Craniofacial Development and Tissue Biology, Tohoku University Graduate School of Dentistry.
Biomed Res. 2023;44(2):65-72. doi: 10.2220/biomedres.44.65.
Mice devoid of matrix metalloproteinase (MMP)-2 due to gene targeting have been reported to show articular cartilage destruction in the knee joint; however, the phenotype of the mandibular condylar cartilage remains unknown. Thus, in the present study, we investigated the mandibular condyle in Mmp2 mice. We obtained and bred Mmp2 mice from the same source as the previous study, and performed genotyping using genomic DNA extracted from finger snips. The mandibular condyle of Mmp2 mice and wild-type (WT) mice was immunohistochemically examined for the localization of extracellular matrix (ECM) proteins (type I and II collagen, and aggrecan), and MMP-9 and MMP-13. No cartilage destruction was observed in the mandibular condyle of Mmp2 mice, and no difference was found in the localization of the ECM proteins between the Mmp2 mice and WT mice. However, the bone marrow cavity in the subchondral bone of the mandibular condyle was more distinct in Mmp2 mice than in WT mice at the age of 50 weeks. Of note, MMP-9 characteristically localized in multinucleated cells in the mandibular condyle in 50-week-old Mmp2 mice. MMP-2 may be involved in the regulation of osteoclast differentiation and the formation of the bone marrow cavity in aged mice.
由于基因靶向而缺乏基质金属蛋白酶（MMP）-2 的小鼠已被报道在膝关节中显示关节软骨破坏；然而，下颌髁状突软骨的表型尚不清楚。因此，在本研究中，我们研究了 Mmp2 小鼠的下颌髁。我们从与之前研究相同的来源获得并繁殖了 Mmp2 小鼠，并使用从小指剪下的基因组 DNA 进行基因分型。使用免疫组织化学检查 Mmp2 小鼠和野生型（WT）小鼠下颌髁的细胞外基质（ECM）蛋白（I 型和 II 型胶原和聚集蛋白聚糖）、MMP-9 和 MMP-13 的定位。在 Mmp2 小鼠的下颌髁中未观察到软骨破坏，并且在 Mmp2 小鼠和 WT 小鼠之间 ECM 蛋白的定位没有差异。然而，在 50 周龄时，Mmp2 小鼠下颌髁的软骨下骨中的骨髓腔比 WT 小鼠更明显。值得注意的是，MMP-9 特征性地定位于 50 周龄 Mmp2 小鼠的下颌髁多核细胞中。MMP-2 可能参与调节破骨细胞分化和老年小鼠骨髓腔的形成。
