The authors acknowledge the work that was done by the first author of the IoN-CCI model, Bart Vos&#8224;.

Ethics statement: Animals are treated and cared for according to the guidelines of the Committee for Research and Ethical Issues of IASP11. The protocol is approved by the institutional Ethical Committee.
1. Subjects
<ol>
	<li>Use male Sprague-Dawley rats (250-300 g at arrival).</li>
	<li>House rats in solid-bottom cages in a colony room with a humidity of 40-60% and a RT of 21 &#177; 1 &#176;C.</li>
	<li>Make water and food available at libitum.</li>
	<li>Keep rats under a revers...

<ol>
	<li>Jensen, T. S., Gottrup, H., Sindrup, S. H., Bach, F. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+clinical+picture+of+neuropathic+pain.">The clinical picture of neuropathic pain.</a> Eur J Pharmacol. 429 (1-3), 1-11 (2001).</li><li>Meyer Rosberg, K., 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=Neuropathic+pain+a+multidimensional+burden+for+patients.">Neuropathic pain a multidimensional burden for patients.</a> Eur J Pain. 5 (4), 379-389 (2001).</li><li>Meyer Rosberg, K., 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=Comparison+of+the+SF+36+and+Nottingham+Health+Profile+in+patients+with+chronic+neuropathic+pain.">Comparison of the SF 36 and Nottingham Health Profile in patients with chronic neuropathic pain.</a> Eur J Pain. 5 (4), 391-403 (2001).</li><li>Vos, B. P., Strassman, A. M., Maciewicz, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Behavioral+evidence+of+trigeminal+neuropathic+pain+following+chronic+constriction+injury+to+the+rats+infraorbital+nerve.">Behavioral evidence of trigeminal neuropathic pain following chronic constriction injury to the rats infraorbital nerve.</a> J Neurosci. 14, 2708-2723 (1994).</li><li>Clavelou, P., Pajot, J., Dallel, R., Raboisson, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Application+of+the+formalin+test+to+the+study+of+orofacial+pain.">Application of the formalin test to the study of orofacial pain.</a> Neurosci Lett. 103, 349-353 (1989).</li><li>Vos, B. P., Hans, G., Adriaensen, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Behavioral+assessment+of+facial+pain+in+rats+face+grooming+patterns+after+painful+and+non-painful+sensory+disturbances+in+the+territory+of+the+rats+infraorbital+nerve.">Behavioral assessment of facial pain in rats face grooming patterns after painful and non-painful sensory disturbances in the territory of the rats infraorbital nerve.</a> Pain. 76 (1-2), 173-178 (1998).</li><li>Deseure, K. R., Adriaensen, H. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+between+two+types+of+behavioral+variables+of+non+evoked+facial+pain+after+chronic+constriction+injury+to+the+rat+infraorbital+nerve.">Comparison between two types of behavioral variables of non evoked facial pain after chronic constriction injury to the rat infraorbital nerve.</a> Comp Med. 52 (1), 44-49 (2002).</li><li>Deseure, K., Adriaensen, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nonevoked+facial+pain+in+rats+following+infraorbital+nerve+injury+a+parametric+analysis.">Nonevoked facial pain in rats following infraorbital nerve injury a parametric analysis.</a> Physiol Behav. 81 (4), 595-604 (2004).</li><li>Deseure, K., Hans, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Behavioral+study+of+non+evoked+orofacial+pain+following+different+types+of+infraorbital+nerve+injury+in+rats.">Behavioral study of non evoked orofacial pain following different types of infraorbital nerve injury in rats.</a> Physiol Behav. 138, 292-296 (2015).</li><li>Deseure, K., Koek, W., Adriaensen, H., Colpaert, F. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Continuous+administration+of+the+5+hydroxytryptamine1A+agonist+(3-Chloro-4-fluoro-phenyl)-[4-fluoro-4-[[(5-methyl-pyridin-2-ylmethyl)+-amino]-methyl]piperidin-1-yl]-methadone+(F+13640)+attenuates+allodynia+like+behavior+in+a+rat+model+of+trigeminal+neuropathic+pain.">Continuous administration of the 5 hydroxytryptamine1A agonist (3-Chloro-4-fluoro-phenyl)-[4-fluoro-4-[[(5-methyl-pyridin-2-ylmethyl) -amino]-methyl]piperidin-1-yl]-methadone (F 13640) attenuates allodynia like behavior in a rat model of trigeminal neuropathic pain.</a> J Pharmacol Exp Ther. 306 (2), 505-514 (2003).</li><li>Zimmerman, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ethical+Guidelines+for+investigations+of+experimental+pain+in+conscious+animals.">Ethical Guidelines for investigations of experimental pain in conscious animals.</a> Pain. 16, 109-110 (1983).</li><li>Mogil, J. S., Crager, S. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=What+should+we+be+measuring+in+behavioral+studies+of+chronic+pain+in+animals.">What should we be measuring in behavioral studies of chronic pain in animals.</a> Pain. 112 (1-2), 12-15 (2004).</li><li>Backonja, M. M., Stacey, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neuropathic+pain+symptoms+relative+to+overall+pain+rating.">Neuropathic pain symptoms relative to overall pain rating.</a> J Pain. 5 (9), 491-497 (2004).</li><li>Imamura, Y., Kawamoto, H., Nakanishi, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+heat+hyperalgesia+in+an+experimental+trigeminal+neuropathy+in+rats.">Characterization of heat hyperalgesia in an experimental trigeminal neuropathy in rats.</a> Exp Brain Res. 116, 97-103 (1997).</li><li>Chichorro, J. G., Zampronio, A. R., Souza, G. E., Rae, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Orofacial+cold+hyperalgesia+due+to+infraorbital+nerve+constriction+injury+in+rats+reversal+by+endothelin+receptor+antagonists+but+not+non+steroidal+anti+inflammatory+drugs.">Orofacial cold hyperalgesia due to infraorbital nerve constriction injury in rats reversal by endothelin receptor antagonists but not non steroidal anti inflammatory drugs.</a> Pain. 123 (1-2), 64-74 (2006).</li><li>Kramer, P. R., Bellinger, L. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Meal+Duration+as+a+Measure+of+Orofacial+Nociceptive+Responses+in+Rodents.">Meal Duration as a Measure of Orofacial Nociceptive Responses in Rodents.</a> J Vis Exp. (83), e50745 (2014).</li><li>Rossi, H. 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=Characterization+of+bilateral+trigeminal+constriction+injury+using+an+operant+facial+pain+assay.">Characterization of bilateral trigeminal constriction injury using an operant facial pain assay.</a> Neuroscience. 224, 294-306 (2012).</li><li>Anderson, E. 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=Use+of+the+Operant+Orofacial+Pain+Assessment+Device+(OPAD)+to+Measure+Changes+in+Nociceptive+Behavior.">Use of the Operant Orofacial Pain Assessment Device (OPAD) to Measure Changes in Nociceptive Behavior.</a> J Vis Exp. (76), 50336 (2013).</li></ol>

The most interesting aspect of the IoN-CCI model is that it provides a unique measure of spontaneous, non-evoked (neuropathic) pain. Most animal studies of neuropathic pain, using spinal nerve models, exclusively address nocifensive behaviors (e.g., vocalization and withdrawal responses), reflecting hypersensitivity to mechanical or thermal stimulations12. However, the chief clinical complaint in patients is ongoing pain, not hyperalgesia or allodynia13.
The pres...

Damage to somatosensory nerves most often leads to loss of sensation. It is not very well understood why and how, in some cases, peripheral nerve damage leads to chronic pain. As a result, painful neuropathies remain a challenging condition to treat1 and result in substantial reductions in patients&#8217; quality of life2-3. Animal models are an important tool to examine the efficacy of existing and newly developed drugs and to identify the pathophysiological mechanisms involved in the development and maintenance of neuropathic pain. Among the key challenges for translational pain research is identifying and measuring spontaneous pain in animals (i.e., physiological, behavioral or other manifestations that indicate the presence of pain in animals that are not being challenged with probing stimulations that are acutely superimposed on the subject&#8217;s basal condition). The overall goal of this procedure is to surgically induce an infraorbital nerve injury in a rat that leads to the development of both spontaneous and evoked nocifensive behavior that can used to study the mechanisms involved in trigeminal neuropathic pain and its treatment.
Directed, isolated face grooming is a unique measure of spontaneous neuropathic pain in rats. Following chronic constriction injury (CCI) of the infraorbital nerve (IoN), rats exhibit changes in spontaneous behavior and in response to tactile stimulation that are indicative of persistent pain and mechanical allodynia4. Following IoN-CCI, rats show an increased and asymmetric face grooming activity, i.e., with face wash strokes primarily directed to the nerve-injured IoN territory. In contrast to noxious stimulation of the face (e.g., formalin injection)5, non-painful sensory disturbances (i.e., unilateral vibrissae clipping, anesthetic infraorbital nerve blockade, application of mineral oil on vibrissae) did not or only very briefly (i.e., the first minutes after onset) induce a significant change in face grooming behavior6. It was concluded that this abnormal grooming after IoN-CCI is a behavioral manifestation of spontaneous, strongly aversive sensations in the injured nerve territory. This behavior in IoN-CCI rats bears strong resemblance to spontaneous pain observed in patients. Further studies have identified an important difference between face grooming behavior that is part of a more general body grooming behavior (i.e., &#8220;face grooming during body grooming&#8221;), which remains largely unaffected by IoN-CCI, and nocifensive face grooming that is neither preceded nor followed by body grooming (i.e., &#8220;isolated face grooming&#8221;), which is significantly increased after IoN-CCI7-9. Pharmacologically, face grooming during body grooming constitutes an excellent control measurement for non-specific drug effects (e.g., sedation) that may impair motor function. Movements of the forelimbs during the two types of face grooming are exactly the same.
Following IoN-CCI, rats also exhibit changes in response to tactile stimulation that are indicative of mechanical allodynia4, 10. During the first week(s) after IoN-CCI, rats no longer respond to mild or moderate tactile (i.e., von Frey) stimuli. This hyporesponsiveness is then abruptly replaced by an extreme hyperresponsiveness whereby even very weak stimulus intensities provoke nocifensive behavior. The onset of hyperresponsiveness may vary between rats, but most rats have become hyperresponsive after three to four weeks post-operative.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Chromic catgut</td>
			<td>Dynek&#160;</td>
			<td>CG504</td>
			<td></td>
		</tr>
		<tr>
			<td>Nembutal&#160; (pentobarbital)</td>
			<td>Pharmacy</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Atropine</td>
			<td>Pharmacy</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Clippers for small animals - Favorita II</td>
			<td>Aesculap</td>
			<td>GT104</td>
			<td></td>
		</tr>
		<tr>
			<td>Stereotaxic instrument</td>
			<td>Stoelting</td>
			<td>51600</td>
			<td></td>
		</tr>
		<tr>
			<td>Ophthalmic ointment (Liposic)</td>
			<td>Pharmacy</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Homeothermic monitor system</td>
			<td>Harvard Apparatus</td>
			<td>PY8 50-7221-F</td>
			<td></td>
		</tr>
		<tr>
			<td>Cotton applicator</td>
			<td>Pharmacy</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Precision cotton swab</td>
			<td>Qosina</td>
			<td>10225</td>
			<td></td>
		</tr>
		<tr>
			<td>Operation microscope</td>
			<td>Kaps</td>
			<td>SOM 62</td>
			<td></td>
		</tr>
		<tr>
			<td>Dumont #5 forceps</td>
			<td>Fine Science Tools</td>
			<td>11251-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Dumont forceps - Micro-blunted tips (#5/45)</td>
			<td>Fine Science Tools</td>
			<td>11253-25</td>
			<td></td>
		</tr>
		<tr>
			<td>Scissors - blunt tips</td>
			<td>Fine Science Tools</td>
			<td>14574-09</td>
			<td></td>
		</tr>
		<tr>
			<td>Polyester sutures - Mersilene (4-0)</td>
			<td>Ethicon</td>
			<td>R871H</td>
			<td></td>
		</tr>
		<tr>
			<td>Digital video camera</td>
			<td>Sony</td>
			<td>HDR-CX330E</td>
			<td></td>
		</tr>
		<tr>
			<td>Semmes-Weinstein Von Frey Aesthesiometer kit</td>
			<td>Stoelting</td>
			<td>58011</td>
			<td></td>
		</tr>
	</tbody>
</table>

chronic constriction injury of the rat's infraorbital nerve (ion-cci) to study trigeminal neuropathic pain

Animal models are important tools to study the pathophysiology and pharmacology of neuropathic pain. This manuscript describes the surgical and behavioral procedures to study trigeminal neuropathic pain in rats. To meet the specificity of trigeminal neuropathic pain syndromes, the infraorbital nerve (IoN) is subjected to a chronic constriction injury (CCI) by loosely ligating the nerve. An intra-orbital approach is presented here to expose and ligate the IoN in the orbital cavity. After IoN ligation, rats exhibit changes in spontaneous behavior and in response to von Frey hair stimulation that are indicative of persistent pain and mechanical allodynia. Two phases can be defined in the development of the behavioral changes. During the first week following IoN-CCI (phase 1), rats show an increased and asymmetric face grooming activity, i.e., with face wash strokes primarily directed to the nerve-injured IoN territory. A distinction is made between face grooming behavior that is part of a more general body grooming behavior, which remains largely unaffected by IoN-CCI, and face grooming that is neither preceded nor followed by body grooming, which is significantly increased after IoN-CCI. During this period, responsiveness to mechanical stimulation of the IoN territory is reduced. This hyporesponsiveness is abruptly replaced by an extreme hyperresponsiveness whereby even very weak stimulus intensities provoke nocifensive behavior (phase 2). The phenomenological similarities between these behavioral alterations and reported signs of facial pain (i.e., responses to noxious stimulation of the face) suggest the presence of dysesthesia/paresthesia and mechanical allodynia in the ligated IoN territory.

IoN-CCI rats show a strong post-operative increase in the amount of time spent on isolated face grooming (Figure 1). The increase peaks at the end of the first post-operative week and then declines during the following weeks. Most recent studies have found face grooming to be significantly increased for up to three weeks. Face grooming behavior in sham operated rats is more or less unaffected.
IoN-CCI rats also show an almost complete lack of responsiveness to ipsilateral mech...

Watch this Scientific Journal Video about Chronic Constriction Injury of the Rat's Infraorbital Nerve IoN-CCI to Study Trigeminal Neuropathic Pain at JoVE.com

Chronic Constriction Injury of the Rat&#039;s Infraorbital Nerve IoN-CCI to Study Trigeminal Neuropathic Pain

This manuscript describes a rodent model to study trigeminal neuropathic pain. The methods described include surgical procedures to perform a chronic constriction injury of the rat&#8217;s infraorbital nerve and the post-surgical behavioral tests to measure the changes in spontaneous and evoked behavior that are indicative of persistent pain and allodynia.

Chronic Constriction Injury of the Rat's Infraorbital Nerve (IoN-CCI) to Study Trigeminal Neuropathic Pain

Animal models are important tools to study the pathophysiology and pharmacology of neuropathic pain. This manuscript describes the surgical and behavioral ...

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19.1K vistas.  University of Antwerp. This manuscript describes a rodent model to study trigeminal neuropathic pain. The methods described include surgical procedures to perform a chronic constriction injury of the rat’s infraorbital nerve and the post-surgical behavioral tests to measure the changes in spontaneous and evoked behavior that are indicative of persistent pain and allodynia. 