging due to the small size of the arteries. Here we present a step-by-step guide to illustrate the crucial key passages for a successful subcutaneous implantation of radio-transmitters and carotid artery cannulation in mice. We also include examples of long-term blood pressure activity taken from freely moving mice after a period of post-surgery recovery. Following this procedure will allow reliable direct blood pressure recordings from multiple animals simultaneously.

The goal of this protocol is to assess systemic blood pressure in conscious freely moving mice using implantable radio-telemetry devices.

During the development of new vasoactive agents, arterial blood pressure monitoring is crucial for evaluating the efficacy of the new proposed drugs. ...

Repeated Blood Collection from Tail Vein of Non-Anesthetized Rats with a Vacuum Blood Collection System

Blood can be collected from rats in a number of sampling locations. For instance, the tail vein is a superior location for blood sampling. However, the tail vein is thin so that it is sometimes hard to puncture. In addition, the tail vein has low blood flow and requires a long sampling time to get sufficient blood. The present report describes a simple blood sampling method, the vacuum blood collection method, which is usually used to obtain blood samples from patients, here used for non-anesthetized rats. The 22 G butterfly needle tip was inserted into one of the lateral tail veins approximately 2-3 cm from the tip of the tail at an angle of approximately 20&#176;, and blood was collected in the vacuum collection tube by inserting the rubber end of the butterfly needle into the vacuum blood collection tube. The present experimental results show that the success rate was 95% in the experimental group and 90% in the beginner group. The success rate and puncture times were similar between two groups. The sampling duration was significantly shorter in the experimental group compared to beginner group. In conclusion, this vacuum blood collection method for sequential blood sampling from the tail vein of non- anesthetized rats is feasible and easy-to-learn, which might serve as a reliable alternative to other conventionally used blood sampling techniques for rats.

Here, we describe a simple tail vein blood sampling method in non-anesthetized rats using a vacuum extraction tube system. This method reduces the risk of direct exposure to blood and simplifies taking multiple samples from a single venipuncture.

Blood can be collected from rats in a number of sampling locations. For instance, the tail vein is a superior location for blood sampling. However, the ...

Subclavian Vein Puncture As an Alternative Method of Blood Sample Collection in Rats

Blood collection with enough blood volume is essential in animal experiments. Blood collection from the tail vein of rats is popular and less stressful compared to other more aggressive methods such as retro-orbital plexus sample collection. However, this blood collection method is sometimes limited by an unsatisfactory success rate. Here, we introduce a method for blood collection through the subclavian vein puncture. The subclavian vein is located just under the clavicle and this vein is large enough to fulfill the volume requirements of blood collection. Our results show that this method is safe and applicable for blood collection sampling with the required blood volume. Blood collection through the subclavian vein puncture could serve as an alternative blood collection method in case of failed tail vein blood sampling in rats.

Here, we present a protocol to collect blood samples from the rat subclavian vein.

Blood collection with enough blood volume is essential in animal experiments. Blood collection from the tail vein of rats is popular and less stressful ...

Quantitative Analysis of Cellular Composition in Advanced Atherosclerotic Lesions of Smooth Muscle Cell Lineage-Tracing Mice

Atherosclerosis remains the leading cause of death worldwide and, despite countless preclinical studies describing promising therapeutic targets, novel interventions have remained elusive. This is likely due, in part, to a reliance on preclinical prevention models investigating the effects of genetic manipulations or pharmacological treatments on atherosclerosis development rather than the established disease. Also, results of these studies are often confounding because of the use of superficial lesion analyses and a lack of characterization of lesion cell populations. To help overcome these translational hurdles, we propose an increased reliance on intervention models that employ investigation of changes in cellular composition at a single cell level by immunofluorescent staining and confocal microscopy. To this end, we describe a protocol for testing a putative therapeutic agent in a murine intervention model including a systematic approach for animal dissection, embedding, sectioning, staining, and quantification of brachiocephalic artery lesions. In addition, due to the phenotypic diversity of cells within late-stage atherosclerotic lesions, we describe the importance of using cell-specific, inducible lineage tracing mouse systems and how this can be leveraged for unbiased characterization of atherosclerotic lesion cell populations. Together, these strategies may assist vascular biologists to more accurately model therapeutic interventions and analyze atherosclerotic disease and will hopefully translate into a higher rate of success in clinical trials.

We propose a standardized protocol to characterize the cellular composition of late-stage murine atherosclerotic lesions including systematic methods of animal dissection, tissue embedding, sectioning, staining, and analysis of brachiocephalic arteries from atheroprone smooth muscle cell lineage tracing mice.

Atherosclerosis remains the leading cause of death worldwide and, despite countless preclinical studies describing promising therapeutic targets, novel ...

Simultaneous Flow Cytometric Characterization of Multiple Cell Types Retrieved from Mouse Brain/Spinal Cord Through Different Homogenization Methods

Recent advances in viral vector and nanomaterial sciences have opened the way for new cutting-edge approaches to investigate or manipulate the central nervous system (CNS). However, further optimization of these technologies would benefit from methods allowing rapid and streamline determination of the extent of CNS and cell-specific targeting upon administration of viral vectors or nanoparticles in the body. Here, we present a protocol that takes advantage of the high throughput and multiplexing capabilities of flow cytometry to allow a straightforward quantification of different cell subtypes isolated from mouse brain or spinal cord, namely microglia/macrophages, lymphocytes, astrocytes, oligodendrocytes, neurons and endothelial cells. We apply this approach to highlight critical differences between two tissue homogenization methods in terms of cell yield, viability and composition. This could instruct the user to choose the best method depending on the cell type(s) of interest and the specific application. This method is not suited for analysis of anatomical distribution, since the tissue is homogenized to generate a single-cell suspension. However, it allows to work with viable cells and it can be combined with cell-sorting, opening the way for several applications that could expand the repertoire of tools in the hands of the neuroscientist, ranging from establishment of primary cultures derived from pure cell populations, to gene-expression analyses and biochemical or functional assays on well-defined cell subtypes in the context of neurodegenerative diseases, upon pharmacological treatment or gene therapy.

We present a flow cytometry method to identify simultaneously different cell types retrieved from mouse brain or spinal cord. This method could be exploited to isolate or characterize pure cell populations in neurodegenerative diseases or to quantify the extent of cell targeting upon in vivo administration of viral vectors or nanoparticles.

Recent advances in viral vector and nanomaterial sciences have opened the way for new cutting-edge approaches to investigate or manipulate the central ...

Minimizing Post-Infusion Portal Vein Bleeding during Intrahepatic Islet Transplantation in Mice

Although the liver is currently accepted as the primary transplantation site for human islets in clinical settings, islets are transplanted under the kidney capsule in most rodent preclinical islet transplantation studies. This model is commonly used because murine intrahepatic islet transplantation is technically challenging, and a high percentage of mice could die from surgical complications, especially bleeding from the injection site post-transplantation. In this study, two procedures that can minimize the incidence of post-infusion portal vein bleeding are demonstrated. The first method applies an absorbable hemostatic gelatin sponge to the injection site, and the second method involves penetrating the islet injection needle through the fat tissue first and then into the portal vein by using the fat tissue as a physical barrier to stop bleeding. Both methods could effectively prevent bleeding-induced mouse death. The whole liver section showing islet distribution and evidence of islet thrombosis post-transplantation, a typical feature for intrahepatic islet transplantation, were presented. These improved protocols refine the intrahepatic islet transplantation procedures and may help laboratories set up the procedure to study islet survival and function in pre-clinical settings.

Here we present refined surgical procedures on successfully performing intraportal islet transplantation, a clinically relevant but technically challenging surgical procedure, in mice.

Although the liver is currently accepted as the primary transplantation site for human islets in clinical settings, islets are transplanted under the ...