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Chronic Post-Ischemia Pain Model for Complex Regional Pain Syndrome Type-I in Rats
Published on: January 21, 2020
Persistent deep mechanical hyperalgesia induced by repeated cold stress in rats
Teruaki Nasu1, Toru Taguchi, Kazue Mizumura
1Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan.
European Journal of Pain (London, England)
|June 30, 2009
Summary
Repeated cold stress (RCS) in mice effectively models chronic muscle pain. This stress method induces long-lasting deep muscle hyperalgesia, offering a new avenue for studying pain mechanisms and treatments.
Area of Science:
- Pain research
- Animal models
- Stress physiology
Background:
- Chronic muscle pain, particularly in the neck, shoulder, and low back, is prevalent and often linked to stress.
- Developing reliable animal models is crucial for understanding the mechanisms of chronic pain and testing potential therapies.
Purpose of the Study:
- To establish a model of long-lasting muscle mechanical hyperalgesia using repeated cold stress (RCS).
- To validate a method for measuring deep muscle mechanical nociceptive thresholds.
- To investigate the effects of different intensities of RCS on pain chronicity and severity.
Main Methods:
- Validated a deep mechanical withdrawal threshold measurement technique using a Randall-Selitto analgesiometer with surface skin anesthesia.
- Exposed mice to repeated cold stress (RCS) by alternating temperatures between 22°C and 4°C or -3°C.
- Administered intramuscular lidocaine to confirm muscle hyperalgesia.
Main Results:
- RCS at 4°C for 5 days induced bilateral deep mechanical hyperalgesia lasting 2-3 weeks without skin hyperalgesia.
- RCS at -3°C resulted in more severe and longer-lasting (approx. 6 weeks) deep mechanical hyperalgesia, accompanied by cutaneous hyperalgesia.
- Lidocaine injections confirmed the muscle tissue itself was hyperalgesic.
Conclusions:
- Repeated cold stress (RCS) provides a viable model for inducing chronic muscle pain and mechanical hyperalgesia in mice.
- The intensity of cold stress correlates with the duration and severity of induced muscle hyperalgesia.
- This RCS model holds promise for future research into the mechanisms and treatments of chronic muscle pain.
