Rabie A B M, Xiong H, Hägg U
Orthodontics, Faculty of Dentistry, The University of Hong Kong, China.
Eur J Orthod. 2004 Aug;26(4):353-8. doi: 10.1093/ejo/26.4.353.
The aim of this investigation was to assess quantitatively the adaptive changes in the condyles of adult rats to forward mandibular positioning. The level of types II and X collagen expressed in the condyles of adult rats was compared with that formed in response to forward mandibular positioning and the levels of expression were correlated to the amount of bone formed in response to mandibular advancement. Seventy-eight 120-day-old female Sprague-Dawley rats were included in this study. The rats were randomly allocated to six groups. Each group consisted of nine rats with bite-jumping devices and four untreated controls. The animals in each group were sacrificed on days 3, 7, 14, 21, 30, and 60. Immunostaining was used for the detection of types II and X collagen, while Alcian blue-PAS was used to observe the extracellular matrix and new bone formation. The results showed that new cartilage was formed in the posterior condyle. The highest level of expression of types II and X collagen were present on day 21, the amount of increase was 247.99 and 540.08 per cent, respectively. The highest level of new bone formation was measured at day 30 of advancement when the amount of increase in new bone formation was 318.91 per cent. These findings indicate that forward mandibular positioning causes changes in the biophysical environment of the temporomandibular joint (TMJ) of adult rats that leads to condylar adaptation.
本研究的目的是定量评估成年大鼠髁突对下颌前伸定位的适应性变化。将成年大鼠髁突中表达的II型和X型胶原蛋白水平与下颌前伸定位时形成的水平进行比较，并将表达水平与下颌前伸时形成的骨量相关联。本研究纳入了78只120日龄的雌性Sprague-Dawley大鼠。大鼠被随机分为六组。每组由9只佩戴咬跳装置的大鼠和4只未处理的对照大鼠组成。每组动物分别在第3、7、14、21、30和60天处死。采用免疫染色法检测II型和X型胶原蛋白，同时采用阿尔辛蓝-过碘酸雪夫染色法观察细胞外基质和新骨形成。结果显示，髁突后部形成了新的软骨。II型和X型胶原蛋白的最高表达水平出现在第21天，增加量分别为247.99%和540.08%。在向前移动30天时测量到新骨形成的最高水平，此时新骨形成的增加量为318.91%。这些发现表明，下颌前伸定位会导致成年大鼠颞下颌关节（TMJ）的生物物理环境发生变化，从而导致髁突适应。
