成鼠咬肌活性降低後對顱顏骨骼之影響

過去探討咀嚼肌對顱顏型態影響的研究多是針對發育成長中個體，缺少發育成熟個體的基礎研究。而現今已有許多關於肉毒桿菌素注射應用於一般醫學，成人美容的臨床研究；臨床上，肉毒桿菌素更多是使用在成人身上。相對於臨床上肉毒桿菌素的使用，在已發育成熟個體的基礎研究仍然有其必要性。因此，本實驗以肉毒桿菌神經毒素A型(Botox®, Allergan Inc.,Irvine, OCA, USA)注射成熟大白鼠之咬肌，造成萎縮，降低咬合功能，藉此觀察其對於老鼠顱顏部肌肉造成的差異，對頭顱骨骼型態及骨質的影響、以及皮質骨厚度及海綿骨結構的改變的比較。此實驗種所採取的研究方式為：選取10隻8週大的大鼠SD (Sprague-Dawley) rat，於大鼠的左側咬肌注射肉毒桿菌素，右側咬肌注射等量生理食鹽水，另選10隻8週大的大鼠SD (Sprague-Dawley) rat 左右側均不注射任何藥物做為對照組。兩組給予相同飲水與飼料，飼養90天後犧牲，取下咬肌測量其重量，將大鼠頭顱骨製作成乾燥頭顱骨(dry skull)，以電子游標尺(brand)直接量測，並對頭顱骨與下顎骨以「雙能量X光吸收儀」（Dual-energy X-ray absorptiometry, DEXA）進行骨質(Bone Mineral Content)掃描，所得到的結果進行實驗組右兩側及實驗組對照組之間之比較。另外，於所有樣本之下顎骨選取二處製作骨磨片標本，觀察兩組之間皮質骨(cortical bone)厚度及海綿骨結構的差異。結果發現九十天內，大鼠之平均體重變化無明顯差距，最後的體重也無統計上的差異。在咬肌濕測的部分，實驗組左側(注射肉毒桿菌, 1.13±0.22g)較實驗組右側(注射生理食鹽水, 2.12±0.23g)小，且有統計上的差異；而實驗組注射生理食鹽水和對照組(2.26±0.30g)之間並沒有明顯不同。乾燥頭顱骨測量中，共有11項具有統計上的意義，分別為(1)頭顱項測量項目中，實驗組之Interzygomatic width, Lower anterior facial height(2)上顎項測量項目中，實驗組之U6 height(3)下顎項測量項目中，實驗組之Mandibular length I(Cond-L1i), Corpus length(Id-Go), Mandibular plane angle(Go-Gn), Mandibular length VI (ZAI-Mn), Mandibular height (CorN-Gn), Ramus height I(Cond-Gn), L1 crown height, L6 height。至於實驗組右側(注射生理食鹽水)和對照組之比較，則在各項目間均無統計上的有意義的差異。骨質量測量部分實驗組與對照組相比顯著較低，但實驗組左右比較亦有明顯差異。皮質骨厚度和海綿骨結構部分的部分，實驗組左側(注射肉毒桿菌)均較實驗組右側(注射生理食鹽水)有明顯變小，而實驗組注射生理食鹽水和對照組之間並沒有明顯不同。本實驗研究結果顯示，在成鼠咬肌萎縮後會造成顱顏骨骼型態和內部結構的改變。

關鍵字

成鼠；咬肌活性；顱顏骨骼

並列摘要

The purpose of this study is to evaluate the effects of reduced masticatory muscle activity on the craniofacial bone of adult rats. In this study, Botulinum Neurotoxin type A (BTX-A)was injected to reduce adult rats’ masticatory muscle function and the change of craniofacial bony structure was investigated Method: 20 male Sprague-Dawley rats, body weight about 300 grams and 60 days after birth. The rats were randomly divided into 2 groups, 10 rats per group. Group I: L’t side: 25U/ml (0.3 ml) Botox in masseter muscle. R’t side: equal amount of sterilized saline in masseter muscle. Group II (control group): no drug/saline was given. After 90 days, the rats were sacrificed and the weight of masseter muscle was measured; direct anthropometric measurements of skull and mandible, cortical thickness and trabecular thickness and BMC (scanned with DEXA) measurements of skull and mandible were observed. All measurements were calculated and compared statistically. Result: Significant changes in muscle weight and anthropometric measurement in Botox treatment side, such as decreased ramus height, increased gonial angle, increased teeth crown height. The results for the vertical measurements were the most significant of all. Decreased cortical thickness and trabecular thickness were seen on the paralyzed side. BMC value also showed significant difference between both sides. Compare to control group, lower BMC value in the experimental group was seen. According to the results, reduced masticatory function in the adult rats affects not only the weight of muscle, but also the craniofacial bony structure, dental pattern and the internal bony structure.

並列關鍵字

adult rats ； masticatory muscle activity ； craniofacial bone

參考文獻

Aoki KR (2001). A comparison of the safety margins of botulinum neurotoxin serotypes A, B, and F in mice. Toxicon 39(12):1815-20.

Bianchi ML, Mazzanti A, Galbiati E, Saraifoger S, Dubini A, Cornelio F, et al. (2003). Bone mineral density and bone metabolism in Duchenne muscular dystrophy. Osteoporos Int 14(9):761-7.

Billante CR, Zealear DL, Billante M, Reyes JH, Sant'Anna G, Rodriguez R, et al. (2002). Comparison of neuromuscular blockade and recovery with botulinum toxins A and F. Muscle Nerve 26(3):395-403.

Borodic GE, Ferrante R, Pearce LB, Smith K (1994). Histologic assessment of dose-related diffusion and muscle fiber response after therapeutic botulinum A toxin injections. Mov Disord 9(1):31-9.

Bouvier M, Hylander WL (1984). The effect of dietary consistency on gross and histologic morphology in the craniofacial region of young rats. Am J Anat 170(1):117-26.

國際替代計量

成鼠咬肌活性降低後對顱顏骨骼之影響

未授權

主題瀏覽