Growth effects of botulinum toxin type A injected unilaterally into the masseter muscle of developing rats

• Published in: Journal of Zhejiang University. B. Science Vol. 16; no. 1; pp. 46 - 51
• Main Authors: Park, Chanyoung, Park, Kitae, Kim, Jiyeon
• Format: Journal Article
• Language: English
• Published: Hangzhou Zhejiang University Press 2015; Springer Nature B.V
• Subjects: Animals; Biomedical and Life Sciences; Biomedicine; Body Weight; botulinum toxin; Botulinum Toxins, Type A - administration & dosage; Botulinum Toxins, Type A - chemistry; China; Injections, Intramuscular; Male; Mandible - physiopathology; Masseter Muscle - drug effects; Masseter Muscle - metabolism; Muscle Contraction - drug effects; muscles; Rats; Rats, Sprague-Dawley; skeletal development; skull; China; Craniofacial growth; Mandible; 颅面生长; 肉毒毒素; Botulinum toxin; R782.2; 下颌骨
• ISSN: 1673-1581; 1862-1783; 1862-1783
• DOI: 10.1631/jzus.B1400192

Objective： To evaluate the effects of botulinum toxin type A （BTX-A） on mandible skeletal development by inducing muscle hypofunction. Methods： Four-week-old Sprague-Dawley rats （n=60） were divided into three groups： Group 1 animals served as controls and were injected with saline; Group 2 animals were injected unilaterally with BTX-A （the contralateral side was injected with saline）; and Group 3 animals were injected bilaterally with BTX-A. In Group 2, the saline-injected side was designated the control side （Group 2-1）, whereas the BTX-A-injected side was designated the experimental side （Group 2-2）. After four weeks, the animals were sacrificed, dry skulls were prepared, and mandibles were measured. Results： In the unilateral group, the experimental side （Group 2-2） had reduced di- mensions for all mandible measurements compared with the control side （Group 2-1）, suggesting a local effect of BTX-A on mandible growth, likely due to muscle reduction. Conclusions： Localized BTX-A injection induced a change in craniofacial growth, and the skeletal effect was unilateral despite both sides of the mandible functioning as one unit.