네오마이신 이독성이 유도된 마우스 달팽이관에서 Wnt가 sphere 형성 및 고실 경계 세포의 증식에 미치는 영향

Wnt signal increases the sphere-forming activity and the cell proliferation in tympanic border cell area in the postnatal mouse cochlea after neomycin-induced ototoxicity

Although Wnt genes are expressed in mammalian cochlear tissues and are involved in the development of the inner ear, their exact roles on proliferation in the postnatal cochlea are unknown. We hypothesize that exogenous Wnt agonists may promote the self-renewal in the neomycin-damaged postnatal mouse cochlea. Cochlea of P3 wildtype(CD1) mice were harvested and cultured in vitro. 0.5mM neomycin was used to induce hair cell loss. Wnt agonists used in this experiment were as follows; tcf/lef agonist, R-spondin-1, LiCl, wnt3a and R-spondin-1-Fc. The ability to form floating clonal colonies was evaluated by sphere assay and proliferating capacity was evaluated by immunohistostaining for Ki as well as by EdU assay. Immunolabeled cells were quantified following 3D reconstruction of z-stack images using Velocity 􄠶 software(Velocity Software Inc.). This experiment demonstrated that exogenous Wnt agonists increase self renewal of dissociated cochlear cells. It also showed that Wnt agonists increase the proliferation of tympanic border cells in a cochlea in vitro. In this experiment, neomycin-induced damage increased proliferation in cochlea, and treatment with Wnt agonists further increased this proliferation.