Premium
A novel rat model of orthopedic trauma for prehospital pain studies
Author(s) -
Xiang Lusha,
Avila Martha M,
Klemcke Harold G,
Ryan Kathy L,
HinojosaLaborde Carmen
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.1087.10
Subject(s) - medicine , orthopedic surgery , soft tissue injury , anesthesia , ketamine , femur fracture , tibia fracture , tibia , soft tissue , hyperalgesia , surgery , nerve injury , femur , nociception , receptor
Animal models of orthopedic trauma usually consist of tibia or femur fractures that require a post‐fracture fixation surgery. Such an approach compromises subsequent assessments of pain following orthopedic trauma. The goal of the current study was to establish a rat model of long bone fracture that needs no post‐trauma surgeries, thereby optimizing its utility for future studies especially with prehospital pain management. Orthopedic trauma, including soft tissue injury and fibula fracture, was performed on the right hindlimb in Sprague Dawley rats. Soft tissue injury was induced in anesthetized rats via clamping the retrofemoral tissue groups for 30 sec, followed by closed fibula fracture using a 15‐gauge needle. Thermal hyperalgesia (paw withdrawal time, PW, n = 24), mechanical allodynia (mechanical threshold, MT, n = 17), weight‐bearing ratio (right/left, WB, n = 12), and tail flick latency (n = 10) were determined before and 90 minutes after the injury. Rats were then treated with 5 mg/kg ketamine or vehicle (saline) through jugular catheters, and nociceptive measurements were repeated at 10, 40, 80, and 120 minutes after injection. Trauma had no effect on tail flick responses but decreased PW, MT, and WB ( Table 1). Ketamine increased PW, WB, and tail flick latency mainly within the first 40 minutes following injection ( Figure 1). As no post‐trauma surgery is required, our data suggest that this trauma model may be ideal for prehospital pain research. To our knowledge, this is the first study to show that 5 mg/kg of ketamine iv could be considered for instant analgesia in rats. 1 Thermal hyperalgesia (PW), mechanical allodynia (MT), weight‐bearing ratio (WB), and tail flick response before and after trauma.PW (second) MT (gram) WB (right/left) Tail flick (second)Basal 11.3±0.5 40.5±1.5 1.0±0.1 5.6±0.2Trauma 6.5±0.2 * 31.7±2.3 * 0.5±0.1 * 5.6±0.1* P < 0.05 trauma vs. basal.