Botulinum toxin type-A effect as a preemptive treatment in a model of acute trigeminal pain: a pre-clinical double-blind and placebo-controlled study

Arq Neuropsiquiatr. 2011 Feb;69(1):56-63. doi: 10.1590/s0004-282x2011000100012.

Abstract

The purpose of this study was to investigate if botulinum neurotoxin type-A (BoNT/A) had a preemptive antinociceptive effect in a formalin-induced orofacial pain model (FT). To test this hypothesis, male Rattus norvegicus were injected with isotonic saline solution 0.9% or BoNT/A administered as a 40 μl bolus, lateral to their nose, at 24 hours, 8, 15, 22, 29 or 36 days pre-FT. The procedures were repeated 42 days later. Influence on motor activity was assessed through the open-field test. Pain scores corresponded to the time spent rubbing and flicking the injected area. Animals pre-treated with BoNT/A at the first protocol (8 days subgroup) showed reduced inflammatory scores (p=0.011). For the other groups no significant results were observed at any phase. Motor activity was similar in both groups. BoNT/A showed to be effective preventing inflammatory pain up to eight days after the first treatment, an effect not reproduced on the second dose administration.

MeSH terms

  • Acute Disease
  • Animals
  • Botulinum Toxins, Type A / administration & dosage*
  • Double-Blind Method
  • Facial Pain / prevention & control
  • Isotonic Solutions / administration & dosage
  • Male
  • Pain Measurement / methods
  • Placebos
  • Random Allocation
  • Rats
  • Sodium Chloride / administration & dosage
  • Trigeminal Neuralgia / prevention & control*

Substances

  • Isotonic Solutions
  • Placebos
  • Sodium Chloride
  • Botulinum Toxins, Type A