The authors would like to thank Autumn Peterson for assistance with mouse photography, Daniel Thoresen for assistance with mice, and Drs. Nicole Ward and Abdelmadjid Belkadi for assistance with surgical denervation. These studies were supported by funding from the National Institute of Arthritis and Musculoskeletal and Skin Diseases (grants R00AR059796 and R01AR065409); the University of Michigan Department of Dermatology; the Biological Sciences Scholars Program; the Center for Organogenesis; the University of Michigan Comprehensive Cancer Center; and the John S. and Suzanne C. Munn Cancer Fund. S.C.P. was supported by funding from the National Institute of General Medical Sciences (grant T32 GM007315). This work was also supported by the NIH Intramural Research Program, Center for Cancer Research, National Cancer Institute.

All procedures described in this protocol were performed in accordance with regulations established by the University of Michigan Unit for Laboratory Animal Medicine.
1. Induce Genetic Recombination in Mice
Note: The Gli1tm3(cre/ERT2)Alj/J mouse strain (Gli1-CreERT2)13 enables targeting of tamoxifen-induced genetic recombination to TD epithelia. Cross this strain with B6.129S4-Gt(ROSA)26Sortm1Sor/J reporter mice (LacZ)22 to generate Gli1;LacZ animals to visualize TD cells by whole-mount staining below.
<ol>
	<li>Prepare tamoxifen solution to a concentration of 12.5 mg/ml in corn oil.
	<ol>
		<li>In a 1.5 ml tube, add up to 20 mg of crystalline tamoxifen, and then 1 ml of corn oil. Firmly tape the tube to a vortex mixer, and vortex continuously at the highest setting at RT until the tamoxifen has fully dissolved (2-4 hr), as confirmed by examining the tube under a dissecting microscope for the absence of tamoxifen particulates.</li>
		<li>Transfer the solution to a 15 ml tube and dilute the tamoxifen to a final concentration of 12.5 mg/ml with additional corn oil. Mix by vortexing the viscous solution for an additional 30 sec. Store this solution for up to 1 week at 4 &#176;C in the dark.</li>
	</ol>
	</li>
	<li>Inject the tamoxifen solution intraperitoneally into Gli1;LacZ mice, at a volume of 200 &#181;l per 20 g of mouse body weight, for an effective tamoxifen dose of 2.5 mg per 20 g mouse weight.</li>
</ol>
2. Harvest Skin Biopsies
Note: Depending on the experiment, harvest skin biopsies several days to weeks after tamoxifen induction.&#160;For all surgeries, follow standard protocols for rodent surgery, including using sterile gloves, wearing a surgical mask or hair net, and covering the animal with a sterile surgical drape during the procedure.
<ol>
	<li>Prepare 10x stock anesthetic solution by mixing 90 mg/ml ketamine and 6.5 mg/ml xylazine in water. Dilute this stock solution 1:10 into sterile PBS just prior to use, and store at RT in the dark for up to 8 months.
	<ol>
		<li>Alternatively, anesthetize mice by isoflurane inhalation, beginning with a gas concentration of 4% with oxygen to fully anesthetize the animal, and then subsequently lowering this to 1-2% for the duration of the procedure.</li>
	</ol>
	</li>
	<li>Inject the anesthetic solution intraperitoneally at a dose of 200 &#181;l per 20 g mouse body weight. Check that the animal has reached the proper plane of sedation by toe pinch assay, and confirm that heart and respiratory rates are normal (approximately 600 beats and 160 breaths per min, respectively).</li>
	<li>Use an electric clipper to remove the hair from the site of biopsy on the dorsal back skin, being careful not to nick or damage the underlying skin.</li>
	<li>Prepare the surgical site by wiping the shaved area in an anterior-to-posterior direction using Betadine and alcohol wipes. Ensure all hair clippings are removed from the site.</li>
	<li>Outline the biopsy site using a black marker,&#160;&#160;place the animal on a warming pad in an aseptic surgical area, and cover with a sterile surgical drape (for demonstration purposes, sterile drape was omitted to increase visibility).&#160; &#160; 
	Note: To obtain longitudinal sections of hair follicles, the longer edge of the biopsy (the edge to be sectioned for histology, ~1 cm) should run in an anterior-posterior direction (parallel to the direction of the hair follicles), parasagital to the dorsal midline (Figure 1A).</li>
	<li>Use a sterile #11 scalpel to make a full thickness excision along the marked area without damaging the underlying muscular fascia. 
	Note: The excised skin tissue includes the epidermis, dermis, subcutaneous fat and panniculus carnosus. Bleeding is typically minimal.</li>
	<li>Flatten the excised skin sample on a dry paper towel, dermis side down, trim away the excess paper towel, and store the sample in cold PBS for up to 1 hr if other samples need to be collected. When ready, proceed to Steps 3.1 or 3.2 to process samples for histology, or Step 4 for whole-mount &#946;-galactosidase (LacZ) staining.</li>
	<li>Suture close the biopsy site using 6-0 nylon sutures, in a simple interrupted pattern spaced roughly 3 mm apart.</li>
	<li>Do not return mice that have undergone surgery into the same cage as other animals until after full recovery.</li>
	<li>Monitor animals immediately after surgery until they regain consciousness, and also daily until the surgical area has healed, typically within 1 week. Use analgesics in accordance with designated institutional animal care and use guidelines if mice exhibit signs of pain or distress. Remove sutures within 7-10 days after surgery. 
	Note: If needed, prepare analgesic solution by diluting carprofen (50 mg/ml stock solution) 1:100 in sterile water.&#160;&#160;Inject the solution subcutaneously between the shoulder blades near the scruff of the neck, at a dose of 200 &#181;l per 20 g body weight (5 mg/kg mouse body weight).</li>
</ol>
3. Process Samples for Histology
Note: To fix and process the excised tissue, use either method below depending on application.
<ol>
	<li>To generate paraffin-embedded histological samples, fix the skin in 3.7% formalin in PBS O/N at RT and store in 70% ethanol for up to 2 weeks. Remove the paper towel before embedding into paraffin.</li>
	<li>For generating frozen histological samples, submerge the tissue in cold 4% paraformaldehyde in PBS and gently shake for 1 hr. Remove the solution and wash the sample with 3 changes of PBS, roughly 5 min each. Next, submerge the sample in 30% sucrose in PBS to cryoprotect the tissue (&#34;sucrose sinking&#34;).</li>
	<li>Incubate with gentle shaking O/N at 4 &#176;C. The next day, remove the paper towel and trim away excess adipose tissue from the dermal side of the skin. Embed the tissue directly into OCT and store the frozen block at -80 &#176;C. 
	Note: After sectioning, either paraffin or frozen samples can be stained by immunohistochemistry to identify TDs, Merkel cells and nerves using antibodies against Keratin 17, Keratin 8 and Neurofilament, respectively, as previously described5,19.</li>
</ol>
4. Visualize Samples by Whole-mount LacZ Staining
<ol>
	<li>Prepare X-gal staining solution.
	<ol>
		<li>Combine 0.94 g sodium phosphate monobasic, and 2.6 g sodium phosphate dibasic in 250 ml of sterile water. Adjust pH to 7.3. To this, add 0.5 ml of 1 M magnesium chloride, 0.528 g of potassium ferrocyanide, and 0.412 g of potassium ferricyanide. Add 250 &#181;l of octylphenyl-polyethylene glycol and 125 mg of deoxycholate. The base solution can be stored at 4 &#176;C for up to 6 months in the dark.</li>
		<li>Prepare 50x stock X-gal solution by adding dimethylformamide to the X-gal stock bottle to generate a 50 mg/ml solution. Store this solution at -20 &#176;C in the dark.</li>
		<li>Just prior to use, dilute stock X-gal solution 1:50 into X-gal base solution to generate staining solution. For smaller biopsies (&#60;1 cm2), aliquot 1-2 ml of staining solution per sample.</li>
	</ol>
	</li>
	<li>Fix the skin sample collected in Step 2.7 in a solution containing 2% paraformaldehyde/0.2% glutaraldehyde in cold PBS for 30 min, gently shaking on ice. For smaller biopsies (&#60;1 cm2), use 1-2 ml of fixative solution per sample. 
	Note: Alternatively, fix samples in 2-4% paraformaldehyde only, or in 0.5% glutaraldehyde only. Optimal fixation conditions depend on the tissue, degree of LacZ expression and application.</li>
	<li>Remove the fixative solution, and rinse samples with 3 changes of PBS, 5 min each, on a shaker at RT.</li>
	<li>Remove the paper towel underneath the sample and cut away excess adipose tissue from the dermal side of the skin by gripping the fat with blunt forceps and trimming with dissecting scissors.</li>
	<li>Submerge the sample in X-gal staining solution, and incubate at 37 &#176;C O/N. LacZ expression will be visible as a blue stain under a dissecting microscope (Figure 1B). 
	Note: If the signal intensity is weak, replace the staining solution the next day and repeat the O/N incubation. If the background staining is too intense, reduce the time of staining, or incubate the sample at RT instead of 37 &#176;C.</li>
	<li>Remove the staining solution and wash the samples in 3 changes of PBS containing 3% DMSO for approximately 5 min, gently shaking at RT.</li>
	<li>Wash samples in 2-3 changes of 70% ethanol for 5 min&#160;each. Store samples in 70% ethanol.</li>
</ol>
5. Surgical Denervation
<ol>
	<li>Anesthetize the animal as in Step 2.2 and shave the entire dorsal skin.</li>
	<li>Prepare the surgical area of the back skin using Betadine and alcohol wipes,&#160;and cover the animal with a sterile surgical drape (for demonstration purposes, sterile drape was omitted to increase visibility).&#160;&#160;Keep the animal warm using a heating pad while operating in an aseptic surgical area.</li>
	<li>Make an incision using a sterile #11 scalpel along the dorsal midline from the base of the neck to roughly 0.5 cm above the tail.</li>
	<li>Using blunt forceps, gently reflect the skin on the left side away from the flank to visualize the underlying tissue from the scapular fat pads near the neck to just above the hind limb. 
	Note: Dorsal cutaneous nerves appear as white strands that travel caudally through the translucent fascia of the trunk wall before making sharp bends and entering the loose connective tissue underneath the skin (Figure 2).</li>
	<li>Using ultra-fine forceps under a dissecting light microscope, remove the nerves exclusively from the left side of the animal located at anatomical sites T3-12 by plucking from where the segments bend at the trunk wall to their entry sites into the skin (Figure 2).
	<ol>
		<li>Orient forceps vertically and remove the nerves by grasping approximately 0.5 cm below their bend sites and pulling upwards, causing the nerve to stretch and separate from the surrounding tissue (Figure 2C-E). Be careful to avoid rupturing adjacent blood vessels.</li>
		<li>Continue until all nerves extending from the trunk wall to the skin are removed. Do not disrupt the nerves within the dense fascia of the trunk wall. Keep the tissue moist throughout the procedure by periodically applying drops of sterile 0.9% saline solution.</li>
		<li>Alternatively, remove nerves by grasping their proximal ends near the trunk wall with forceps and snipping with fine scissors. Afterwards, sever the distal ends near the skin (Figures 2F-H). Finally, remove the intervening nerve segments (Figure 2I).</li>
	</ol>
	</li>
	<li>Remove any nerves from the skin flap exposed in Step 5.4. These fibers comprise the distal branches of the dorsal cutaneous nerves and appear as white branching strands located sporadically within the connective tissue on the dermal side of the skin flap (Figures 2J-K).
	<ol>
		<li>To remove these fine branches, position the fine forceps roughly parallel to the dermal surface, grasp the nerves and pluck upwards to avoid disrupting blood vessels and puncturing the skin. Continue until all visible nerves have been removed.</li>
	</ol>
	</li>
	<li>Using blunt dissection, reflect the skin on the right side of the dorsal midline incision, but do not remove the nerves. This will serve as the contralateral sham-operated control.</li>
	<li>Suture along the dorsal midline in a simple interrupted pattern&#160;&#160;to close the incision. Monitor the animal during recovery and post-operatively as previously demonstrated (Steps 2.8-10). Remove sutures within 7-10 days after surgery.</li>
	<li>To functionally assess stable denervation up to several weeks after surgery, remove the hair from the dorsal skin using an electric clipper.</li>
	<li>Gently prick the denervated skin area using a hypodermic needle, and note whether the animal responds, typically by shuddering or turning its head. If the skin area has been stably denervated, the animal will exhibit little or no response.</li>
	<li>Using a black marker, outline the area of no response, as well as an area of similar size and location on the contralateral sham side.</li>
	<li>Collect biopsies from these sites as in Steps 2.1-2.9 for analysis. 
	Note: Alternatively, the entire dorsal back skin, including denervated and sham-operated regions, can be removed as a single sheet for whole-mount staining, similar to as described in Step 4.</li>
</ol>

<ol>
	<li>Magnon, 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=Autonomic+nerve+development+contributes+to+prostate+cancer+progression.">Autonomic nerve development contributes to prostate cancer progression.</a> Science. 341, 1236361 (2013).</li><li>Zhao, C. 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=Denervation+suppresses+gastric+tumorigenesis.">Denervation suppresses gastric tumorigenesis.</a> Sci Transl Med. 6, 115 (2014).</li><li>Chiu, I. M., von Hehn, C. A., Woolf, C. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neurogenic+inflammation+and+the+peripheral+nervous+system+in+host+defense+and+immunopathology.">Neurogenic inflammation and the peripheral nervous system in host defense and immunopathology.</a> Nat Neurosci. 15, 1063-1067 (2012).</li><li>Gautron, L., Elmquist, J. K., Williams, K. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neural+control+of+energy+balance:+translating+circuits+to+therapies.">Neural control of energy balance: translating circuits to therapies.</a> Cell. 161, 133-145 (2015).</li><li>Peterson, S. 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=Basal+cell+carcinoma+preferentially+arises+from+stem+cells+within+the+hair+follicle+and+mechanosensory+niches.">Basal cell carcinoma preferentially arises from stem cells within the hair follicle and mechanosensory niches.</a> Cell Stem Cell. 16, 400-412 (2015).</li><li>Ostrowski, S. M., Belkadi, A., Loyd, C. M., Diaconu, D., Ward, N. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cutaneous+denervation+of+psoriasiform+mouse+skin+improves+acanthosis+and+inflammation+in+a+sensory+neuropeptide-dependent+manner.">Cutaneous denervation of psoriasiform mouse skin improves acanthosis and inflammation in a sensory neuropeptide-dependent manner.</a> J Invest Dermatol. 131, 1530-1538 (2011).</li><li>Ward, N. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Botulinum+neurotoxin+A+decreases+infiltrating+cutaneous+lymphocytes+and+improves+acanthosis+in+the+KC-Tie2+mouse+model.">Botulinum neurotoxin A decreases infiltrating cutaneous lymphocytes and improves acanthosis in the KC-Tie2 mouse model.</a> J Invest Dermatol. 132, 1927-1930 (2012).</li><li>Roggenkamp, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Epidermal+nerve+fibers+modulate+keratinocyte+growth+via+neuropeptide+signaling+in+an+innervated+skin+model.">Epidermal nerve fibers modulate keratinocyte growth via neuropeptide signaling in an innervated skin model.</a> J Invest Dermatol. 133, 1620-1628 (2013).</li><li>Riol-Blanco, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nociceptive+sensory+neurons+drive+interleukin-23-mediated+psoriasiform+skin+inflammation.">Nociceptive sensory neurons drive interleukin-23-mediated psoriasiform skin inflammation.</a> Nature. 510, 157-161 (2014).</li><li>Zanchi, 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=Botulinum+toxin+type-A+for+the+treatment+of+inverse+psoriasis.">Botulinum toxin type-A for the treatment of inverse psoriasis.</a> J Eur Acad Dermatol Venereol. 22, 431-436 (2008).</li><li>Farber, E. M., Lanigan, S. W., Rein, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+role+of+psychoneuroimmunology+in+the+pathogenesis+of+psoriasis.">The role of psychoneuroimmunology in the pathogenesis of psoriasis.</a> Cutis. 46, 314-316 (1990).</li><li>Dewing, S. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Remission+of+psoriasis+associated+with+cutaneous+nerve+section.">Remission of psoriasis associated with cutaneous nerve section.</a> Arch Dermatol. 104, 220-221 (1971).</li><li>Brownell, I., Guevara, E., Bai, C. B., Loomis, C. A., Joyner, A. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nerve-derived+sonic+hedgehog+defines+a+niche+for+hair+follicle+stem+cells+capable+of+becoming+epidermal+stem+cells.">Nerve-derived sonic hedgehog defines a niche for hair follicle stem cells capable of becoming epidermal stem cells.</a> Cell Stem Cell. 8, 552-565 (2011).</li><li>Liao, X. H., Nguyen, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Epidermal+expression+of+Lgr6+is+dependent+on+nerve+endings+and+Schwann+cells.">Epidermal expression of Lgr6 is dependent on nerve endings and Schwann cells.</a> Exp Dermatol. 23, 195-198 (2014).</li><li>Lumpkin, E. A., Marshall, K. L., Nelson, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+cell+biology+of+touch.">The cell biology of touch.</a> J Cell Biol. 191, 237-248 (2010).</li><li>Maricich, S. 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=Merkel+cells+are+essential+for+light-touch+responses.">Merkel cells are essential for light-touch responses.</a> Science. 324, 1580-1582 (2009).</li><li>Reinisch, C. M., Tschachler, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+touch+dome+in+human+skin+is+supplied+by+different+types+of+nerve+fibers.">The touch dome in human skin is supplied by different types of nerve fibers.</a> Ann Neurol. 58, 88-95 (2005).</li><li>Doucet, Y. S., Woo, S. H., Ruiz, M. E., Owens, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+touch+dome+defines+an+epidermal+niche+specialized+for+mechanosensory+signaling.">The touch dome defines an epidermal niche specialized for mechanosensory signaling.</a> Cell Reports. 3, 1759-1765 (2013).</li><li>Xiao, 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=Neural+Hedgehog+signaling+maintains+stem+cell+renewal+in+the+sensory+touch+dome+epithelium.">Neural Hedgehog signaling maintains stem cell renewal in the sensory touch dome epithelium.</a> Proc Natl Acad Sci USA. 112, 7195-7200 (2015).</li><li>English, K. B., Van Norman, D. K. -. V., Horch, K. <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+chronic+denervation+in+type+I+cutaneous+mechanoreceptors+(Haarscheiben).">Effects of chronic denervation in type I cutaneous mechanoreceptors (Haarscheiben).</a> Anat Rec. 207, 79-88 (1983).</li><li>Burgess, P. R., English, K. B., Horch, K. W., Stensaas, L. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Patterning+in+the+regeneration+of+type+I+cutaneous+receptors.">Patterning in the regeneration of type I cutaneous receptors.</a> J Physiol. 236, 57-82 (1974).</li><li>Soriano, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generalized+lacZ+expression+with+the+ROSA26+Cre+reporter+strain.">Generalized lacZ expression with the ROSA26 Cre reporter strain.</a> Nat Genet. 21, 70-71 (1999).</li><li>Wright, M. 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=Atoh1++progenitors+maintain+the+Merkel+cell+population+in+embryonic+and+adult+mice.">Atoh1+ progenitors maintain the Merkel cell population in embryonic and adult mice.</a> J Cell Biol. 208, 367-379 (2015).</li><li>Kumar, A., Brockes, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nerve+dependence+in+tissue,+organ,+and+appendage+regeneration.">Nerve dependence in tissue, organ, and appendage regeneration.</a> Trends Neurosci. 35, 691-699 (2012).</li><li>Rinkevich, 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=Clonal+analysis+reveals+nerve-dependent+and+independent+roles+on+mammalian+hind+limb+tissue+maintenance+and+regeneration.">Clonal analysis reveals nerve-dependent and independent roles on mammalian hind limb tissue maintenance and regeneration.</a> Proc Natl Acad Sci USA. 111, 9846-9851 (2014).</li><li>Ueno, 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=Dependence+of+corneal+stem/progenitor+cells+on+ocular+surface+innervation.">Dependence of corneal stem/progenitor cells on ocular surface innervation.</a> Invest Ophthalmol Vis Sci. 53, 867-872 (2012).</li><li>Westphalen, C. 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=Long-lived+intestinal+tuft+cells+serve+as+colon+cancer-initiating+cells.">Long-lived intestinal tuft cells serve as colon cancer-initiating cells.</a> J Clin Invest. 124, 1283-1295 (2014).</li><li>Uhmann, 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=The+Hedgehog+receptor+Patched+controls+lymphoid+lineage+commitment.">The Hedgehog receptor Patched controls lymphoid lineage commitment.</a> Blood. 110, 1814-1823 (2007).</li><li>Lau, 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=Temporal+control+of+gene+deletion+in+sensory+ganglia+using+a+tamoxifen-inducible+Advillin-Cre-ERT2+recombinase+mouse.">Temporal control of gene deletion in sensory ganglia using a tamoxifen-inducible Advillin-Cre-ERT2 recombinase mouse.</a> Mol Pain. 7, 100 (2011).</li></ol>

The authors have nothing to disclose.

Nerves serve crucial functions not only in sensation, but also in mammalian organ development, maintenance and regeneration13,24-27. As nerves have recently been implicated in diverse skin disorders, the techniques described here can be used to study the requirement for innervation in a variety of animal disease models. Indeed, the unilateral denervation technique allows for the direct comparison of skin with either intact or disrupted nerves from the same mouse. This provides an ideal internal control to comp...

Over the past few years, there has been a widening appreciation for the influence of nerves on diseases not typically regarded as classical neuropathies1-4. In the skin, recent experimental evidence has suggested that sensory nerves can modulate diverse pathologies ranging from psoriasis to cancer5-9. This has been demonstrated using techniques such as surgical denervation and pharmacological inhibition of neural function in rodents. In the case of psoriasis, these studies have provided a mechanistic framework for understanding why human psoriatic plaques regress following loss of neural function7,10-12.
Cutaneous nerves can also affect gene expression13,14 and are critical for mechanosensing in normal skin15. In particular, touch dome (TD) epithelia are comprised of a patch of columnar epidermal cells in juxtaposition with neuroendocrine Merkel cells innervated by slowly adapting type 1 (SA1) nerve fibers16-18. TDs mediate light touch sensation and have been shown to display Hedgehog pathway activity5,19. TD maintenance depends on innervation20,21, as nerves secrete Hedgehog ligands to sustain normal TDs and their associated Merkel cells19. In addition, innervation promotes Hedgehog-dependent tumor formation from TD epithelia5. Together, these studies reinforce the notion that intricate molecular interactions occurring between nerves and the surrounding cells in their niche are crucial for normal TD physiology as well as disease.
To interrogate the nature of these interactions, we describe here a series of in vivo techniques for manipulating gene expression in the TD, as well as for harvesting skin biopsies for TD visualization after lineage tracing. Finally, we describe procedures for performing unilateral surgical denervation, wherein nerves are removed from one side of the mouse dorsal skin, while leaving the contralateral side intact as a sham internal control. Several weeks after surgery, denervated and sham control skin are compared to assess changes that occur when nerves are ablated. Although these techniques are described in the context of normal TDs, the denervation procedure has been used to examine the requirement for nerves in mouse models of psoriasis6, wound healing13 and tumorigenesis5. Finally, since the skin is amenable to repeated biopsies, this provides an opportunity to monitor the long-term fates of labeled cells or to assess disease progression over multiple time points.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Alcohol prep pads</td>
			<td>PDI</td>
			<td>B339</td>
			<td></td>
		</tr>
		<tr>
			<td>AnaSed (Xylazine)</td>
			<td>Lloyd</td>
			<td>NADA 139-236</td>
			<td></td>
		</tr>
		<tr>
			<td>Antibody, anti-Keratin 8</td>
			<td>Developmental Studies Hybridoma Bank</td>
			<td>TROMA-I</td>
			<td>rat antibody, use at 1:500 concentration</td>
		</tr>
		<tr>
			<td>Antibody, anti-Keratin 17</td>
			<td>Cell Signaling</td>
			<td>#4543</td>
			<td>rabbit antibody, use at 1:1,000 concentration</td>
		</tr>
		<tr>
			<td>Antibody, anti-Neurofilament</td>
			<td>Cell Signaling</td>
			<td>C28E10</td>
			<td>rabbit antibody, use at 1:500 concentration</td>
		</tr>
		<tr>
			<td>Betadine prep pads</td>
			<td>Medline</td>
			<td>MDS093917</td>
			<td></td>
		</tr>
		<tr>
			<td>Carprofen (Rimadyl)</td>
			<td>Zoetis</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Cordless rechargable clipper</td>
			<td>Wahl</td>
			<td>trimmer model 8900</td>
			<td></td>
		</tr>
		<tr>
			<td>Corn Oil</td>
			<td>Sigma-Aldrich</td>
			<td>C8267</td>
			<td></td>
		</tr>
		<tr>
			<td>Cryostat</td>
			<td>Leica</td>
			<td>CM1860</td>
			<td></td>
		</tr>
		<tr>
			<td>DAPI</td>
			<td>ThermoFisher Scientific</td>
			<td>D1306</td>
			<td>use at 1:1000 concentration</td>
		</tr>
		<tr>
			<td>Deoxycholate</td>
			<td>Sigma-Aldrich</td>
			<td>D6750</td>
			<td></td>
		</tr>
		<tr>
			<td>Depilatory Cream</td>
			<td>Nair</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>Dimethylforamide</td>
			<td>Sigma-Aldrich</td>
			<td>319937</td>
			<td></td>
		</tr>
		<tr>
			<td>Dimethyl Sulfoxide (DMSO)</td>
			<td>Sigma-Aldrich</td>
			<td>D8418</td>
			<td></td>
		</tr>
		<tr>
			<td>Glutaraldehyde</td>
			<td>Sigma-Aldrich</td>
			<td>G5882</td>
			<td></td>
		</tr>
		<tr>
			<td>ImmEdge Pen</td>
			<td>Vector Laboratories</td>
			<td>H-4000</td>
			<td></td>
		</tr>
		<tr>
			<td>Ketamine HCl</td>
			<td>Hospira</td>
			<td>NDC 0409-2051-05</td>
			<td></td>
		</tr>
		<tr>
			<td>Magnesium chloride</td>
			<td>Sigma</td>
			<td>M8266</td>
			<td></td>
		</tr>
		<tr>
			<td>Micro cover glass</td>
			<td>VWR</td>
			<td>48404-454</td>
			<td></td>
		</tr>
		<tr>
			<td>Micro Slides</td>
			<td>VWR</td>
			<td>48311-703</td>
			<td></td>
		</tr>
		<tr>
			<td>10% Neutral Buffered Formalin</td>
			<td>VWR</td>
			<td>BDH0502-4LP</td>
			<td></td>
		</tr>
		<tr>
			<td>6-0 nylon sutures</td>
			<td>DemeTECH</td>
			<td>NL166012F4P</td>
			<td></td>
		</tr>
		<tr>
			<td>Octylphenyl-polyethylene glycol</td>
			<td>Sigma-Aldrich</td>
			<td>I8896</td>
			<td></td>
		</tr>
		<tr>
			<td>O.C.T. Compound</td>
			<td>Sakura Tissue-Tek</td>
			<td>4583</td>
			<td></td>
		</tr>
		<tr>
			<td>Paraformaldehyde</td>
			<td>Sigma-Aldrich</td>
			<td>158127</td>
			<td></td>
		</tr>
		<tr>
			<td>Pottasium ferrocyanide</td>
			<td>Sigma-Aldrich</td>
			<td>P9387</td>
			<td></td>
		</tr>
		<tr>
			<td>Pottasium ferricyanide</td>
			<td>Sigma-Aldrich</td>
			<td>702587</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium phosphate monobasic</td>
			<td>Sigma-Aldrich</td>
			<td>P9791</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium phosphate dibasic</td>
			<td>Sigma-Aldrich</td>
			<td>S5136</td>
			<td></td>
		</tr>
		<tr>
			<td>Sucrose</td>
			<td>Sigma-Aldrich</td>
			<td>84097</td>
			<td></td>
		</tr>
		<tr>
			<td>Tamoxifen</td>
			<td>Sigma-Aldrich</td>
			<td>T5648-1G</td>
			<td></td>
		</tr>
		<tr>
			<td>Ultra fine forceps</td>
			<td>Dumont</td>
			<td>0103-5-PO</td>
			<td></td>
		</tr>
		<tr>
			<td>Vectashield</td>
			<td>Vector Laboratories</td>
			<td>H1000</td>
			<td></td>
		</tr>
		<tr>
			<td>X-gal</td>
			<td>Roche</td>
			<td>10 651 745 001</td>
			<td>Disolve in dimethylforamide to create 50x stock prior to use</td>
		</tr>
	</tbody>
</table>

cutaneous surgical denervation:  a method for testing the requirement for nerves in mouse models of skin disease

Cutaneous somatosensory nerves function to detect diverse stimuli that act upon the skin. In addition to their established sensory roles, recent studies have suggested that nerves may also modulate skin disorders including atopic dermatitis, psoriasis and cancer. Here, we describe protocols for testing the requirement for nerves in maintaining a cutaneous mechanosensory organ, the touch dome (TD). Specifically, we discuss methods for genetically labeling, harvesting and visualizing TDs by whole-mount staining, and for performing unilateral surgical denervation on mouse dorsal back skin. Together, these approaches can be used to directly compare TD morphology and gene expression in denervated as well as sham-operated skin from the same animal. These methods can also be readily adapted to examine the requirement for nerves in mouse models of skin pathology. Finally, the ability to repeatedly sample the skin provides an opportunity to monitor disease progression at different stages and times after initiation.

By generating mice expressing tamoxifen-inducible Gli1-CreERT2 and a LacZ reporter allele, it is possible to visualize TD epithelia and track the fates of these cells over time. The entire denervation procedure typically can be completed within 1 hr per mouse and should cause minimal distress to the animal.
Our previous studies have indicated that nerves are crucial for maintaining both normal TDs as well as th...

Watch this Scientific Journal Video about Cutaneous Surgical Denervation:  A Method for Testing the Requirement for Nerves in Mouse Models of Skin Disease at JoVE.com

Cutaneous Surgical Denervation:  A Method for Testing the Requirement for Nerves in Mouse Models of Skin Disease

This article includes detailed protocols for genetic labeling of mouse skin, surgical denervation, skin biopsy and visualizing labeled epithelia by whole-mount &#946;-galactosidase staining. These methods can be used to test the requirement for nerves in mouse models of normal and pathological skin.

Cutaneous somatosensory nerves function to detect diverse stimuli that act upon the skin. In addition to their established sensory roles, recent studies ...

cutaneous-surgical-denervation-method-for-testing-requirement-for

Research

JoVE Journal

Medicine

9.7K Views.  University of Michigan. This article includes detailed protocols for genetic labeling of mouse skin, surgical denervation, skin biopsy and visualizing labeled epithelia by whole-mount β-galactosidase staining. These methods can be used to test the requirement for nerves in mouse models of normal and pathological skin.

Video: Cutaneous Surgical Denervation:  A Method for Testing the Requirement for Nerves in Mouse Models of Skin Disease

Accurate and Simple Measurement of the Pro-inflammatory Cytokine IL-1&beta; using a Whole Blood Stimulation Assay

Inflammatory processes resulting from the secretion of soluble mediators by immune cells, lead to various manifestations in skin, joints and other tissues as well as altered cytokine homeostasis. The innate immune system plays a crucial role in recognizing pathogens and other endogenous danger stimuli. One of the major cytokines released by innate immune cells is Interleukin (IL)-1. Therefore, we utilize a whole blood stimulation assay in order to measure the secretion of inflammatory cytokines and specifically of the pro-inflammatory cytokine IL-1&beta; 1, 2, 3.
Patients with genetic dysfunctions of the innate immune system causing autoinflammatory syndromes show an exaggerated release of mature IL-1&beta; upon stimulation with LPS alone. In order to evaluate the innate immune component of patients who present with inflammatory-associated pathologies, we use a specific immunoassay to detect cellular immune responses to pathogen-associated molecular patterns (PAMPs), such as the gram-negative bacterial endotoxin, lipopolysaccharide (LPS). These PAMPs are recognized by pathogen recognition receptors (PRRs), which are found on the cells of the innate immune system 4, 5, 6, 7. A primary signal, LPS, in conjunction with a secondary signal, ATP, is necessary for the activation of the inflammasome, a multiprotein complex that processes pro-IL-1&beta; to its mature, bioactive form 4, 5, 6, 8, 9, 10.
The whole blood assay requires minimal sample manipulation to assess cytokine production when compared to other methods that require labor intensive isolation and culturing of specific cell populations. This method differs from other whole blood stimulation assays; rather than diluting samples with a ratio of RPMI media, we perform a white blood cell count directly from diluted whole blood and therefore, stimulate a known number of white blood cells in culture 2. The results of this particular whole blood assay demonstrate a novel technique useful in elucidating patient cohorts presenting with autoinflammatory pathophysiologies.

Accurate and Simple Measurement of the Pro-inflammatory Cytokine IL-1&#946; using a Whole Blood Stimulation Assay

We describe a simple immunoassay to measure the production of pro-inflammatory cytokines, such as IL-1 beta production, in patients presenting with autoinflammatory phenotypes. By activating cells in whole blood cultures with pathogen-associated molecular patterns, specifically with lipopolysaccharide, cytokine secretion can be conveniently evaluated in whole blood supernatants.

Inflammatory processes resulting from the secretion of soluble mediators by immune cells, lead to various manifestations in skin, joints and other tissues ...

Clinical Testing and Spinal Cord Removal in a Mouse Model for Amyotrophic Lateral Sclerosis (ALS)

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder resulting in progressive degeneration of motoneurons. Peak of onset is around 60 years for the sporadic disease and around 50 years for the familial disease. Due to its progressive course, 50% of the patients die within 30 months of symptom onset. In order to evaluate novel treatment options for this disease, genetic mouse models of ALS have been generated based on human familial mutations in the SOD gene, such as the SOD1 (G93A) mutation. Most important aspects that have to be evaluated in the model are overall survival, clinical course and motor function. Here, we demonstrate the clinical evaluation, show the conduction of two behavioural motor tests and provide quantitative scoring systems for all parameters. Because an in depth analysis of the ALS mouse model usually requires an immunohistochemical examination of the spinal cord, we demonstrate its preparation in detail applying the dorsal laminectomy method. Exemplary histological findings are demonstrated. The comprehensive application of the depicted examination methods in studies on the mouse model of ALS will enable the researcher to reliably test future therapeutic options which can provide a basis for later human clinical trials.

Clinical Testing and Spinal Cord Removal in a Mouse Model for Amyotrophic Lateral Sclerosis ALS

A mouse model for amyotrophic lateral sclerosis (ALS) is examined clinically and behaviorally. As a prerequisite for an accompanying immunohistological analysis the preparation of the spinal cord is depicted in detail.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder resulting in progressive degeneration of motoneurons. Peak of onset is around 60 ...

Mouse Models for Graft Arteriosclerosis

Graft arteriosclerois (GA), also called allograft vasculopathy, is a pathologic lesion that develops over months to years in transplanted organs characterized by diffuse, circumferential stenosis of the entire graft vascular tree. The most critical component of GA pathogenesis is the proliferation of smooth muscle-like cells within the intima. When a human coronary artery segment is interposed into the infra-renal aortae of immunodeficient mice, the intimas could be expand in response to adoptively transferred human T cells allogeneic to the artery donor or exogenous human IFN-&gamma; in the absence of human T cells. Interposition of a mouse aorta from one strain into another mouse strain recipient is limited as a model for chronic rejection in humans because the acute cell-mediated rejection response in this mouse model completely eliminates all donor-derived vascular cells from the graft within two-three weeks. We have recently developed two new mouse models to circumvent these problems. The first model involves interposition of a vessel segment from a male mouse into a female recipient of the same inbred strain (C57BL/6J). Graft rejection in this case is directed only against minor histocompatibility antigens encoded by the Y chromosome (present in the male but not the female) and the rejection response that ensues is sufficiently indolent to preserve donor-derived smooth muscle cells for several weeks. The second model involves interposing an artery segment from a wild type C57BL/6J mouse donor into a host mouse of the same strain and gender that lacks the receptor for IFN-&gamma; followed by administration of mouse IFN-&gamma; (delivered via infection of the mouse liver with an adenoviral vector. There is no rejection in this case as both donor and recipient mice are of the same strain and gender but donor smooth muscle cells proliferate in response to the cytokine while host-derived cells, lacking receptor for this cytokine, are unresponsive. By backcrossing additional genetic changes into the vessel donor, both models can be used to assess the effect of specific genes on GA progression. Here, we describe detailed protocols for our mouse GA models.

We describe protocols for our mouse graft arteriosclerois (GA) models which involve interposition of a mouse vessel segment into a recipient of the same inbred strain. By backcrossing additional genetic changes into the vessel donor, the model can assess the effect of specific genes on GA.

Graft arteriosclerois (GA),  also called allograft vasculopathy, is a pathologic lesion that develops over  months to years in transplanted organs ...

A Simple Method of Mouse Lung Intubation

A simple procedure to intubate mice for pulmonary function measurements would have several advantages in longitudinal studies with limited numbers or expensive animal. One of the reasons that this is not done more routinely is that it is relatively difficult, despite there being several published studies that describe ways to achieve it. In this paper we demonstrate a procedure that eliminates one of the major hurdles associated with this intubation, that of visualizing the trachea during the entire time of intubation. The approach uses a 0.5 mm fiberoptic light source that serves as an introducer to direct the intubation cannula into the mouse trachea. We show that it is possible to use this procedure to measure lung mechanics in individual mice over a time course of at least several weeks. The technique can be set up with relatively little expense and expertise, and it can be routinely accomplished with relatively little training. This should make it possible for any laboratory to routinely carry out this intubation, thereby allowing longitudinal studies in individual mice, thereby minimizing the number of mice needed and increasing the statistical power by using each mouse as its own control.

This paper describes a striaghforward and efficient method of intubating mice for pulmonary function measurements or pulmonary instillation, that allows the mice to recover and be studied at later times. The procedure involves an inexpensive fiberoptic light source that directly illuminates the trachea.

A  simple procedure to intubate mice for pulmonary function measurements would  have several advantages in longitudinal studies with limited numbers or  ...

Tibial Nerve Transection - A Standardized Model for Denervation-induced Skeletal Muscle Atrophy in Mice

The tibial nerve transection model is a well-tolerated, validated, and reproducible model of denervation-induced skeletal muscle atrophy in rodents. Although originally developed and used extensively in the rat due to its larger size, the tibial nerve in mice is big enough that it can be easily manipulated with either crush or transection, leaving the peroneal and sural nerve branches of the sciatic nerve intact and thereby preserving their target muscles. Thus, this model offers the advantages of inducing less morbidity and impediment of ambulation than the sciatic nerve transection model and also allows investigators to study the physiologic, cellular and molecular biologic mechanisms regulating the process of muscle atrophy in genetically engineered mice. The tibial nerve supplies the gastrocnemius, soleus and plantaris muscles, so its transection permits the study of denervated skeletal muscle composed of fast twitch type II fibers and/or slow twitch type I fibers. Here we demonstrate the tibial nerve transection model in the C57Black6 mouse. We assess the atrophy of the gastrocnemius muscle, as a representative muscle, at 1, 2, and 4 weeks post-denervation by measuring muscle weights and fiber type specific cross-sectional area on paraffin-embedded histologic sections immunostained for fast twitch myosin.

The tibial nerve transection model is a well-tolerated, validated, and reproducible model of skeletal muscle atrophy. The model surgical protocol is described and demonstrated in C57Black6 mice. &#160;

The tibial nerve transection model is a well-tolerated, validated, and reproducible model of denervation-induced skeletal muscle atrophy in rodents. ...

Mouse Kidney Transplantation: Models of Allograft Rejection

Rejection of the transplanted kidney in humans is still a major cause of morbidity and mortality. The mouse model of renal transplantation closely replicates both the technical and pathological processes that occur in human renal transplantation. Although mouse models of allogeneic rejection in organs other than the kidney exist, and are more technically feasible, there is evidence that different organs elicit disparate rejection modes and dynamics, for instance the time course of rejection in cardiac and renal allograft differs significantly in certain strain combinations. This model is an attractive tool for many reasons despite its technical challenges. As inbred mouse strain haplotypes are well characterized it is possible to choose donor and recipient combinations to model acute allograft rejection by transplanting across MHC class I and II loci. Conversely by transplanting between strains with similar haplotypes a chronic process can be elicited were the allograft kidney develops interstitial fibrosis and tubular atrophy. We have modified the surgical technique to reduce operating time and improve ease of surgery, however a learning curve still needs to be overcome in order to faithfully replicate the model. This study will provide key points in the surgical procedure and aid the process of establishing this technique.

Here, we present a protocol to study the immunology of rejection. The surgical model presented reports a short operating time and a concise technique. Depending on the donor-recipient strain combination, the transplanted kidney may develop acute cellular rejection or chronic allograft damage, defined by interstitial fibrosis and tubular atrophy.

Rejection of the transplanted kidney in humans is still a major cause of morbidity and mortality. The mouse model of renal transplantation closely ...

A Mouse Fetal Skin Model of Scarless Wound Repair

Early in utero, but not in postnatal life, cutaneous wounds undergo regeneration and heal without formation of a scar. Scarless fetal wound healing occurs across species but is age dependent. The transition from a scarless to scarring phenotype occurs in the third trimester of pregnancy in humans and around embryonic day 18 (E18) in mice. However, this varies with the size of the wound with larger defects generating a scar at an earlier gestational age. The emergence of lineage tracing and other genetic tools in the mouse has opened promising new avenues for investigation of fetal scarless wound healing. However, given the inherently high rates of morbidity and premature uterine contraction associated with fetal surgery, investigations of fetal scarless wound healing in vivo require a precise and reproducible surgical model. Here we detail a reliable model of fetal scarless wound healing in the dorsum of E16.5 (scarless) and E18.5 (scarring) mouse embryos.

During mammalian development, early gestational skin wounds heal without a scar. Here we detail a reliable and reproducible model of fetal scarless wound healing in the cutaneous dorsum of E16.5 (scarless) and E18.5 (scarring) mouse embryos.

Early in utero, but not in postnatal life, cutaneous wounds undergo regeneration and heal without formation of a scar. Scarless fetal wound healing occurs ...

Surgical Models of Gastroesophageal Reflux with Mice

Multiple surgical procedures have been reported to induce gastroesophageal reflux in animals. Herein, we report three surgical models with mice aiming to induce reflux of gastric contents, duodenal contents or mixed contents. Surgical procedures and general principles have been described in detail. A researcher with surgical experience should be able to grasp the technique after a short period of practice. After surgery, most mice can survive and develop reflux esophagitis similar to that in humans. However, it should be noted that histological differences between mouse and human esophagus are the inherent limitations of these surgical models. If used for research on Barrett&#8217;s esophagus and adenocarcinoma, these procedures may need to be combined with genetic modifications.

This article demonstrates surgical procedures of gastroesophageal reflux with mice. These models are useful tools for research on mechanisms and treatment of gastroesophageal reflux disease and potentially Barrett&#8217;s esophagus and esophageal adenocarcinoma.

Multiple surgical procedures have been reported to induce gastroesophageal reflux in animals. Herein, we report three surgical models with mice aiming to ...

Surgical Placement of Catheters for Long-term Cardiovascular Exercise Testing in Swine

This protocol describes the surgical procedure to chronically instrument swine and the procedure to exercise swine on a motor-driven treadmill. Early cardiopulmonary dysfunction is difficult to diagnose, particularly in animal models, as cardiopulmonary function is often measured invasively, requiring anesthesia. As many anesthetic agents are cardiodepressive, subtle changes in cardiovascular function may be masked. In contrast, chronic instrumentation allows for measurement of cardiopulmonary function in the awake state, so that measurements can be obtained under quiet resting conditions, without the effects of anesthesia and acute surgical trauma. Furthermore, when animals are properly trained, measurements can also be obtained during graded treadmill exercise.
Flow probes are placed around the aorta or pulmonary artery for measurement of cardiac output and around the left anterior descending coronary artery for measurement of coronary blood flow. Fluid-filled catheters are implanted in the aorta, pulmonary artery, left atrium, left ventricle and right ventricle for pressure measurement and blood sampling. In addition, a 20 G&#160;catheter is positioned in the anterior interventricular vein to allow coronary venous blood sampling.
After a week of recovery, swine are placed on a motor-driven treadmill, the catheters are connected to pressure and flow meters, and swine are subjected to a five-stage progressive exercise protocol, with each stage lasting 3 min. Hemodynamic signals are continuously recorded and blood samples are taken during the last 30 sec of each exercise stage.
The major advantage of studying chronically instrumented animals is that it allows serial assessment of cardiopulmonary function, not only at rest but also during physical stress such as exercise. Moreover, cardiopulmonary function can be assessed repeatedly during disease development and during chronic treatment, thereby increasing statistical power and hence limiting the number of animals required for a study.

Here we present a protocol to assess cardiopulmonary function in awake swine, at rest and during graded treadmill exercise. Chronic instrumentation allows for repeated hemodynamic measurements uninfluenced by cardiodepressive anesthetic agents.

This protocol describes the surgical procedure to chronically instrument swine and the procedure to exercise swine on a motor-driven treadmill. Early ...

Repeated Measurement of Respiratory Muscle Activity and Ventilation in Mouse Models of Neuromuscular Disease

Accessory respiratory muscles help to maintain ventilation when diaphragm function is impaired. The following protocol describes a method for repeated measurements over weeks or months of accessory respiratory muscle activity while simultaneously measuring ventilation in a non-anesthetized, freely behaving mouse. The technique includes the surgical implantation of a radio transmitter and the insertion of electrode leads into the scalene and trapezius muscles to measure the electromyogram activity of these inspiratory muscles. Ventilation is measured by whole-body plethysmography, and animal movement is assessed by video and is synchronized with electromyogram activity. Measurements of muscle activity and ventilation in a mouse model of amyotrophic lateral sclerosis are presented to show how this tool can be used to investigate how respiratory muscle activity changes over time and to assess the impact of muscle activity on ventilation. The described methods can easily be adapted to measure the activity of other muscles or to assess accessory respiratory muscle activity in additional mouse models of disease or injury.

This paper introduces a method for repeated measurements of ventilation and respiratory muscle activity in a freely behaving amyotrophic lateral sclerosis (ALS) mouse model throughout disease progression with whole-body plethysmography and electromyography via an implanted telemetry device.

Accessory respiratory muscles help to maintain ventilation when diaphragm function is impaired. The following protocol describes a method for repeated ...