Characterization of the larynx in ephrin-B2 knockout mice: a novel animal model for laryngeal clefts.

Abstract

OBJECTIVE: To identify and classify laryngeal clefts in a novel mouse model. DESIGN: In vivo animal study. SETTING: Academic research laboratory. SUBJECTS: 129/CD1 mice with the ephrin-B2 gene disrupted by the β-galactosidase (lacZ) gene were humanely killed at embryonic day 18 (E18) and evaluated for the presence and characterization of a laryngeal cleft. Homozygous and heterozygous lacZ knockout mice as well as wild-type littermates were evaluated. MAIN OUTCOME MEASURES: Microsurgical dissection of the oral cavity and pharynx allowed for a pseudoendoscopic view of the larynx to determine the presence or absence of a cleft. The specimens were also histologically sectioned and examined for characterization and classification of the cleft. RESULTS: A laryngeal cleft was identified in 12 of 27 ephrin-B2 homozygous lacZ knockout mice (44%). Laryngeal clefts were not identified in heterozygous ephrin-B2 knockout mice or in wild-type littermates. CONCLUSIONS: Disruption of ephrin-B2 reverse signaling results in laryngeal clefts in lacZ knockout mice. This presents a novel mouse model in which future investigations into etiology of laryngeal clefts may be examined.