The Common Marmoset as a Novel Non-human Primate Model for Inner Ear Research

Abstract

Recent advances in molecular biology have led to significant progress in the fields of otology and audiology. Rodents, particularly genetically modified mice, have traditionally served as the primary model for inner ear research. However, growing evidence highlights inter-species differences in hearing research. Simultaneously, the use of human inner ear specimens has become increasingly restricted due to difficulties in specimen collection and ethical concerns. Similarly, the use of human fetuses to study inner ear development is challenging due to ethical issues. Therefore, the embryology of the mammalian inner ear cochlea has been studied using rodent models. These challenges underscore the need for a new research platform that better approximates the human inner ear. The common marmoset (Callithrix jacchus), a New World monkey native to South America, has emerged as a promising alternative. Initially studied in adult models, this primate is now being applied to developmental inner ear research. Its use is expected to yield novel insights. Offering a viewpoint distinct from conventional rodent-based studies. In this study, we outline the advantages of the common marmoset in hearing research and discuss its potential as a primate model animal for future inner ear studies.

Keywords: cochlea; common marmoset; hearing loss; primate model.

Figure 1.

Primate phylogenetic tree. The common marmoset of New World monkeys is more closely related to humans than to rodents, followed by Old World monkeys.

Figure 2.

Histology of the newborn cochlea of the common marmoset. The newborn cochlea of the common marmoset has 2 and a half turns, the same as the adult cochlear (A). Immunohistochemical analysis can be applied to this primate cochlea. One row of inner hair cells and 3 rows of outer hair cells can be clearly observed (B and C). IHC: inner hair cells, MYO7A: hair cell markers; OHC: outer hair cells; SOX2: supporting cell markers.

Figure 3.

Developmental, morphological changes of the cochlea of the common marmoset. During the cochlear development, the cochlear duct changes its morphology. Previous studies on developmental investigation in primate cochlea have described their general time course. The common marmoset has become a novel developmental study model animal in this field. OC: organ of Corti, StV: stria vascularis.

Figure 4.

Usefulness of the common marmoset in hearing research. The common marmoset is a promising new animal model in the fields of otology and audiology. Common marmosets may be useful in studies of hearing loss and aging, as well as in studies of genetic hearing loss and developmental biology.