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[Effect of botulinum toxin type A injection into the masseter muscle on mandibular development in rats]
Jin-Jun Huang1, Da-Lie Liu, Bing Chen
1Department of Plastic Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China.
Objective:
To investigate the effect of Botulinum toxin type A (Botox) injection into the masseter muscle on mandibular development in rats.
Methods:
12 28-day-old Wistar rats were divided into two groups as Botox group (n= 6) and control group (n = 6) which received anesthesia only. In Botox group, Botox was injected into the right masseter muscle, while only sterile saline into the left muscle. When the rats were 75-day-old, CT scan and 3D reconstruction were performed for cephalometry. The masseter muscles at both sides were weighed. Histologic study of masseter muscle and mandible was also performed.
Results:
The weight of right masseter muscle was (0.4575 +/- 0.0940) g in Botox group, and (0.8899 +/- 0.1030) g in control group (< 0.05). The mandibular height II and III was (10.8 +/- 0.8) mm and (9.5 +/- 0.6) mm in Botox group and (12.5 +/- 0.6) mm and (10.7 +/- 0.4) mm in control group, respectively (P < 0.05). The intergonial distance was (11.6 +/- 0.6) mm and (12.4 +/- 0. 6) mm in Botox and control group, respectively (P > 0.05).
Conclusions:
When the rats receive Botox injection into the masseter muscle at young age, the grown-up rats have a decreased mandibular height, but the mandibular length and intergonial distance are not affected.
