The work was funded by a CHIR operating grant (DJB).

The following experimental protocol was approved by the institution&#39;s animal care committee.
1. NeMO in Female Rats
<ol>
	<li>Preparation
	<ol>
		<li>Place a female Sprague-Dawley rat weighing around 200 g under 3% isoflurane anesthesia, weigh the animal, and shave and disinfect the prepubic area 3 times using an iodine surgical scrub.</li>
		<li>On a heating pad, tape hind limbs and tail down and catheterize the bladder with a 20-gauge angiocatheter, which is also gently taped down to prevent sliding.</li>
	</ol>
	</li>
	<li>Dissection
	<ol>
		<li>Use a scalpel to perform an 8 mm longitudinal skin incision from the palpable pubic symphysis towards the urethral meatus. Lift off the skin on either side to facilitate later wound closure.</li>
		<li>Dissect bluntly to identify the stented urethra by longitudinal spreading with fine scissors. Place fine self-retaining skin hooks to enhance exposure of the urethra.</li>
		<li>Perform some gentle longitudinal spreading using curved scissors dorsal to the urethra to develop the plane between urethra and vagina. Then, bluntly pass a 4-0 silk suture behind the urethra and prepare the double throw of a surgeon&#39;s knot.</li>
	</ol>
	</li>
	<li>Partial urethral obstruction
	<ol>
		<li>Remove the angiocatheter, place a 0.9 mm metal rod parallel to the urethra, and then tighten the knot around urethra and metal rod, so that the latter still slides out easily thereafter.</li>
		<li>Secure the knot with 3 more throws using gentle tension before removing the rod. Cut the suture ends about 3 mm long, or 4 mm if later release of obstruction is part of the experiment.</li>
	</ol>
	</li>
	<li>Wound closure
	<ol>
		<li>Approximate the paraurethral glands using a buried single stitch of absorbable braided suture 4-0.</li>
		<li>Close the skin with a buried horizontal mattress stitch using the same absorbable suture. Note:&#160;While it may seem unconventional to use an absorbable suture for a skin-penetrating stitch, we did not encounter complications such as wound infections, and that suture removal can be avoided. &#160;</li>
	</ol>
	</li>
	<li>After care
	<ol>
		<li>Inject buprenorphine 0.1 mg/kg subcutaneously before placing the rat in a recovery cage.</li>
		<li>Offer some soft recovery diet for the first 24 h to the single housed rat. After this period, house animals again in the same pairs as before the procedure provided they are doing well and belong to the same treatment group.</li>
		<li>Check the rats daily for bladder size and general well-being; record their weight at least weekly.</li>
	</ol>
	</li>
</ol>
2. NeMO in Female Mice
<ol>
	<li>Preparation
	<ol>
		<li>Place a female C57bl/6 mouse weighing around 18 g and proceed as detailed in step 1.1.1.</li>
		<li>Proceed as detailed in step 1.1.2, except use a 24-gauge angiocatheter.</li>
	</ol>
	</li>
	<li>Dissection
	<ol>
		<li>Use a scalpel to perform a 6 mm longitudinal skin incision from the palpable pubic symphysis towards the urethral meatus.</li>
		<li>Dissect bluntly to identify the stented urethra by longitudinal spreading with fine scissors. Lift off the neuro-vascular bundle running ventrally on the urethra by analogous blunt dissection.</li>
		<li>Perform some gentle longitudinal spreading using curved scissors dorsal to the urethra to develop the plane between urethra and vagina. Then, bluntly pass a 5-0 non-absorbable braided suture behind the urethra and prepare the double throw of a surgeon&#39;s knot.</li>
	</ol>
	</li>
	<li>Partial urethral obstruction
	<ol>
		<li>Connect the angiocatheter with a 1 mL syringe and inject 0.1 mL of normal saline into the bladder.</li>
		<li>Place a 26-gauge cannula parallel to the urethra. Gently tighten the knot around urethra and cannula while pulling back the angiocath.</li>
		<li>Secure the knot with 3 more throws using gentle tension before removing the cannula.</li>
		<li>Test for urine appearing at the meatus upon gentle pressure on the animal&#39;s bladder; loosen the tie if unable to express urine. Otherwise, cut the suture ends about 3 mm long.</li>
	</ol>
	</li>
	<li>Wound closure
	<ol>
		<li>Close the skin with a buried horizontal mattress stitch using a 5-0 braided absorbable suture.</li>
	</ol>
	</li>
	<li>After care
	<ol>
		<li>Inject 0.1 mg/kg buprenorphine subcutaneously before placing the mouse in a recovery cage.</li>
		<li>Offer some soft recovery diet for the first 48 h to the single housed mouse. After this period, house animals again in the same groups as before the procedure provided they are doing well and belong to the same treatment group. 
		NOTE: Mice with a palpable distended bladder 24 h after the procedure that do not void when handled are over-obstructed and will die within the next 1 - 2 days unless taken back under anesthesia for removal of the obstructing ligature.</li>
		<li>Check the mice daily for bladder size and general well-being; record their weight at least weekly.</li>
	</ol>
	</li>
</ol>

<ol>
	<li>Andersson, K. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Storage+and+voiding+symptoms:+pathophysiologic+aspects.">Storage and voiding symptoms: pathophysiologic aspects.</a> Urology. 62 (5), 3-10 (2003).</li><li>Boyle, 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=The+prevalence+of+lower+urinary+tract+symptoms+in+men+and+women+in+four+centres.+The+UrEpik+study.">The prevalence of lower urinary tract symptoms in men and women in four centres. The UrEpik study.</a> BJU Int. 92 (4), 409-414 (2003).</li><li>Coyne, K. S., Wein, A., Nicholson, S., Kvasz, M., Chen, C. I., Milsom, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Economic+burden+of+urgency+urinary+incontinence+in+the+United+States:+a+systematic+review.">Economic burden of urgency urinary incontinence in the United States: a systematic review.</a> J Manag Care Pharm. 20 (2), 130-140 (2014).</li><li>Buttyan, R., Chen, M. W., Levin, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Animal+models+of+bladder+outlet+obstruction+and+molecular+insights+into+the+basis+for+the+development+of+bladder+dysfunction.">Animal models of bladder outlet obstruction and molecular insights into the basis for the development of bladder dysfunction.</a> Eur. Urol. 32 (Suppl 1), 32-39 (1997).</li><li>Mattiasson, A., Uvelius, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Changes+in+contractile+properties+in+hypertrophic+rat+urinary+bladder.">Changes in contractile properties in hypertrophic rat urinary bladder.</a> J Urol. 128 (6), 1340-1342 (1982).</li><li>Chang, 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=Alteration+of+the+PKC-mediated+signaling+pathway+for+smooth+muscle+contraction+in+obstruction-induced+hypertrophy+of+the+urinary+bladder.">Alteration of the PKC-mediated signaling pathway for smooth muscle contraction in obstruction-induced hypertrophy of the urinary bladder.</a> Lab Invest. 89 (7), 823-832 (2009).</li><li>Moore, J. A., Brading, A. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+porcine+model+of+bladder+outlet+obstruction+incorporating+radio-telemetered+cystometry.">A porcine model of bladder outlet obstruction incorporating radio-telemetered cystometry.</a> BJU Int. 100 (5), 1192-1193 (2007).</li><li>Beamon, C. R., Mazar, C., Salkini, M. W., Phull, H. S., Comiter, C. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+effect+of+sildenafil+citrate+on+bladder+outlet+obstruction:+a+mouse+model.">The effect of sildenafil citrate on bladder outlet obstruction: a mouse model.</a> BJU Inte. 104 (2), 252-256 (2009).</li><li>Pandita, R. K., Fujiwara, M., Alm, P., Andersson, K. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cystometric+evaluation+of+bladder+function+in+non-anesthetized+mice+with+and+without+bladder+outlet+obstruction.">Cystometric evaluation of bladder function in non-anesthetized mice with and without bladder outlet obstruction.</a> J Urol. 164 (4), 1385-1389 (2000).</li><li>Kang, Y. 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=Early+Sequential+Changes+in+Bladder+Function+after+Partial+Bladder+Outlet+Obstruction+in+Awake+Sprague-Dawley+Rats:+Focus+on+the+Decompensated+Bladder.">Early Sequential Changes in Bladder Function after Partial Bladder Outlet Obstruction in Awake Sprague-Dawley Rats: Focus on the Decompensated Bladder.</a> Korean J Urol. 52 (12), 835-837 (2011).</li><li>Schroeder, 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=Protective+effect+of+an+oral+endothelin+converting+enzyme+inhibitor+on+rat+detrusor+function+after+outlet+obstruction.">Protective effect of an oral endothelin converting enzyme inhibitor on rat detrusor function after outlet obstruction.</a> J Urol. 172 (3), 1171-1174 (2004).</li><li>Sidler, M., Aitken, K., Jiang, J., Bijos, D., B&#228;gli, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term="sometimes+a+sham+is+just+a+sham"+-+why+the+rodent+model+of+partial+bladder+outlet+obstruction+needs+adjustment.">"sometimes a sham is just a sham" - why the rodent model of partial bladder outlet obstruction needs adjustment.</a> J Urol. 195 (4), e379 (2016).</li><li>Jin, L. 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=Persistent+detrusor+overactivity+in+rats+after+relief+of+partial+urethral+obstruction.">Persistent detrusor overactivity in rats after relief of partial urethral obstruction.</a> Am. J. Physiol. Regul. Integr. Comp. Physiol. 301 (4), R896-R904 (2011).</li></ol>

The authors have nothing to disclose.

Animal mortality is one of the major concerns of the traditional model of pBOO at the proximal urethra, at 15% or more in many reports10,11,13. NeMO appears to have minimal mortality when applied in female rats. Proximal urethral obstruction in mice is technically more challenging than in rats and thus even more prone to complications. Using a 26-gauge cannula as a placeholder for our mid-urethral approach, we h...

Partial bladder outlet obstruction (pBOO) has a high prevalence and can result in severe bladder dysfunction1; the spectrum ranges from congenital malformations such as posterior urethral valves or hypospadias, over acquired urethral strictures to benign prostatic hyperplasia. The latter affecting more than 30% of men sixty years and older2. Great patient burden and immense health care costs associated with pBOO warrant the considerable research effort put into studying bladder remodeling in response to increased outflow resistance3. From 2006 until 2015, over 220 PubMed indexed articles were published concerning the effect of pBOO on the urinary bladder.
Although animal models for pBOO have been devised in several species4, such as the rat5, the rabbit6, pig7, and mouse8,9, arguably the most commonly used animal model however are female rats undergoing partial obstruction of the proximal urethra; access to the animals&#39; abdomen, exteriorizing of the bladder, and dissection around the bladder neck are inevitable with this traditional proximal urethral obstruction technique. Variability in the degree of obstruction and animal mortality are only some of the concerns associated with this procedure10,11; we showed that in sham operated animals, dissection around the proximal urethra leads to physiologic changes that correlate with loss of nerve fibers at the bladder neck12. This finding indicates, that the most commonly used pBOO animal model, which involves accessing the proximal urethra in female rodents, leads to a denervation injury with associated structural and functional changes of the bladder, affecting sham and obstructed animals. Therefore, an alternate approach avoiding denervation injury was needed. Our lab developed and evaluated a Nerve-sparing Mid-urethral Obstruction (NeMO) approach, effective in inducing expected obstruction-associated changes in the bladder such as increase in organ mass and residual urine, whilst sham-operated animals were indistinguishable from unoperated control animals. Also, the striated urethral sphincter remained untouched as it lies proximal to the level of dissection. Furthermore, variability in obstruction-induced increase in bladder mass was significantly lower than in traditional proximal urethral obstruction and animal mortality was zero.
We also successfully applied NeMO in female mice with a less than 10% mortality in obstructed animals, while all pBOO models for mice described to date were associated with a mortality around 50%. Studying bladder remodeling in the context of pBOO in mice will benefit from applicability of the whole spectrum of transgenic modifications.
Dissecting around the mid-urethra in female rodents does not induce the undesirable and confounding structural or functional changes in the urinary bladder observed in the traditional proximal obstruction model. Nevertheless, inducing a partial obstruction at the mid-urethral level still induces bladder hypertrophy and increased residual urine, as expected from an animal model for pBOO. Importantly, performing NeMO in mice opens investigation of bladder remodeling in pBOO to transgenic methods, which are virtually unavailable in larger rodents.

<table border="0" cellpadding="0" cellspacing="0" width="1064">
	<tbody>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">Female rat&#160;</td>
			<td style="width:123px;">Charles-River Canada</td>
			<td style="width:559px;">Sprague Dawley Rat (Crl:SD); Strain Code: 400</td>
			<td style="width:167px;">about 200g</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">Isoflorane vaporizer</td>
			<td style="width:123px;">Benson medical industries inc.</td>
			<td style="width:559px;">TEC III Isoflurane; product code: 53-T3ISO&#160;</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">Isoflorane</td>
			<td style="width:123px;">Fresenius Kabi Animal Health</td>
			<td style="width:559px;">Isoflorane; product code CP0406V2</td>
			<td style="width:167px;">&#160;250ml bottle</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">Disposable scalpell</td>
			<td style="width:123px;">Ted Pella, Inc.</td>
			<td style="width:559px;">#15 Sterile, Stainless Steel Scalpels; catalogue number 549-9-15S</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">Microscopy forceps</td>
			<td style="width:123px;">Ted Pella, Inc.</td>
			<td style="width:559px;">Aesculap Microscopy Forceps, Finepoint, 115mm; product number 5443</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">Adson forceps</td>
			<td style="width:123px;">Ted Pella, Inc.</td>
			<td style="width:559px;">Aesculap Adson Dissection Forceps, Curved, 120mm; product number 5002-9</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">Curved surgical scissors</td>
			<td style="width:123px;">Ted Pella, Inc.</td>
			<td style="width:559px;">Surgical Scissors, Curved, S/S, 105mm; catalogue number 1376</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">0.9mm inox metal rod</td>
			<td style="width:123px;">goodfellow.com</td>
			<td style="width:559px;">Stainless Steel - AISI 316L Wire Diameter:0.9mm; order code 911-684-65</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">Skin hooks - self made from inox steel</td>
			<td style="width:123px;">goodfellow.com</td>
			<td style="width:559px;">Stainless Steel - AISI 316L Wire Diameter:0.9mm; order code 911-684-65</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">4-0 Silk suture</td>
			<td style="width:123px;">esutures.com</td>
			<td style="width:559px;">4-0 Sofsilk black 98&#34; strand; product number LS640</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">5-0 Vicry suture</td>
			<td style="width:123px;">esutures.com</td>
			<td style="width:559px;">5-0 Vicryl undyed 27&#34; RB-1 taper; product number J213H</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">Needle holder</td>
			<td style="width:123px;">Medsupplier.com</td>
			<td style="width:559px;">Integra Miltex Carb-N-Sert Baumgartner Needle Holder - 5 1/2&#34;; product code SKU NEE4484-8-40TC 
			SKU NEE4484-8-40TC 
			SKU NEE4484-8-40TC&#160;</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">Temgesic (Buprenorphine)</td>
			<td style="width:123px;">first veterinary supply</td>
			<td style="width:559px;">Buprenex 0.3MG/ml inj amps; item #075701</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">1ml syringe with 27G needle</td>
			<td style="width:123px;">Fisher Scientific</td>
			<td style="width:559px;">BD&#160;Tuberculin Syringe, BD 309623</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">20G Angiocath</td>
			<td style="width:123px;">Fisher Scientific</td>
			<td style="width:559px;">Andwin Scientific&#160;ANGIOCATH 20 GA; Catalog No. NC9561906</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">Recovery diet</td>
			<td style="width:123px;">clearh2o</td>
			<td>DietGel 31M; 72-08-5022</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">C57Bl/6 female mice</td>
			<td style="width:123px;">Charles-River Canada</td>
			<td style="width:559px;">C57BL/6 Mouse (C57BL/6NCrI); Strain Code: 027</td>
			<td style="width:167px;">about 18g</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">24G angiocath</td>
			<td style="width:123px;">Fisher Scientific</td>
			<td style="width:559px;">Hanna Pharmaceutical Supply Co., Inc.&#160;IV CATH ANGIOCATH 24GX3/4IN; Catalog No. NC9814340</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">5-0 Ethibond</td>
			<td style="width:123px;">esutures.com</td>
			<td style="width:559px;">5-0 Ethibond green 30&#34; RB-1 taper; product number X550H</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">26G syringe needle</td>
			<td style="width:123px;">Sigma-Aldrich</td>
			<td style="width:559px;">BD Precisionglide syringe needle, Gauge 26; z192392</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Normal Saline</td>
			<td style="width:123px;">Baxter</td>
			<td style="width:559px;">0.9% Sodium Chloride Injection, USP, 100 mL MINI-BAG; product code 2B0043</td>
			<td style="width:167px;"></td>
		</tr>
	</tbody>
</table>

nerve-sparing mid-urethral obstruction (nemo) in female small rodents

Partial bladder outlet obstruction (pBOO) has a high prevalence, causes significant patient burden, and immense health care costs. The most common animal model to investigate bladder remodeling in pBOO are female rodents undergoing partial obstruction at the proximal urethra. Variability in the degree of obstruction and animal mortality are major concerns with proximal obstruction. Furthermore, dissecting around the proximal urethra and bladder neck jeopardizes bladder innervation.
We developed a nerve-sparing mid-urethral obstruction (NeMO) model for pBOO avoiding the disadvantages of the traditional model. We approached the urethra just inferior to the pubic symphysis, which obviated the need for laparotomy as well as for dissection in this area; also, the striated urethral sphincter remained untouched. We performed NeMO in female Sprague-Dawley rats (12 obstructions, 6 sham animals) as well as in female C57/bl6 mice (20 obstructions, 18 sham animals). After two weeks, we evaluated bladder function, bladder mass, and body mass.
We had no mortalities among obstructed- or sham-operated female rats; as described for the traditional proximal pBOO-method, we tied the suture around the proximal urethra and a temporarily placed 0.9 mm metal rod. NeMO induced an 85% increase in bladder mass after two weeks, average residual urine volume was 0.4 mL in partially obstructed rats while only 0.03 mL in sham animals. In mice, we tested 3 sizes of cannulas that we placed along the urethra when tying the suture. We found that using a 27-gauge cannula resulted in over 50% animal mortality; placing the 25-gauge cannula did not yield the desired response in increasing bladder mass; utilizing a 26-gauge cannula yielded favorable results with minimal animal mortality (1/8) yet a significant 2-fold increase in bladder mass.

Nerve-sparing Mid-urethral Obstruction (NeMO) in Female Rats
Mortality
We performed a mid-urethral obstruction on over 40 female rats so far and had no mortalities.
Bladder mass
Average relative bladder mass (bladder-t...

Watch this Scientific Journal Video about Nerve-sparing Mid-urethral Obstruction NeMO in Female Small Rodents at JoVE.com

Nerve-sparing Mid-urethral Obstruction NeMO in Female Small Rodents

Traditional modeling of partial bladder outlet obstruction in rodents is fraught with animal mortality. A denervation injury from dissection around the proximal urethra and bladder neck is also of major concern. We developed and evaluated a safe and reliable mid-urethral obstruction model, avoiding the shortcomings of the traditional model.

Nerve-sparing Mid-urethral Obstruction (NeMO) in Female Small Rodents

Partial bladder outlet obstruction (pBOO) has a high prevalence, causes significant patient burden, and immense health care costs. The most common animal ...

nerve-sparing-mid-urethral-obstruction-nemo-in-female-small-rodents

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JoVE Journal

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9.5K Views.  The Hospital for Sick Children. Traditional modeling of partial bladder outlet obstruction in rodents is fraught with animal mortality. A denervation injury from dissection around the proximal urethra and bladder neck is also of major concern. We developed and evaluated a safe and reliable mid-urethral obstruction model, avoiding the shortcomings of the traditional model.

Video: Nerve-sparing Mid-urethral Obstruction NeMO in Female Small Rodents

Protocol for Long Duration Whole Body Hyperthermia in Mice

Hyperthermia is a general term used to define the increase in core body temperature above normal. It is often used to describe the increased core body temperature that is observed during fever. The use of hyperthermia as an adjuvant has emerged as a promising procedure for tumor regression in the field of cancer biology. For this purpose, the most important requirement is to have reliable and uniform heating protocols. We have developed a protocol for hyperthermia (whole body) in mice. In this protocol, animals are exposed to cycles of hyperthermia for 90 min followed by a rest period of 15 min. During this period mice have easy access to food and water. High body temperature spikes in the mice during first few hyperthermia exposure cycles are prevented by immobilizing the animal. Additionally, normal saline is administered in first few cycles to minimize the effects of dehydration. This protocol can simulate fever like conditions in mice up to 12-24 hr. We have used 8-12 weeks old BALB/Cj female mice to demonstrate the protocol.

This paper describes a protocol for whole body hyperthermia in mice that can stimulate fever like conditions up to 12-24 hr.

Hyperthermia is a general term used to define the increase in core body temperature above normal. It is often used to describe the increased core body ...

The Use of Cystometry in Small Rodents: A Study of Bladder Chemosensation

The lower urinary tract (LUT) functions as a dynamic reservoir that is able to store urine and to efficiently expel it at a convenient time. While storing urine, however, the bladder is exposed for prolonged periods to waste products. By acting as a tight barrier, the epithelial lining of the LUT, the urothelium, avoids re-absorption of harmful substances. Moreover, noxious chemicals stimulate the bladder's nociceptive innervation and initiate voiding contractions that expel the bladder's contents. Interestingly, the bladder's sensitivity to noxious chemicals has been used successfully in clinical practice, by intravesically infusing the TRPV1 agonist capsaicin to treat neurogenic bladder overactivity1. This underscores the advantage of viewing the bladder as a chemosensory organ and prompts for further clinical research. However, ethical issues severely limit the possibilities to perform, in human subjects, the invasive measurements that are necessary to unravel the molecular bases of LUT clinical pharmacology. A way to overcome this limitation is the use of several animal models2. Here we describe the implementation of cystometry in mice and rats, a technique that allows measuring the intravesical pressure in conditions of controlled bladder perfusion.
	After laparotomy, a catheter is implanted in the bladder dome and tunneled subcutaneously to the interscapular region. Then the bladder can be filled at a controlled rate, while the urethra is left free for micturition. During the repetitive cycles of filling and voiding, intravesical pressure can be measured via the implanted catheter. As such, the pressure changes can be quantified and analyzed. Moreover, simultaneous measurement of the voided volume allows distinguishing voiding contractions from non-voiding contractions3.
	Importantly, due to the differences in micturition control between rodents and humans, cystometric measurements in these animals have only limited translational value4. Nevertheless, they are quite instrumental in the study of bladder pathophysiology and pharmacology in experimental pre-clinical settings. Recent research using this technique has revealed the key role of novel molecular players in the mechano- and chemo-sensory properties of the bladder.

Cystometry is an efficient technique to measure bladder function of small animals in vivo. The bladder is continuously infused at rates controlled through an intravesical catheter, whereas the urethra is left free for micturition. This allows for repetitive filling and emptying of the bladder, while intravesical pressure and voided volume are recorded.

	The lower urinary tract (LUT) functions as a  dynamic reservoir that is able to store urine and to efficiently expel it at a  convenient time. While ...

Orthotopic Small Bowel Transplantation in Rats

Small bowel transplantation has become an accepted clinical option for patients with short gut syndrome and failure of parenteral nutrition (irreversible intestinal failure). In specialized centers improved operative and managing strategies have led to excellent short- and intermediate term patient and graft survival while providing high quality of life 1,3. Unlike in the more common transplantation of other solid organs (i.e. heart, liver) many underlying mechanisms of graft function and immunologic alterations induced by intestinal transplantation are not entirely known6,7. Episodes of acute rejection, sepsis and chronic graft failure are the main obstacles still contributing to less favorable long term outcome and hindering a more widespread employment of the procedure despite a growing number of patients on home parenteral nutrition who would potentially benefit from such a transplant. The small intestine contains a large number of passenger leucocytes commonly referred to as part of the gut associated lymphoid system (GALT) this being part of the reason for the high immunogenity of the intestinal graft. The presence and close proximity of many commensals and pathogens in the gut explains the severity of sepsis episodes once graft mucosal integrity is compromised (for example by rejection). To advance the field of intestinal- and multiorgan transplantation more data generated from reliable and feasible animal models is needed. The model provided herein combines both reliability and feasibility once established in a standardized manner and can provide valuable insight in the underlying complex molecular, cellular and functional mechanisms that are triggered by intestinal transplantation. We have successfully used and refined the described procedure over more than 5 years in our laboratory 8-11. The JoVE video-based format is especially useful to demonstrate the complex procedure and avoid initial pitfalls for groups planning to establish an orthotopic rodent model investigating intestinal transplantation.

Small bowel transplantation has become an accepted treatment option for patients with irreversible intestinal failure. Our experimental model of orthotopic small bowel transplantation in rats serves as a reliable tool to address underlying immunologic and inflammatory processes that complicate intestinal transplantation.

Small  bowel transplantation has become an accepted clinical option for patients with  short gut syndrome and failure of parenteral nutrition ...

Retinal Detachment Model in Rodents by Subretinal Injection of Sodium Hyaluronate

Subretinal injection of sodium hyaluronate is a widely accepted method of inducing retinal detachment (RD). However, the height and duration of RD or the occurrence of subretinal hemorrhage can affect photoreceptor cell death in the detached retina. Hence, it is advantageous to create reproducible RDs without subretinal hemorrhage for evaluating photoreceptor cell death. We modified a previously reported method to create bullous and persistent RDs in a reproducible location with rare occurrence of subretinal hemorrhage. The critical step of this modified method is the creation of a self-sealing scleral incision, which can prevent leakage of sodium hyaluronate after injection into the subretinal space. To make the self-sealing scleral incision, a scleral tunnel is created, followed by scleral penetration into the choroid with a 30 G needle. Although choroidal hemorrhage may occur during this step, astriction with a surgical spear reduces the rate of choroidal hemorrhage. This method allows a more reproducible and reliable model of photoreceptor death in diseases that involve RD such as rhegmatogenous RD, retinopathy of prematurity, diabetic retinopathy, central serous chorioretinopathy, and age-related macular degeneration (AMD).

Creating experimental retinal detachments with a reproducible and sustained height of detachment, and without subretinal hemorrhage, is important for studying the pathophysiology of photoreceptor cell loss in retinal disease and evaluating potential therapeutic interventions. Here, we report such a method in detail.

Subretinal injection of sodium hyaluronate is a widely accepted method of inducing retinal detachment (RD). However, the height and duration of RD or the ...

Remote Limb Ischemic Preconditioning:  A Neuroprotective Technique in Rodents

Sublethal ischemia protects tissues against subsequent, more severe ischemia through the upregulation of endogenous mechanisms in the affected tissue. Sublethal ischemia has also been shown to upregulate protective mechanisms in remote tissues. A brief period of ischemia (5-10 min) in the hind limb of mammals induces self-protective responses in the brain, lung, heart and retina. The effect is known as remote ischemic preconditioning (RIP). It is a therapeutically promising way of protecting vital organs, and is already under clinical trials for heart and brain injuries. This publication demonstrates a controlled, minimally invasive method of making a limb &#8211; specifically the hind limb of a rat &#8211; ischemic. A blood pressure cuff developed for use in human neonates is connected to a manual sphygmomanometer and used to apply 160 mmHg pressure around the upper part of the hind limb. A probe designed to detect skin temperature is used to verify the ischemia, by recording the drop in skin temperature caused by pressure-induced occlusion of the leg arteries, and the rise in temperature which follows release of the cuff. This method of RIP affords protection to the rat retina against bright light-induced damage and degeneration.

Remote ischemic preconditioning (RIP) is a method of conditioning tissues against damaging stress. We have established a method of remote ischemia at the hind limb, by inflating a sphygmomanometer cuff for 5-10 min. The neuroprotective capabilities of RIP have been demonstrated in a model of retinal degeneration in rodents.

Sublethal ischemia protects tissues against subsequent, more severe ischemia through the upregulation of endogenous mechanisms in the affected tissue. ...

Performing Subretinal Injections in Rodents to Deliver Retinal Pigment Epithelium Cells in Suspension

The conversion of light into electrical impulses occurs in the outer retina and is accomplished largely by rod and cone photoreceptors and retinal pigment epithelium (RPE) cells. RPE provide critical support for photoreceptors and death or dysfunction of RPE cells is characteristic of age-related macular degeneration (AMD), the leading cause of permanent vision loss in people age 55 and older. While no cure for AMD has been identified, implantation of healthy RPE in diseased eyes may prove to be an effective treatment, and large numbers of RPE cells can be readily generated from pluripotent stem cells. Several interesting questions regarding the safety and efficacy of RPE cell delivery can still be examined in animal models, and well-accepted protocols used to inject RPE have been developed. The technique described here has been used by multiple groups in various studies and involves first creating a hole in the eye with a sharp needle. Then a syringe with a blunt needle loaded with cells is inserted through the hole and passed through the vitreous until it gently touches the RPE. Using this injection method, which is relatively simple and requires minimal equipment, we achieve consistent and efficient integration of stem cell-derived RPE cells in between the host RPE that prevents significant amount of photoreceptor degeneration in animal models. While not part of the actual protocol, we also describe how to determine the extent of the trauma induced by the injection, and how to verify that the cells were injected into the subretinal space using in vivo imaging modalities. Finally, the use of this protocol is not limited to RPE cells; it may be used to inject any compound or cell into the subretinal space.

Here we present a community accepted protocol in multimedia format for subretinally injecting a bolus of RPE cells in rats and mice. This approach can be used for determining rescue potentials, safety profiles, and survival capacities of grafted RPE cells upon implantation in animal models of retinal degeneration.

The conversion of light into electrical impulses occurs in the outer retina and is accomplished largely by rod and cone photoreceptors and retinal pigment ...

A Murine Model of Irreversible and Reversible Unilateral Ureteric Obstruction

Obstruction of the kidney may affect native or transplanted kidneys and results in kidney injury and scarring. Presented here is a model of obstructive nephropathy induced by unilateral ureteric obstruction (UUO), which can either be irreversible (UUO) or reversible (R-UUO). In the irreversible UUO model, the ureter may be obstructed for variable periods of time in order to induce increasingly severe renal inflammation and interstitial fibrotic scarring. In the reversible R-UUO model the ureter is obstructed to induce hydronephrosis, tubular dilation and inflammation. After a suitable period of time the ureteric obstruction is then surgically reversed by anastomosis of the severed previously obstructed ureter to the bladder in order to allow complete decompression of the kidney and restoration of urinary flow to the bladder. The irreversible UUO model has been used to investigate various aspects of renal inflammation and scarring including the pathogenesis of disease and the testing of potential anti-inflammatory or anti-fibrotic therapies. The more challenging model of R-UUO has been used by some investigators and does offer significant research potential as it allows the study of inflammatory and immune processes and tissue remodeling in an injured and scarred kidney following the removal of the injurious stimulus. As a result, the R-UUO model offers investigators the opportunity to explore the resolution of kidney inflammation together with key aspects of tissue repair. These experimental models are of relevance to human disease as patients often present with obstruction of the renal tract that requires decompression and are commonly left with significant residual kidney impairment that has no current treatment options and may lead to eventual end stage kidney failure.

The murine model of irreversible unilateral ureteric obstruction (UUO) is presented together with the model of reversible UUO in which the ureteric obstruction is relieved by anastomosis of the severed ureter into the bladder. These models enable the study of renal inflammation and scarring as well as tissue remodeling.

Obstruction of the kidney may affect native or transplanted kidneys and results in kidney injury and scarring. Presented here is a model of obstructive ...

Transcutaneous Assessment of Renal Function in Conscious Rodents

Glomerular filtration rate (GFR) is the gold standard to assess overall kidney function. However, traditional methods to evaluate GFR are cumbersome and time-consuming. In addition, serial blood or urine samples are required, with the associated stress for the experimental animals. A recent technique significantly reduces the investment in time and resources, minimizing the invasiveness and the animal stress, but being equally valid as the traditional approaches. The method measures transcutaneously renal function. Using an optical device and the exogenous renal marker fluorescein isothiocyanate (FITC)-sinistrin, this technique is capable of measuring the elimination kinetics of the marker through the skin. With neither blood nor urine samples nor the associated laboratory assays needed, the results of the transcutaneous measurement are almost instantaneously available. The method has been already validated in different species and successfully applied in several models of renal pathology. Moreover, due to its minimally invasive characteristics, it is suitable for sequential measurements within the same animal. Here is provided a detailed protocol to carry out the transcutaneous assessment of renal function in rodents.

Determination of glomerular filtration rate (GFR) is the gold standard to assess overall kidney function. However, traditional procedures to measure this parameter are cumbersome and require a large investment of time. Here we describe a faster and minimally invasive method to determinate GFR transcutaneously.

Glomerular filtration rate (GFR) is the gold standard to assess overall kidney function. However, traditional methods to evaluate GFR are cumbersome and ...

An Efficient Sieving Method to Isolate Intact Glomeruli from Adult Rat Kidney

Preservation of glomerular structure and function is pivotal in the prevention of glomerulonephritis, a category of kidney disease characterized by proteinuria which can eventually lead to chronic and end-stage renal disease. The glomerulus is a complex apparatus responsible for the filtration of plasma from the body. In disease, structural integrity is lost and allows for the abnormal leakage of plasma contents into the urine. A method to isolate and examine glomeruli in culture is critical for the study of these diseases. In this protocol, an efficient method of retrieving intact glomeruli from adult rat kidneys while conserving structural and morphological characteristics is described. This process is capable of generating high yields of glomeruli per kidney with minimal contamination from other nephron segments. With these glomeruli, injury conditions can be mimicked by incubating them with a variety of chemical toxins, including protamine sulfate, which causes foot process effacement and proteinuria in animal models. Degree of injury can be assessed using transmission electron microscopy, immunofluorescence staining, and western blotting. Nephrin and Wilms Tumor 1 (WT1) levels can also be assessed from these cultures. Due to the ease and flexibility of this protocol, the isolated glomeruli can be utilized as described or in a way that best suits the needs of the researcher to help better study glomerular health and structure in diseased states.

The main focus of this protocol is to efficiently isolate viable primary glomeruli cultures with minimal contaminants for use in a variety of downstream applications. The isolated glomeruli retain structural relationships between component cell types and can be cultured ex vivo for a short time.

Preservation of glomerular structure and function is pivotal in the prevention of glomerulonephritis, a category of kidney disease characterized by ...

Studying Left Ventricular Reverse Remodeling by Aortic Debanding in Rodents

To better understand the left ventricular (LV) reverse remodeling (RR), we describe a rodent model wherein, after aortic banding-induced LV remodeling, mice undergo RR upon removal of the aortic constriction. In this paper, we describe a step-by-step procedure to perform a minimally invasive surgical aortic debanding in mice. Echocardiography was subsequently used to assess the degree of cardiac hypertrophy and dysfunction during LV remodeling and RR and to determine the best timing for aortic debanding. At the end of the protocol, terminal hemodynamic evaluation of the cardiac function was conducted, and samples were collected for histological studies. We showed that debanding is associated with surgical survival rates of 70-80%. Moreover, two weeks after debanding, the significant reduction of ventricular afterload triggers the regression of ventricular hypertrophy (~20%) and fibrosis (~26%), recovery of diastolic dysfunction as assessed by the normalization of left ventricular filling and end-diastolic pressures (E/e&#39;&#160;and LVEDP). Aortic debanding is a useful experimental model to study LV RR in rodents. The extent of myocardial recovery is variable between subjects, therefore, mimicking the diversity of RR that occurs in the clinical context, such as aortic valve replacement. We conclude that the aortic banding/debanding model represents a valuable tool to unravel novel insights into the mechanisms of RR, namely the regression of cardiac hypertrophy and the recovery of diastolic dysfunction.

Here we describe a step-by-step protocol of surgical aorta debanding in the well-established mice model of aortic-constriction. This procedure not only allows studying the mechanisms underlying the left ventricular reverse remodeling and regression of hypertrophy but also to test novel therapeutic options that might accelerate myocardial recovery.

To better understand the left ventricular (LV) reverse remodeling (RR), we describe a rodent model wherein, after aortic banding-induced LV remodeling, ...