Acute and Chronic Effects of Botulinum Toxin Type-A on the structure and Function of the Quadriceps Femoris Muscles of New Zealand White Rabbits
Date
2015-10-01
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Botulinum toxin type-A (BTX-A) injections have become a common treatment modality for a
variety of neuromuscular disorders with the primary aim to relax spastic muscles, for example, in
children with cerebral palsy, or following a stroke. Once injected, BTX-A prevents acetylcholine
release at the motor nerve endings, thereby producing a dose-dependent muscle paralysis.
Despite an exponential growth of patients receiving BTX-A treatment, there has been no
systematic evaluation of the effects of the toxin on target and non-target muscles. Therefore, the
general purpose of this PhD project was to evaluate muscle mass, strength, and contractile
material in injected and contralateral non-injected quadriceps muscles of New Zealand White
(NZW) rabbits following single and repeated BTX-A injections. Muscle mass was assessed as
the wet weight of muscles following sacrifice, strength was assessed by stimulating the knee
extensor muscles via femoral nerve stimulation and quantifying the knee extensor force, the
amount of contractile material was quantified histologically.
We found that six-monthly BTX-A injections into the quadriceps caused substantial muscle
weakness, atrophy, and contractile material loss in the injected and the contralateral non-injected
muscles. Adding direct electrical muscle stimulation during the BTX-A injection help to
alleviate muscle mass, strength and contractile material loss and the injected and contralateralnon
injected muscles, and finally, BTX-A injections had long lasting effects that were not fully
recovered at six months following the end of the injection protocol.
We concluded from the results of this series of studies that BTX-A treatment resulted in adverse
effects on the injected and contralateral non-injected musculature up to six months following the
iii
injection protocol. Future studies should be aimed at identifying strategies that minimize/prevent
adverse effects of BTX-A injections on target and non-target muscles.
Description
Keywords
Anatomy, Physiology
Citation
Fortuna, R. (2015). Acute and Chronic Effects of Botulinum Toxin Type-A on the structure and Function of the Quadriceps Femoris Muscles of New Zealand White Rabbits (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/24695