Division of Orthodontics, University of Connecticut Health Center, Farmington, Conn.
Division of Orthodontics, University of Connecticut Health Center, Farmington, Conn.
Am J Orthod Dentofacial Orthop. 2019 Aug;156(2):193-202. doi: 10.1016/j.ajodo.2018.08.023.
To evaluate whether the effects on the mandibular condylar cartilage (MCC) and subchondral bone are transient of botulinum neurotoxin (Botox) injection into the masseter muscle.
Botox (0.3 U) was injected into the right masseter of 6-week-old female mice (C57BL/6; n = 16). In addition, 16 mice were used as control and received no injections. Experimental and matching control mice were killed 4 or 8 weeks after the single Botox injection. Mandibles and mandibular condyles were analyzed by means of microscopic computed tomography (microCT) and histology. Sagittal sections of condyles were stained for tartrate-resistant acid phosphatase (TRAP), toluidine blue, 5-ethynyl-2'-deoxyuridine (EdU), and terminal deoxynucleotide transferase-mediated dUTP nick-end labeling.
Bone volume fraction was significantly decreased on the subchondral bone of the Botox-injected side, compared with the control side and control mice, 4 and 8 weeks after injection. Furthermore, histologic analysis revealed decrease in mineralization, cartilage thickness, TRAP activity, and EdU-positive cells in the MCC of the Botox-injected side 4 and 8 weeks after injection.
The effects on the MCC and subchondral bone of Botox injection into the masseter muscle persisted for 8 weeks after injection and were not considered to be transient.
评估肉毒毒素（Botox）注射到咬肌中对下颌髁状突软骨（MCC）和软骨下骨的影响是否是短暂的。
将 Botox（0.3U）注射到 6 周龄雌性小鼠（C57BL/6；n=16）右侧咬肌中。此外，16 只小鼠作为对照，未接受注射。在单次 Botox 注射后 4 或 8 周，处死实验和匹配的对照小鼠。通过微观计算机断层扫描（microCT）和组织学分析下颌骨和下颌髁。髁突的矢状切片用抗酒石酸酸性磷酸酶（TRAP）、甲苯胺蓝、5-乙炔基-2'-脱氧尿苷（EdU）和末端脱氧核苷酸转移酶介导的 dUTP 缺口末端标记染色。
与对照侧和对照小鼠相比，注射后 4 和 8 周，Botox 注射侧的软骨下骨骨体积分数明显降低。此外，组织学分析显示，注射后 4 和 8 周，Botox 注射侧的 MCC 矿化、软骨厚度、TRAP 活性和 EdU 阳性细胞减少。
肉毒毒素注射到咬肌中对 MCC 和软骨下骨的影响持续 8 周，而不是短暂的。
