The authors wish to thank Andy Poczobutt and Dr. Jori Leszczynski for their valuable help and edits to this manuscript.&#160;Supported by Grants received from the National Heart, Lung and Blood Institute (NHLBI RO1 HL078929, PPG HL014985 and RO3 HL095439) and the Department of Veterans&#39; Affairs (Merit Review).

All applicable international, national, and/or institutional guidelines for the care and use of animals (mice) were followed in the experiments described in this manuscript.
This method uses FVBN adult mice, aged 16 - 20 weeks, found to be optimal for the purposes of this study. Day 1 includes steps 1 - 5 and Day 2 includes steps 6 - 7 (Figure 1).
1. Equipment Preparation
<ol>
	<li>Secure an adequate supply of sterile, disposable syri...

<ol>
	<li>Snijdelaar, D. G., Dirksen, R., Slappendel, R., Crul, B. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Substance+P.">Substance P.</a> Eur J Pain. 4 (2), 121-135 (2000).</li><li>Rubinstein, I., Iwamoto, I., Ueki, I. F., Borson, D. B., Nadel, 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=Recombinant+neutral+endopeptidase+attenuates+substance+P-induced+plasma+extravasation+in+the+guinea+pig+skin.">Recombinant neutral endopeptidase attenuates substance P-induced plasma extravasation in the guinea pig skin.</a> Int Arch Allergy Appl Immunol. 91 (3), 232-238 (1990).</li><li>Szabo, A., Menger, M. D., Boros, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microvascular+and+epithelial+permeability+measurements+in+laboratory+animals.">Microvascular and epithelial permeability measurements in laboratory animals.</a> Microsurgery. 26 (1), 50-53 (2006).</li><li>Radu, M., Chernoff, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+in+vivo+assay+to+test+blood+vessel+permeability.">An in vivo assay to test blood vessel permeability.</a> J Vis Exp. (73), e50062 (2013).</li><li>Moitra, J., Sammani, S., Garcia, J. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Re-evaluation+of+Evans+Blue+dye+as+a+marker+of+albumin+clearance+in+murine+models+of+acute+lung+injury.">Re-evaluation of Evans Blue dye as a marker of albumin clearance in murine models of acute lung injury.</a> Transl Res. 150 (4), 253-265 (2007).</li><li>Figini, 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=Substance+P+and+bradykinin+stimulate+plasma+extravasation+in+the+mouse+gastrointestinal+tract+and+pancreas.">Substance P and bradykinin stimulate plasma extravasation in the mouse gastrointestinal tract and pancreas.</a> Am J Physiol. 272 (4), 785-793 (1997).</li><li>Awad, A. 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=Selective+sphingosine+1-phosphate+1+receptor+activation+reduces+ischemia-reperfusion+injury+in+mouse+kidney.">Selective sphingosine 1-phosphate 1 receptor activation reduces ischemia-reperfusion injury in mouse kidney.</a> Am J Physiol Renal Physiol. 290 (6), 1516-1524 (2006).</li><li>Lu, B., 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=The+control+of+microvascular+permeability+and+blood+pressure+by+neutral+endopeptidase.">The control of microvascular permeability and blood pressure by neutral endopeptidase.</a> Nat Med. 3 (8), 904-907 (1997).</li><li>Gendron, G., Simard, B., Gobeil, F., Sirois, P., D'Orleans-Juste, P., Regoli, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+urotensin-II+enhances+plasma+extravasation+in+specific+vascular+districts+in+Wistar+rats.">Human urotensin-II enhances plasma extravasation in specific vascular districts in Wistar rats.</a> Can J Physiol Pharmacol. 82 (1), 16-21 (2004).</li><li>Xu, Q., Qaum, T., Adamis, A. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sensitive+blood-retinal+barrier+breakdown+quantitation+using+Evans+blue.">Sensitive blood-retinal barrier breakdown quantitation using Evans blue.</a> Invest Ophthalmol Vis Sci. 42 (3), 789-794 (2001).</li><li>Saria, A., Lundberg, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evans+blue+fluorescence:+quantitative+and+morphological+evaluation+of+vascular+permeability+in+animal+tissues.">Evans blue fluorescence: quantitative and morphological evaluation of vascular permeability in animal tissues.</a> J Neurosci Methods. 8 (1), 41-49 (1983).</li><li>Fricke, I. B., 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=In+vivo+bioluminescence+imaging+of+neurogenesis+-+the+role+of+the+blood+brain+barrier+in+an+experimental+model+of+Parkinson's+disease.">In vivo bioluminescence imaging of neurogenesis - the role of the blood brain barrier in an experimental model of Parkinson's disease.</a> Eur J Neurosci. 45 (7), 975-986 (2017).</li><li>Pink, D. B., Schulte, W., Parseghian, M. H., Zijlstra, A., Lewis, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Real-time+visualization+and+quantitation+of+vascular+permeability+in+vivo:+implications+for+drug+delivery.">Real-time visualization and quantitation of vascular permeability in vivo: implications for drug delivery.</a> PLoS One. 7 (3), 33760 (2012).</li><li>Jain, R. K., Munn, L. L., Fukumura, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dissecting+tumour+pathophysiology+using+intravital+microscopy.">Dissecting tumour pathophysiology using intravital microscopy.</a> Nat Rev Cancer. 2 (4), 266-276 (2002).</li><li>Vandoorne, K., Addadi, Y., Neeman, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visualizing+vascular+permeability+and+lymphatic+drainage+using+labeled+serum+albumin.">Visualizing vascular permeability and lymphatic drainage using labeled serum albumin.</a> Angiogenesis. 13 (2), 75-85 (2010).</li><li>Turner, A. J., Nalivaeva, N. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Proteinase+dysbalance+in+pathology:+the+neprilysin+(NEP)+and+angiotensin-converting+enzyme+(ACE)+families.">Proteinase dysbalance in pathology: the neprilysin (NEP) and angiotensin-converting enzyme (ACE) families.</a> Cell Mol Biol (Noisy-le-grand). 52 (4), 40-48 (2006).</li><li>Lu, B., Gerard, N. P., Kolakowski, L. F., Finco, O., Carroll, M. C., Gerard, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neutral+endopeptidase+modulates+septic+shock.">Neutral endopeptidase modulates septic shock.</a> Ann N Y Acad Sci. 780, 156-163 (1996).</li><li>Dempsey, E. C., 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=Neprilysin+null+mice+develop+exaggerated+pulmonary+vascular+remodeling+in+response+to+chronic+hypoxia.">Neprilysin null mice develop exaggerated pulmonary vascular remodeling in response to chronic hypoxia.</a> Am J Pathol. 174 (3), 782-796 (2009).</li><li>Karoor, V., Oka, M., Walchak, S. J., Hersh, L. B., Miller, Y. E., Dempsey, E. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neprilysin+regulates+pulmonary+artery+smooth+muscle+cell+phenotype+through+a+platelet-derived+growth+factor+receptor-dependent+mechanism.">Neprilysin regulates pulmonary artery smooth muscle cell phenotype through a platelet-derived growth factor receptor-dependent mechanism.</a> Hypertension. 61 (4), 921-930 (2013).</li><li>Chu, P., Arber, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Paraffin-section+detection+of+CD10+in+505+nonhematopoietic+neoplasms.+Frequent+expression+in+renal+cell+carcinoma+and+endometrial+stromal+sarcoma.">Paraffin-section detection of CD10 in 505 nonhematopoietic neoplasms. Frequent expression in renal cell carcinoma and endometrial stromal sarcoma.</a> Am J Clin Pathol. 113 (3), 374-382 (2000).</li><li>Bircan, S., Candir, O., Kapucuoglu, N., Serel, T. A., Ciris, M., Karahan, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CD10+expression+in+urothelial+bladder+carcinomas:+a+pilot+study.">CD10 expression in urothelial bladder carcinomas: a pilot study.</a> Urol Int. 77 (2), 107-113 (2006).</li><li>Koiso, K., Akaza, H., Ohtani, M., Miyanaga, N., Aoyagi, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+tumor+marker+for+bladder+cancer.">A new tumor marker for bladder cancer.</a> Int J Urol. 1 (1), 33-36 (1994).</li><li>Wick, M. J., 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=Protection+against+vascular+leak+in+neprilysin+transgenic+mice+with+complex+overexpression+pattern.">Protection against vascular leak in neprilysin transgenic mice with complex overexpression pattern.</a> Transgenic Res. 25 (6), 773-784 (2016).</li><li>Natah, S. S., Srinivasan, S., Pittman, Q., Zhao, Z., Dunn, J. F. <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+acute+hypoxia+and+hyperthermia+on+the+permeability+of+the+blood-brain+barrier+in+adult+rats.">Effects of acute hypoxia and hyperthermia on the permeability of the blood-brain barrier in adult rats.</a> J Appl Physiol. 107 (4), 1348-1356 (2009).</li><li>Scholzen, T. 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=Neutral+endopeptidase+terminates+substance+P-induced+inflammation+in+allergic+contact+dermatitis.">Neutral endopeptidase terminates substance P-induced inflammation in allergic contact dermatitis.</a> J Immunol. 166 (2), 1285-1291 (2001).</li></ol>

The authors have nothing to disclose.

As discussed above, the study of plasma extravasation may ultimately lead to new knowledge concerning the causes of or new ways to inhibit or treat plasma extravasation. The successful use of the plasma extravasation protocol (above), using Evans blue dye, has been demonstrated in the current manuscript. Although the data shown back the hypothesis that NEP may protect the vasculature against plasma extravasation, this is a secondary goal presently, with the primary goal being to present an optimized protocol which may be...

Vascular leak in the organs refers to extravasation, or leakage of blood plasma through gaps produced in the endothelium of post capillary venules in the organs. This plasma extravasation or increased vascular permeability, which may arise from some type of an inflammatory response, may have grave consequences. Thus, it is important that this phenomenon, its causes, modulators, and consequences, are studied and understood, and likewise, that investigators have good tools and protocols with which to study them. The endothelial gaps may be produced via a number of stimuli, but usually are produced by the action of peptide neurotransmitters and/or tachykinins on the endothelia. One of the major naturally occurring mediators of this process, which results in increased plasma extravasation, is the undecapeptide tachykinin neuropeptide, substance P1.
Methods to investigate and measure vascular permeability or plasma extravasation, which use the albumin-binding property of Evans blue dye, have been developed, and are usually known for their accuracy, simplicity, economy, safety, and ability to allow the determination of plasma extravasation from several tissues at once, if so desired2,3,4,5,6,7,8,9. This Evans blue protocol for assessing plasma extravasation in the organs of FVBN mice uses all these, but adds some important modifications that make it generally useful and adaptable for future studies, involving the average laboratory that conducts or will conduct important studies of factors associated with plasma extravasation or vascular permeability. In this protocol, substance P is introduced to the mice at 1 nmol/kg, which augments the extravasation of plasma by 1.5-fold. This increases the sensitivity of the protocol, resulting in more easily observable and obtainable results. Other factors that impact permeability, such as various other peptides, chemicals, or some forms of toxic injury, may be used or studied by other laboratories, as desired. Jugular vein injections are used in this protocol to introduce Evans blue and substance P systemically, which requires terminal surgery. However, jugular vein injections5,7,10, even after consideration of the necessary terminal surgical techniques, are easier to master and lead to the production of more consistent results than other venous injections, including tail vein injections4,9. Although it may be possible for Evans blue to be delivered by retro-orbital venous sinus injections, no references in the literature have been found that use this method of delivery of Evans blue. However, as for tail vein injections, the high degree of expertise and practice to reproducibly master this technique greatly limits its use for successful Evans blue injections. In contrast, the alternative jugular vein injection method as described in our protocol, offers a technically obtainable solution. A crucial procedure for perfusion of the mouse&#39;s veins, performed just after the sacrifice of the Evans blue-perfused mouse, removes excess Evans blue dye, and has been standardized in this protocol. Previously described methods of perfusion have been carefully examined and modified to obtain the present procedure.Other modifications described here are all optimized, straightforward, and inexpensive.
There are some important limitations of the Evans blue dye method. For example, low sensitivity sometimes associated with this method may prevent some additional gross pathological and histological examination of tissues from Evans blue-injected animals. However, these and other limitations have led to the development of alternative methods and models that, nonetheless, still use Evans blue. The measurement of Evans blue by fluorescence (rather than by visual-range) spectroscopy may increase the sensitivity of the method. Additionally, fluorescence microscopy of Evans blue-stained tissues was developed to allow for observation of vascular leak in more distinct locations11. Also, whole-body imaging and scanning of a live animal previously injected with Evans blue12&#160;allows for investigation of Evans blue concentrations in a continuous manner, rather than at one specific chosen time point of the experiment. However, this method requires the availability of appropriate imaging facilities, and may be very expensive. Modifications involving Evans blue and performed in an in vitro type of model, such as in a cell culture or chick chorioallantoic model13 (CAM) have also been described. These models are monitored by fluorescence and intravital14&#160;microscopy, and allow the quantification of vascular permeability changes over time, but may raise questions regarding accurate modeling of in vivo conditions and may also be expensive.
There have been other methods developed to determine and quantify vascular leak or permeability, which do not involve the administration of Evans blue. These methods may employ an appropriate fluorescent molecule (such as albumin or fluorescein), or an isotopically labeled or otherwise tagged molecule, to live animals (or to cell culture or chorioallantoic (CAM) models13, followed by non-invasive imaging (PET scanning, MRI, intravital microscopy, whole body scanning) or by invasive imaging (fluorescent microscopy)3,12,15. Although these techniques may offer a number of advantages over other Evans blue methods, they also have disadvantages, which may include their considerable complexities, requisite expertise, resources, and high monetary costs.
Neprilysin16 (the peptidase enzyme NEP, also known as CD10, MME, or Enkephalinase) has been suggested to be involved in inhibiting plasma extravasation, at least in part, through the enzymatic metabolism and inactivation of endogenous substance P. Thus, in tissues in which the cell surface peptidase NEP occurs, there may be an attenuation of the effect of substance P, presumably by the peptidase activity of NEP.
Initially, we tested for substance P-induced plasma extravasation utilizing this modified Evans blue protocol, with FVBN wild type (WT) and NEP knockout (KO) mice. NEP involvement in substance P-augmented plasma extravasation was suspected from these initial studies, and we describe these and further experiments involving NEP&#39;s role in plasma extravasation. However, the focus of this manuscript is not NEP or its role in plasma extravasation, but rather the plasma extravasation experiments themselves. The NEP results are representative of the kind of results that may be obtained through use of this modified protocol. The Evans blue method to measure plasma extravasation has been optimized and modified, as described in detail below for FVBN mice.

<table border="0" cellpadding="0" cellspacing="0" style="width:687px;" width="686">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">isoflurane</td>
			<td style="width:167px;">Vet One</td>
			<td style="width:119px;">200-070</td>
			<td style="width:185px;">inhaled anesthetic</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">ketamine</td>
			<td style="width:167px;">Vet One</td>
			<td style="width:119px;">200-055</td>
			<td>injectable anesthetic</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">xylazine</td>
			<td style="width:167px;">Lloyd Laboratories</td>
			<td style="width:119px;">139-236</td>
			<td>injectable anesthetic</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">syringes (10,3 &#38; 1 cc)</td>
			<td style="width:167px;">Becton Dickinson</td>
			<td style="width:119px;">309604, 309657, 309659</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">needles (20G1,23G1 &#38; 26G1/2)</td>
			<td style="width:167px;">Becton Dickinson</td>
			<td style="width:119px;">305178, 305193, 305111</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">isoflurane induction chamber</td>
			<td style="width:167px;">VetEquip</td>
			<td style="width:119px;">941443</td>
			<td>1 Liter</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">nosecone breathing circuits&#160;</td>
			<td style="width:167px;">VetEquip</td>
			<td style="width:119px;">RC2</td>
			<td>Rodent Circuit Controller 2</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">oxygen tank</td>
			<td style="width:167px;">Airgas</td>
			<td style="width:119px;">UN 1072</td>
			<td>100% medical</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">heating pad</td>
			<td style="width:167px;">CWE Inc.</td>
			<td style="width:119px;">TC-1000</td>
			<td>temperature controller</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">rectal temperature probe</td>
			<td style="width:167px;">CWE Inc.</td>
			<td>10-09012</td>
			<td>mouse</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">balance (for rodents)</td>
			<td style="width:167px;">Ohaus</td>
			<td style="width:119px;">CS 2000</td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">surgical tools-scissors</td>
			<td style="width:167px;">Fine Science tools</td>
			<td>15000-00</td>
			<td style="width:185px;">Vannas Spring scissors 3mm straight blade (cutting vessels)&#160;&#160;</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">surgical tools-forceps</td>
			<td style="width:167px;">Fine Science tools</td>
			<td>11151-10</td>
			<td style="width:185px;">Graefe extra fine forceps (isolating mouse vessels)</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">surgical tools-hemostats</td>
			<td style="width:167px;">Fine Science tools</td>
			<td>13009-12</td>
			<td style="width:185px;">Halstead-mosquito hemostats (blunt dissect, hold tissue)</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">surgical tools -suture drivers</td>
			<td style="width:167px;">Fine Science tools</td>
			<td>12502-12</td>
			<td style="width:185px;">Olsen-Hegar suture drivers (suturing)</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">surgical tools-forceps</td>
			<td style="width:167px;">Fine Science tools</td>
			<td>11627-12</td>
			<td style="width:185px;">Adson-Brown alligator forceps (tissue grasping suturing, rat)</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">surgical tools-scissors</td>
			<td style="width:167px;">Fine Science tools</td>
			<td>14110-15</td>
			<td style="width:185px;">Mayo tough cut scissors 15 cm (surgery, dissection, bones, rat)</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">surgical tools-forceps</td>
			<td style="width:167px;">Fine Science tools</td>
			<td>18025-10</td>
			<td style="width:185px;">suture tying forceps (used for Millar cath)</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">surgical tools-scissors</td>
			<td style="width:167px;">Fine Science tools</td>
			<td>14078-10</td>
			<td style="width:185px;">Lexer Baby scissors straight (surgery, mouse)</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">surgical tools-forceps</td>
			<td style="width:167px;">Fine Science tools</td>
			<td>11254-20</td>
			<td style="width:185px;">Dumont #5 fine-tip forceps (rat vessels, dissection)</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">surgical tools-scissors</td>
			<td style="width:167px;">Fine Science tools</td>
			<td>14082-09</td>
			<td style="width:185px;">Dissector scissors 12 mm (surgery, rat mouse)</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">surgical tools-forceps</td>
			<td style="width:167px;">Fine Science tools</td>
			<td>11051-10</td>
			<td style="width:185px;">10 cm Graefe forceps (tissue grasping, rat mouse)</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">surgical tools-forceps</td>
			<td style="width:167px;">Fine Science tools</td>
			<td>11251-35</td>
			<td style="width:185px;">Dumont 5/45 forceps (introducer for vessels)</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">surgical tools-retractors</td>
			<td style="width:167px;">Fine Science tools</td>
			<td>17012-11</td>
			<td style="width:185px;">Weitlaner retractors 2/3 tooth (rat surgical)</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">surgical tools-forceps</td>
			<td style="width:167px;">Fine Science tools</td>
			<td>11294-00</td>
			<td style="width:185px;">Dumont #4 forceps (vessel isolation rats, mice)</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">surgical tools-forceps</td>
			<td style="width:167px;">Fine Science tools</td>
			<td>11297-00</td>
			<td style="width:185px;">Dumont #7 forceps (tissue grasping, dissection)</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">surgical tools-scissors</td>
			<td style="width:167px;">Fine Science tools</td>
			<td>14058-11</td>
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			<td style="width:167px;">Fine Science tools</td>
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			<td height="42" style="height:42px;width:216px;">surgical tools-forceps</td>
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			<td height="21" style="height:21px;width:216px;">clippers</td>
			<td style="width:167px;">Oster</td>
			<td style="width:119px;">A5</td>
			<td></td>
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		<tr height="21">
			<td height="21" style="height:21px;width:216px;">tape</td>
			<td style="width:167px;">Fisherbrand</td>
			<td style="width:119px;">159015G</td>
			<td></td>
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		<tr height="21">
			<td height="21" style="height:21px;width:216px;">artificial tear ointment</td>
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		<tr height="21">
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			<td>2% injectable</td>
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		<tr height="21">
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			<td style="width:167px;">Tygon</td>
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			<td></td>
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		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Evans blue</td>
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			<td style="width:119px;">E2129</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Substance P</td>
			<td style="width:167px;">Bachem&#160;</td>
			<td style="width:119px;">H-1890</td>
			<td></td>
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		<tr height="21">
			<td height="21" style="height:21px;width:216px;">heparin</td>
			<td style="width:167px;">Sagent Pharmaceuticals</td>
			<td style="width:119px;">25201-400-10</td>
			<td>1000 U/ml</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:216px;">saline solution</td>
			<td style="width:167px;">Hospira</td>
			<td style="width:119px;">0409-7138-09</td>
			<td>0.9% sodium chloride</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:216px;">phenobarbital&#160;</td>
			<td style="width:167px;">Vortech</td>
			<td style="width:119px;">0298-9373-68</td>
			<td></td>
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		<tr height="21">
			<td height="21" style="height:21px;width:216px;">sodium citrate</td>
			<td style="width:167px;">Fisher Scientific</td>
			<td style="width:119px;">BP327-1</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">PBS</td>
			<td style="width:167px;">Sigma Aldrich</td>
			<td style="width:119px;">P4417-50TAB&#160;</td>
			<td></td>
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		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Kimwipes for blotting</td>
			<td style="width:167px;">Fisher Scientific</td>
			<td style="width:119px;">06-666A</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">formamide</td>
			<td style="width:167px;">Sigma Aldrich</td>
			<td style="width:119px;">47670</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">microbalance</td>
			<td style="width:167px;">Denver Instrument</td>
			<td style="width:119px;">APX-60</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">microfuge tubes</td>
			<td style="width:167px;">Fisher Scientific</td>
			<td style="width:119px;">07-200-534</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">polystyrene 96 well plate</td>
			<td style="width:167px;">Becton Dickenson</td>
			<td style="width:119px;">351172</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">absorbance plate reader</td>
			<td style="width:167px;">BioTek</td>
			<td style="width:119px;">Synergy 2</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">polyacrylamide gels</td>
			<td style="width:167px;">Bio-Rad</td>
			<td>3450014&#160;</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">protein molecular weight standard</td>
			<td style="width:167px;">Bio-Rad</td>
			<td>1610374</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Protran supported nitrocellulose</td>
			<td style="width:167px;">Amersham (GE)</td>
			<td style="width:119px;">10600015</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">gel box</td>
			<td style="width:167px;">Bio-Rad</td>
			<td>1658005</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Tris</td>
			<td style="width:167px;">Fisher Scientific</td>
			<td style="width:119px;">BP152-1</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Tween20</td>
			<td style="width:167px;">Sigma Aldrich</td>
			<td style="width:119px;">P-1379</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">sodium chloride</td>
			<td style="width:167px;">Fisher Scientific</td>
			<td style="width:119px;">S271-1</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">primary NEP polyclonal antibody&#160;</td>
			<td style="width:167px;">R &#38; D Systems</td>
			<td style="width:119px;">AF1182</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">doxycycline chow</td>
			<td style="width:167px;">Teklad (HARLAN)</td>
			<td>TD.130750&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">FVB/NJ wild type mice</td>
			<td style="width:167px;">Jackson</td>
			<td style="width:119px;">001800</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">secondary antibody (goat anti-rabbit)</td>
			<td style="width:167px;">ZyMed</td>
			<td style="width:119px;">81-6120</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">ECL solution-Western Lightening Plus</td>
			<td style="width:167px;">PerkinElmer</td>
			<td style="width:119px;">NEL104001EA</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">film</td>
			<td style="width:167px;">Pierce</td>
			<td style="width:119px;">34091</td>
			<td></td>
		</tr>
	</tbody>
</table>

an optimized evans blue protocol to assess vascular leak in the mouse

Vascular leak, or plasma extravasation, has a number of causes, and may be a serious consequence or symptom of an inflammatory response. This study may ultimately lead to new knowledge concerning the causes of or new ways to inhibit or treat plasma extravasation. It is important that researchers have the proper tools, including the best methods available, for studying plasma extravasation. In this article, we describe a protocol, using the Evans blue dye method, for assessing plasma extravasation in the organs of FVBN mice. This protocol is intentionally simple, to as great a degree as possible, but provides high quality data. Evans blue dye has been chosen primarily because it is easy for the average laboratory to use. We have used this protocol to provide evidence and support for the hypothesis that the enzyme neprilysin may protect the vasculature against plasma extravasation. However, this protocol may be experimentally used and easily adapted for use in other strains of mice or in other species, in many different organs or tissues, for studies which may involve other factors that are important in understanding, preventing, or treating plasma extravasation. This protocol has been extensively optimized and modified from existing protocols, and combines reliability, ease of use, economy, and general availability of materials and equipment, making this protocol superior for the average laboratory to use in quantifying plasma extravasation from organs.

In Figure 1, a schematic of the procedure is shown, which has been found to result in the most reliable and consistent substance P-induced plasma extravasation values from organs of FVBN mice. This procedure usually takes two days of work, separated by at least 48 h of waiting time. It is possible to spread it out even more, if this is done consistently for all experiments to be compared. For example, after the organs are isolated on Day 1, the organs can be ...

Watch this Scientific Journal Video about An Optimized Evans Blue Protocol to Assess Vascular Leak in the Mouse at JoVE.com

An Optimized Evans Blue Protocol to Assess Vascular Leak in the Mouse

In this article, an economical, optimized, and simple protocol is described which uses the Evans blue dye method for assessing plasma extravasation in the organs of FVBN mice that can be adapted for use in other strains, species, and other organs or tissues.

Vascular leak, or plasma extravasation, has a number of causes, and may be a serious consequence or symptom of an inflammatory response. This study may ...

The overall goal of this protocol is to assess and relatively quantitate plasma extravasation or leakage in the organs of mice or other small animal species using a modified Evans Blue Dye method. This method can help answer key questions in the vascular field such as, which endogenous or exogenous factors modify plasma extravasation in a specific species or organ of interest? The main advantage of this technique is that although catheterization requires a modest degree of surgical competence, the method provides durable venous access and is reproducible from mouse to mouse.Generally, individuals new to this method may struggle because of the modest surgical difficulty of the catheter placement. After weighing a 16 to 20-week-old adult FVB NJ mouse, confirm a lack of response to toe pinch and shave the ventral neck area of the animal. Place the mouse in the supine position on a preheated pad and tape all four paws to the surgical surface.Apply ointment to the animal's eyes to prevent drying. Make a one centimeter incision in the right ventral neck over the jugular vein. Apply one or two drops of 1-2%lidocaine to the incision area for pain management and to promote vasodilation.Isolate the right internal jugular vein via blunt dissection. Tie the vein off with a 4-0 suture and use a hemostat to gently retract the rostral end of the vessel. Using fine scissors, cut a hole about three millimeters caudal to the suture and approximately halfway through the diameter of the vein.Next, insert a PV1 polyvinyl catheter into the jugular vein through the hole and thread the catheter approximately 1.5 centimeters toward the caudal end of the vessel. Use a new 4-0 suture to tie the catheter securely within the caudal section of the vessel and tie the rostral part of the vessel to the outside of the catheter with the loose ends of the suture originally used to tie off the rostral jugular vein. Tack the skin loosely back together around the catheter with another piece of 4-0 suture to prevent dehydration, loss of body heat and tissue desiccation.Then, connect the catheter to a syringe containing heparinized saline and flush the catheter with the saline solution. To assess extravasation and leakage from the organ of interest, first inject 50 microliters of Evans Blue solution into the jugular vein catheter, followed by a small volume of heparinized saline to flush the line. Two minutes later, inject 100 microliters Substance P into the catheter, followed by a second flush of heparinized saline.Eighteen minutes after Substance P injection, open the chest cavity of the animal and gravity perfuse the heart and blood vessels with 50 milliliters of 50 millimolar sodium citrate solution to remove the excess Evans Blue from within the blood vessels. Harvest the organs and tissues of interest and remove any residual contents for each tissue as necessary. Rinse the organs in room temperature PBS, blot the organs with a lab wipe and cut each organ in half.Obtain the wet weights of each organ half on a balance and dry 1/2 of each organ on a piece of foil in a drying oven at 150 degrees Celsius for 48 hours. Then, place the other half of each organ in up to 200 microliters of formamide in a microfuge tube for 48 to 72 hours for Evans Blue Dye extraction. Neprilysin knockout mice demonstrate an increased Substance P-induced plasma extravasation from the urinary bladder compared to wild type animals suggesting a role for Neprilysin in the negative regulation of Substance P-induced plasma extravasation from the bladder.Doxycycline treatment of mice transgenic for the over expression of Neprilysin for one week to activate Neprilysin over expression indicates an additional role for this enzyme in duodenal extravasation as doxycycline-treated transgenic animals exhibit a significantly reduced Substance P-induced plasma extravasation from the duodenum compared to all three groups of animals that is not observed after doxycycline treatment of wild type or knockout animals. Once mastered, the catheterization, injection, and organ isolation steps can be completed in 45 to 55 minutes if they are performed properly. Allow an additional two to three days for the remainder of the protocol.When first learning this technique, it's important to repeat the procedure in at least 10-20 practice animals before performing an experiment. After watching this video, you should have a good understanding of how to assess and to relatively quantitate plasma extravasation or leakage in the organs of mice or other small animal species using this modified Evans Blue Dye method.

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Medicine

25.4K vistas.  University of Colorado Denver. The overall goal of this protocol is to assess and relatively quantitate plasma extravasation or leakage in the organs of mice or other small animal species using a modified Evans Blue Dye method. This method can help answer key questions in the vascular field such as, which endogenous or exogenous factors modify plasma extravasation in a specific species or organ of interest? The main advantage of this technique is that although catheterization requires a modest degree of surgical competence...