engleski

Antinociceptive profile of botulinum toxin type A in rat models of pain and inflammation

This study was designed to investigate the antinociceptive profile of botulinum toxin type A (BTX-A) using different animal models of pain and inflammation. Over the last 20 years BTX-A has been used for treating a variety of disorders characterized by increased muscle contraction. Recently, there has been an increase of BTX-A usage in the treatment of various pain syndromes. However, assumptions in what type of pain is BTX-A effective, what doses are effective, how long the effect does last are currently only derived from small clinical trials or individual experience. Peripheral administration of formalin, capsaicin and carrageenan solutions was used to provoke acute pain states associated with inflammation. Peripheral neuropathic pain was evoked by partial sciatic nerve transection. As a model of experimental postsurgical pain, gastrocnemius muscle was incised. Pain of musculoskeletal origin was made by low pH saline injection. The results of present experiments show that peripherally administered BTX-A produces analgesic effect in second phase of formalin test that seems not to be dose-dependent. The analgesic effect becomes significant on day 5 following toxin’ s application in the rat paw pad and lasts for 30 days. BTX-A has also been effective in other two models of inflammatory pain as well as in models of chronic pain states, including the diabetic neuropathy. In all models, peripherally administered BTX-A reduces the mechanical and thermal hyperalgesia. This study, for the first time, demonstrated the efficacy of BTX-A on the neural component of pain associated with inflammation in various experimental pain conditions. In conclusion, these observations suggest that BTX-A might be effective in different pain syndromes, probably of neural origin with an inflammatory component.

botulinum toxin; pain; nociception

DOI: 10.1111/j.1472-8206.2004.00260.x