Electrophysiological study for comparing the effect of biological activity between type A botulinum toxins in rat gastrocnemius muscle

Abstract

Background: New cosmetic applications and products based on the effects of botulinum toxin (BTX) treatment have stimulated demand for this class of natural compounds. This demand generates the need for appropriate standardized protocols to test and compare the effectiveness of new BTX preparations.

Objectives: Based on the previously described electrophysiological methods, we measured and compared the inhibitory effects of two BTX type A (BTX-A) preparations on neuromuscular transmission through split-body test.

Methods: The effectiveness was evaluated in terms of the compound muscle action potential (CMAP) and conduction velocity after BTX-A injection. We used a split-body method to compare two different BTX-As in the rat.

Results: Based on the changes in the CMAP, the two different BTX-As induced paralytic effect on the rat tibialis anterior muscle. However, the two different BTX-A preparations did not differ significantly in effectiveness and did not induce a delay in conduction velocity.

Conclusions: The new BTX-A preparation used in this electrophysiological study had similar effect compared with the previously marketed BTX-A.[AQ: Please approve the edits made to the sentence "The new BTX-A preparation…") We propose that a split-body electrophysiological protocol will be useful in establishing the comparative effectiveness of new BTX products.

Keywords: Botulinum toxin; compound muscle action potential; toxicity assay.