Three-dimensional analysis of laryngeal cartilage development

The process of laryngeal cartilage growth during the recanalization of the glottis has not been resolved. Therefore, we performed 3-dimensional analysis of the process of laryngeal cartilage development in utero . This study examined fetal mice at embryonic day (E)13.5–E17.5. The 3-dimensional structure of the laryngeal cartilage was reconstructed from serial slices of the entire larynx, and its morphology was observed and measured. Immunohistochemical staining was also performed with anti-SOX9 and anti-ColII antibodies to investigate the differentiation process of chondrocytes. At E13.5 the laryngeal cartilage was a single mass, but at E14.5 it had divided to form the thyroid cartilage (TC), cricoid cartilage (CC), and arytenoid cartilage (AC). Recanalization of the glottis occurred from E15.5 to E16.5, and the upper part of the laryngeal cartilage supporting the glottis also underwent substantial growth during this period. At E17.5, following recanalization of the glottis, growth of the laryngeal cartilage supporting the infraglottic region occurred. The laryngeal cartilage supporting the glottis underwent rapid growth during recanalization. This finding suggested that laryngeal cartilage growth may support the recanalization of the glottis.