Rabie A Bakr M, Tsai Ming-Ju Marjorie, Hägg Urban, Du Xi, Chou Bing-Wu
Faculty of Dentistry, The University of Hong Kong, Prince Philip Dental Hospital, Hong Kong SAR, People's Republic of China.
Angle Orthod. 2003 Aug;73(4):457-65. doi: 10.1043/0003-3219(2003)073<0457:TCORCA>2.0.CO;2.
The aim of this study was to quantify the number of replicating mesenchymal cells and to correlate it to the amount of bone formation in the condyle during stepwise advancement of the mandible. Two hundred and fifty female Spraque-Dawley rats, 35 days old, were randomly divided into 10 control groups (n = 5) and 20 experimental groups (n = 10). Fifty rats from the stepwise experimental group relieved a two-mm advancement initially and veneers were added on day 30 with another 1.5 mm advancement. The rats were sacrificed after 3, 7, 14, 21, 30, 33, 37, 44, 51, and 60 days. One hour before death, all rats were injected with bromodeoxyuridine (BrdU) intravenously. Tissue sections of seven microm were cut through the condyle in the sagittal plane and stained with anti-BrdU antibody to evaluate the number of replicating mesenchymal cells. Haematoxylin stain was applied to observe cellular response. The results indicated that during the first advancement, replicating mesenchymal cells in the posterior region of the condyle showed the highest increase on days 7 and 14 when compared with the control. Such an increase preceded the highest level of bone formation between days 30 and 37 of advancement. In response to the second advancement, another increase of replicating cells was evident on day 44, along with a significant increase in bone formation observed on day 60. We concluded that forward positioning of mandible in a stepwise manner delivers a mechanical strain that solicits an increase in the number of replicating mesenchymal cells in the condyle. The increase in the population size of the osteoprogenitor cells subsequently leads to more bone formation.
本研究的目的是量化增殖间充质细胞的数量，并将其与下颌骨逐步前移过程中髁突的骨形成量相关联。250只35日龄的雌性Sprague-Dawley大鼠被随机分为10个对照组（n = 5）和20个实验组（n = 10）。逐步实验组的50只大鼠最初前移2毫米，在第30天添加贴面并再前移1.5毫米。在第3、7、14、21、30、33、37、44、51和60天后处死大鼠。在死亡前1小时，所有大鼠静脉注射溴脱氧尿苷（BrdU）。在矢状面切取7微米厚的髁突组织切片，用抗BrdU抗体染色以评估增殖间充质细胞的数量。应用苏木精染色观察细胞反应。结果表明，在第一次前移过程中，与对照组相比，髁突后部增殖间充质细胞在第7天和第14天增加最多。这种增加先于前移第30天至37天期间骨形成的最高水平。在第二次前移后，第44天增殖细胞再次明显增加，同时在第60天观察到骨形成显著增加。我们得出结论，下颌骨逐步向前定位会产生机械应变，促使髁突中增殖间充质细胞数量增加。骨祖细胞数量的增加随后导致更多的骨形成。
