Acute and Chronic Effects of Botulinum Toxin Type-A on the structure and Function of the Quadriceps Femoris Muscles of New Zealand White Rabbits

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.

Name thesis:degree_name

Doctor of Philosophy (PhD)

Grantor dc:publisher.institution

Graduate Studies

Year dc:date.issued

2015

Author dc:creator

• Fortuna, Rafael

Advisor dc:contributor.advisor

• Herzog, Walter

• Anatomy
• Physiology

Statement dc:rights

• University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.

Language dc:language.iso

eng

DOI

http://dx.doi.org/10.11575/PRISM/24695

OAI identifier oai:identifier

oai:ucalgary.scholaris.ca:11023/2581