Objective: To detect the different morphologic features, developmental regulation, potential of proliferation and differentiation of neonatal rat cochlea progenitor spheres. Methods: We isolated the cochlea sensory epithelium cells from neonatal rats and cultured them in nonadherent conditions to acquire different morphologic spheres. Then we observed the diameter and compositional change of cell colonies in distinct sphere types on day 3, 6, 9 and 12, and summarized the regularity of development and their conversion. We also detected the proliferative activity of distinct spheres by immunohistochemical staining of Abcg2, Nestin and BrdU. After induced spontaneous differentiation, the spheres were detected in the changes of the marker of hair cell, MyosinVIIA; by immunocytochemical staining, we revealed the potential of how different spheres were converted into hair cell-like cells. Results: The acquired three types of suspended spheres are solid, transitional, and hollow. There's morphologic significance among them and they can covert into the other type of spheres among them. The ability of self-renewing and proliferation in distinct spheres vary and all of them have the potential of spontaneously differentiation into hair cell-like cells. Conclusion: All the type of spheres not only has the potential of proliferation and differentiation, but also hasthe potential of spontaneous differentiation into hair cell-like cells. Distinct types of cell spheres neither originate from different progenitor cell subcolonies nor are different stages of the same cell spheres. Solid spheres are most practically useful.
