title: Validation of a Behavioral Ethogram for Assessing Postoperative Pain in Guinea Pigs (Cavia porcellus).
abstract: Although guinea pigs (Cavia porcellus) have been used in research for more than a century and remain the most prevalent USDA-covered species, little has been elucidated regarding the recognition of clinical pain or analgesic efficacy in this species. We sought to assess pain in guinea pigs by using newer, clinically relevant methods that have been validated in other rodent species: the behavioral ethogram and cageside proxy indicator. In this study, 10 male guinea pigs underwent electronic von Frey testing of nociception, remote videorecording of behavior, and cageside assessment by using time-to-consumption (TTC) of a preferred treat test. These assessments were performed across 2 conditions (anesthesia only and castration surgery under anesthesia) at 3 time points (2, 8, and 24 h after the event). The anesthesia only condition served to control for the nonpainful but potentially distressing components of the surgical experience. Compared with those after anesthesia only conditions, subtle body movements were increased and nociceptive thresholds were decreased at 2 and 8 h after surgery. At 24 h, neither subtle body movement behaviors nor nociceptive thresholds differed between the 2 conditions. In contrast, TTC scores did not differ between the anesthesia only and surgery conditions at any time point, underscoring the challenge of identifying pain in this species through cageside evaluation. By comparing ethogram scores with measures of nociception, we validated select behaviors as pain-specific. Therefore, our novel ethogram allowed us to assess postoperative pain and may further serve as a platform for future analgesia efficacy studies in guinea pigs.
authors.affiliation: Refinement and Enrichment Advancements Laboratory (REAL), Unit for Laboratory Animal Medicine (ULAM), University of Michigan, Ann Arbor, Michigan.
authors.forename: Misha L
authors.initials: ML
authors.lastname: Dunbar
authors.affiliation: Refinement and Enrichment Advancements Laboratory (REAL), Unit for Laboratory Animal Medicine (ULAM), University of Michigan, Ann Arbor, Michigan.
authors.forename: Emily M
authors.initials: EM
authors.lastname: David
authors.affiliation: Refinement and Enrichment Advancements Laboratory (REAL), Unit for Laboratory Animal Medicine (ULAM), University of Michigan, Ann Arbor, Michigan.
authors.forename: Marian R
authors.initials: MR
authors.lastname: Aline
authors.affiliation: Refinement and Enrichment Advancements Laboratory (REAL), Unit for Laboratory Animal Medicine (ULAM), University of Michigan, Ann Arbor, Michigan;, Email: jlofgren@umich.edu.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Lofgren
mesh_terms: D000698:Analgesia; D000700:Analgesics / Q000494:pharmacology*; D000758:Anesthesia; D000818:Animals; D001522:Behavior, Animal; D006168:Guinea Pigs; D008297:Male; D010147:Pain Measurement / Q000379:methods / Q000662:veterinary*; D010149:Postoperative Pain / Q000517:prevention & control / Q000662:veterinary*
chemical_list: D000700:Analgesics
references.citation: PLoS One. 2012;7(4):e35656
references.pmid: 22558191
references.citation: Eur J Pain. 2003;7(5):397-406
references.pmid: 12935791
references.citation: Aust Vet J. 2010 Mar;88(3):67-74
references.pmid: 20402687
references.citation: Pharmacol Biochem Behav. 2007 Aug-Sep;87(3):349-59
references.pmid: 17583780
references.citation: J Am Vet Med Assoc. 2010 Aug 15;237(4):395-401
references.pmid: 20707749
references.citation: J Pain Res. 2012;5:391-400
references.pmid: 23091396
references.citation: J Am Assoc Lab Anim Sci. 2012 Jan;51(1):42-9
references.pmid: 22330867
references.citation: Physiol Behav. 1994 Apr;55(4):651-7
references.pmid: 8190790
references.citation: Res Vet Sci. 2009 Oct;87(2):336-47
references.pmid: 19303122
references.citation: Lab Anim. 2013 Jul;47(3):153-61
references.pmid: 23563122
references.citation: Lab Anim. 2009 Jan;43(1):17-26
references.pmid: 19015177
references.citation: Pain. 2001 Feb 1;90(1-2):65-74
references.pmid: 11166971
references.citation: PLoS One. 2012;7(9):e44437
references.pmid: 22970216
references.citation: Lab Anim. 1996 Jan;30(1):13-21
references.pmid: 8709568
references.citation: Mol Pain. 2011;7:55
references.pmid: 21801409
references.citation: Behav Pharmacol. 2004 Nov;15(7):461-72
references.pmid: 15472568
references.citation: Front Behav Neurosci. 2010 Oct 12;4:165
references.pmid: 21031028
references.citation: Nat Methods. 2010 Jun;7(6):447-9
references.pmid: 20453868
references.citation: PLoS One. 2011;6(3):e13347
references.pmid: 21423605
references.citation: J Am Assoc Lab Anim Sci. 2014 Jan;53(1):24-8
references.pmid: 24411776
references.citation: PLoS One. 2013;8(9):e75948
references.pmid: 24098748