Manopinivate Atith, Kaneko Sawa, Soma Kunimichi
Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, Japan.
J Med Dent Sci. 2006 Mar;53(1):67-74.
The importance of masticatory muscle function on the growth and differentiation of condyle was examined. The aim of this study was to investigate how reduced masticatory muscle function influences intrinsic regulatory factors which govern growth and differentiation of condylar cartilage. Masseter muscles of 3-week-old Wistar rats were resected bilaterally. Masseteric resected animals and corresponding control animals were sacrificed at 3, 6, 12 and 21 days post-resection. The condyles were then processed for histological and immunohistochemical analysis. The expression patterns of an inhibitory regulator (IL-1beta) and a master regulator (Sox9) of chondrogenesis in condylar cartilage of growing rats were investigated. Quantitative analysis shows that masseteric resection significantly increased the number of IL-1beta positive cells in proliferative layer. In contrast, the number of Sox9 positive cells was significantly decreased compared to the control animals. It can be concluded that the reduced articular function due to masseteric resection decreased condylar cartilage cell differentiation which led to the decrease in the thickness of condylar cartilage.
研究了咀嚼肌功能对髁突生长和分化的重要性。本研究的目的是探讨咀嚼肌功能降低如何影响控制髁突软骨生长和分化的内在调节因子。对3周龄Wistar大鼠双侧切除咬肌。咬肌切除的动物和相应的对照动物在切除后3、6、12和21天处死。然后对髁突进行组织学和免疫组织化学分析。研究了生长中大鼠髁突软骨中软骨形成的抑制调节因子（IL-1β）和主要调节因子（Sox9）的表达模式。定量分析表明，咬肌切除显著增加了增殖层中IL-1β阳性细胞的数量。相比之下，与对照动物相比，Sox9阳性细胞的数量显著减少。可以得出结论，咬肌切除导致的关节功能降低会降低髁突软骨细胞的分化，从而导致髁突软骨厚度的减小。
