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Chronic Post-Ischemia Pain Model for Complex Regional Pain Syndrome Type-I in Rats
Published on: January 21, 2020
Two-week cast immobilization induced chronic widespread hyperalgesia in rats
1Multidisciplinary Pain Center, Aichi Medical University, Nagakute, Aichi, 480-1195, Japan.
European Journal of Pain (London, England)
|February 17, 2012
Summary
Physical immobilization can lead to chronic pain. This study developed a rat model for chronic post-cast pain (CPCP), revealing that free radicals from immobilization-induced injury contribute to widespread pain sensitivity.
Area of Science:
- Pain Research
- Neuroscience
- Surgical Recovery
Background:
- Physical immobilization is linked to chronic pain development after trauma or surgery.
- Mechanisms underlying sustained immobilization-induced chronic pain are not well understood.
Purpose of the Study:
- To develop a rat model for chronic post-cast pain (CPCP).
- To elucidate the underlying mechanisms of CPCP.
Main Methods:
- Hindlimb immobilization in rats for 2 weeks, followed by 10 weeks of remobilization.
- Assessment of pain behaviors, muscle atrophy, and inflammatory changes.
- Sciatic nerve block and administration of free radical scavengers to investigate pain mechanisms.
Main Results:
- Cast immobilization induced muscle atrophy and inflammation post-removal.
- CPCP rats exhibited spontaneous pain behaviors and widespread mechanical hyperalgesia for up to 10 weeks.
- Hyperalgesia was linked to sensory input from the immobilized limb and involved oxygen free radicals.
Conclusions:
- Cast immobilization can induce chronic pain and widespread hyperalgesia in a rat model.
- Ischemia/reperfusion injury and subsequent oxygen free radical production are implicated in CPCP.
- This model provides insights into the mechanisms of chronic pain following immobilization.
