Yerukhimovich Michael V, Bai Lianhua, Chen Daniel H-C, Miller Robert H, Alagramam Kumar N
Department of Otolaryngology, Head and Neck Surgery, Case Western Reserve University, Cleveland, Ohio 44106, USA.
Dev Neurosci. 2007;29(3):251-60. doi: 10.1159/000096415. Epub 2006 Oct 17.
Genetic, noise- and drug-induced loss of hair cells in the mouse and human cochlea leads to permanent hearing loss due to lack of regeneration of hair cells, which may be due to reduced numbers or loss of the regenerative ability of stem cells in the adult cochlea. We hypothesized that the mouse neonate cochlea harbors stem cells capable of differentiating into hair cells. Cells from the primary neonate cochlear culture began to proliferate and formed floating spheres after 14 days in vitro (DIV). By comparison, spheres from the primary culture of the cortex were observed after 7 DIV. Cochlear sphere cells could be passaged and the new spheres were observed after 7 DIV. Cochlear sphere cells were capable of differentiating into astrocytes and oligodendrocytes, but not neurons under the conditions tested. Cochlear sphere cells expressed Sox2 and Myo7a, but failed to show markers that are expressed exclusively in mature cochlear tissue, while cells from cortex spheres expressed Sox2 and Otx2, but not Myo7a. Our results show that cochleae from neonatal mice harbor cells capable of forming spheres and cells from these spheres appear to be better endowed to become hair cells.
在小鼠和人类耳蜗中，基因、噪音和药物导致的毛细胞损失会因毛细胞无法再生而导致永久性听力丧失，这可能是由于成年耳蜗中干细胞数量减少或再生能力丧失所致。我们推测新生小鼠耳蜗中存在能够分化为毛细胞的干细胞。来自原代新生耳蜗培养物的细胞在体外培养14天（DIV）后开始增殖并形成悬浮球。相比之下，皮质原代培养物的球在7 DIV后被观察到。耳蜗球细胞可以传代，并且在7 DIV后观察到新的球。在测试条件下，耳蜗球细胞能够分化为星形胶质细胞和少突胶质细胞，但不能分化为神经元。耳蜗球细胞表达Sox2和Myo7a，但未能显示在成熟耳蜗组织中特异性表达的标记物，而来自皮质球的细胞表达Sox2和Otx2，但不表达Myo7a。我们的结果表明，新生小鼠的耳蜗含有能够形成球的细胞，并且来自这些球的细胞似乎更有能力成为毛细胞。
