Figure 2: Immunohistochemistry of Sox9 and Runx2 in mandibular cartilages of mice at newborn stage. Sox9 (a, b, and e) and Runx2 (c, d, and g) showed similar expression patterns throughout all the mandibular cartilages. In condylar cartilage (a and c), angular cartilage (b and d), and symphyseal secondary cartilage and rostral cartilage (e and g), both Sox9 and Runx2 were strongly expressed by cells entire hypertrophic cell zone. Scale bar: 100 μm for (a, b, c, and d) and 50 μm for (e and g). Results of Sox9 (f) and Runx2 (h) immunohistochemistry in hypertrophic zones of mandibular cartilages including condylar (CD), angular (AG), and symphyseal secondary cartilage (SS), and rostral process (RC), posterior Meckel’s (PM), and extramandibular Meckel’s (EM) cartilage were quantitated by average optical density of positive staining per 200 field (**). The expression levels of both transcriptional factors in the posterior portion of uncalcified intramandibular Meckel’s cartilage (b and d) were significantly reduced than in other cartilages.