J Korean Acad Rehabil Med.  2008 Feb;32(1):1-8.

Antinociceptive Effect of Botulinum Toxin A in Persistent Muscle Pain Rat Model

Affiliations
  • 1Mirae Rehabilitation Medicine Clinic, Korea.
  • 2Institute for Brain Research, Department of Rehabilitation Medicine, College of Medicine, Chungnam National University, Korea. mksohn@cnu.ac.kr
  • 3Department of Rehabilitation Medicine, The First Clinical College of Harbin Medical University, China.

Abstract


OBJECTIVE
To investigate the effects of botulinum toxin on the mechanical hyperalgesia, electrophysiology and motor functions in the persistent muscle pain rat model. METHOD: A secondary mechanical hyperalgesia in the bilateral hindpaws of Sprague-Dawley rats was produced by the repeated injections of acidic saline into gastrocnemius. Botulinum toxin A (BTX-A(4): 4 U/kg, BTX-A(7): 7 U/kg) was administrated into same muscle 24 hours after a second injection of saline. The mechanical hyperalgesia was measured with withdrawal threshold to von Frey filament. The grade of muscle paralysis was evaluated with electrophysiology and the locomotor performance using inclined plane board.
RESULTS
The mechanical hyperalgesia was significantly decreased from 5 days to 2 weeks in BTX-A(7) group in the injected side. The dose-dependent decreased amplitude of compound muscle action potential and reduced prevalence of endplate noise from the first day of botulinum toxin injection lasted for 4 weeks in both gastrocnemius. The maximum angle maintained at initial position on the inclined plane board did not change.
CONCLUSION
Local muscular injection of botulinum toxin A reduced ipsilateral hyperalgesia dose-dependently in persistent muscle pain rat model without motor deficit. The antinociceptive mechanism of botulinum toxin might act at a local or peripheral rather than a systemic or central effect due to ineffectiveness of contralateral hyperalgesia. Clinically, botulinum toxin A might be useful for the treatment of local and referred pain of muscle origins.

Keyword

Persistent muscle pain; Botulinum toxin; Rat model

MeSH Terms

Action Potentials
Animals
Botulinum Toxins
Electrophysiology
Hyperalgesia
Muscles
Noise
Pain, Referred
Paralysis
Prevalence
Rats
Rats, Sprague-Dawley
Botulinum Toxins
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