Figure 3: Immunohistochemistry of Osterix in mandibular cartilages of mice at newborn stage. Osterix was at a extremely low level in condylar cartilage (in the red box of (a)) and angular cartilage (in the blue box of (b)) while intensely expressed in the center of the Meckel’s cartilage containing the strong basophilic matrix (in the yellow box of (b) and Figure 1(c)). Further, Osterix was moderately expressed in the rostral process (c). Scale bar: 25 μm for (a′, b′, and b′′) and 50 μm for (c). Results of Osterix (d) immunohistochemistry in 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 (*, **). Immunohistochemistry of Osterix in the posterior portion of intramandibular Meckel’s cartilage was significantly stronger and had more positive cells than in other cartilages.