Burrowing behavior as an indicator of post-laparotomy pain in mice

• Published in: Frontiers in behavioral neuroscience Vol. 4; p. 165
• Main Authors: Jirkof, Paulin, Cesarovic, Nikola, Rettich, Andreas, Nicholls, Flora, Seifert, Burkhardt, Arras, Margarete
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Research Foundation 12.10.2010; Frontiers Media S.A
• Subjects: Analgesia; Analgesics; Anesthesia; Anti-inflammatory agents; Automation; Behavior; Biomedical research; Brain research; burrowing; Burrowing behavior; C57BL/6J mice; Inflammation; Laboratory animals; Laparotomy; Latency; Motivation; Neuroscience; Pain; pain assessment; Pain perception; post-laparotomy pain; post-operative pain; Surgery; Switzerland; C57BL/6J mice; post-laparotomy pain; post-surgical pain; analgesia; species-typical behavior; pain assessment; burrowing; post-operative pain
• ISSN: 1662-5153; 1662-5153
• DOI: 10.3389/fnbeh.2010.00165

Detection of persistent pain of a mild-to-moderate degree in laboratory mice is difficult because mice do not show unambiguous symptoms of pain or suffering using standard methods of short-term observational or clinical monitoring. This study investigated the potential use of burrowing performance - a spontaneous and highly motivated behavior - as a measure of post-operative pain in laboratory mice. The influence of minor surgery on burrowing was investigated in adult C57BL/6J mice of both genders in a modified rodent burrowing test (displacement of food pellets from a pellet-filled tube) within the animal's home cage. Almost all (98%) healthy mice burrowed (mean latency 1.3 h, SEM 0.5 h). After surgery without pain treatment, latency of burrowing was significantly prolonged (mean Δ latency 10 h). Analgesic treatment using the anti-inflammatory drug carprofen (5 mg/kg bodyweight) decreased latency of burrowing after surgery (mean Δ latency 5.5 h) to the level found in mice that had been anesthetized (mean Δ latency 5.4 h) or had received anesthesia and analgesia (mean Δ latency 4.6 h). Analgesia during surgery was associated with a significantly earlier onset of burrowing compared to surgery without pain treatment. A distinct gradation in burrowing performance was found ranging from the undisturbed pre-operative status to the intermediate level following anesthesia/analgesia and surgery with analgesia, to the pronounced prolongation of latency to burrow after surgery without pain relief. In conclusion, post-surgical impairment of general condition, probably mainly attributable to pain, can be conveniently assessed in laboratory mice on the basis of the burrowing test.