Kim M S, Jung S Y, Kang J H, Kim H J, Ko H M, Jung J Y, Koh J T, Kim W J, Kim S M, Lee E J, Kim S H
Dental Science Research Institute, 2nd stage Brain Korea, School of Dentistry, Chonnam National University, Gwangju, South Korea.
Anat Histol Embryol. 2009 Oct;38(5):321-6. doi: 10.1111/j.1439-0264.2009.00938.x. Epub 2009 Aug 13.
The development of the mandibular condylar cartilage is important for the overall growth of the mandible. However, there have been a few researches into medical approaches aimed at controlling condylar growth. This study examined the effects of bisphosphonate on the growth of the condylar cartilage. Alendronate (3.5 mg/kg/week) was administered to postnatal day 1 SD rats for 7 and 10 days. The thickness of each chondrocyte layer and the level of MMP-9 expression were measured. The anteroposterior diameter of the developing condyle was unaffected by the alendronate treatment for 7 days (P > 0.05). The total thickness of the cartilage layers was also unaffected by the treatment for 7 days (P > 0.05). In particular, there was no change in the thickness of the perichondrium and reserve cell layer at the measured condylar regions (P > 0.05). However, the thickness of the proliferating cell layer was reduced significantly, whereas the thickness of hypertrophied cartilage layer was increased (P < 0.05). The number of chondroclasts engaged in hypertrophied cartilage resorption was reduced significantly by the alendronate treatment (P < 0.05). The level of MMP-9 expression was reduced at both the transcription and translation levels by the alendronate treatment for 7 and 10 days. These results indicate that alendronate (>3.5 mg/kg/week) inhibits the longitudinal growth of the mandibular condyle by inhibiting chondrocyte proliferation and the resorption of hypertrophied cartilage for ossification.
下颌髁突软骨的发育对下颌骨的整体生长至关重要。然而，针对控制髁突生长的医学方法的研究却很少。本研究检测了双膦酸盐对髁突软骨生长的影响。将阿仑膦酸钠（3.5毫克/千克/周）给予出生后第1天的SD大鼠，持续7天和10天。测量各软骨细胞层的厚度以及MMP-9的表达水平。阿仑膦酸钠治疗7天对发育中髁突的前后径无影响（P>0.05）。治疗7天对软骨层的总厚度也无影响（P>0.05）。特别是，在测量的髁突区域，软骨膜和储备细胞层的厚度没有变化（P>0.05）。然而，增殖细胞层的厚度显著降低，而肥大软骨层的厚度增加（P<0.05）。阿仑膦酸钠治疗显著减少了参与肥大软骨吸收的破骨细胞数量（P<0.05）。阿仑膦酸钠治疗7天和10天在转录和翻译水平均降低了MMP-9的表达水平。这些结果表明，阿仑膦酸钠（>3.5毫克/千克/周）通过抑制软骨细胞增殖和肥大软骨的吸收以促进骨化，从而抑制下颌髁突的纵向生长。
