Neural Cell Apoptosis in Postnatal Developing Spiral Ganglion of Rat / 听力学及言语疾病杂志

ABSTRACT

Objective To study cell apoptosis and differentiation in postnatal developing spiral ganglion(SG)of rat.Methods By means of transmission electron microscope(TEM),cell apoptosis and the ultrastructure of rat SG neurons were investigated during postnatal days 1,3,5,7,10,14,and 30.Results In P5 and P7,neural cell apoptosis was observed in rat SG neuron.The typical morphological alterations of apoptotic cells included a crescent-shaped band of condensed chromation round the nuclear periphery,apoptotic bodies,and cell shrinkage.The first appeared type 2 neurons with densely packed neurofilaments in the cytoplasm could be recognized with confidence at postnatal day 7.The type 2 neurons at this time showed obvious signs of cell shrinkage.Cell apoptosis disappeared subsequently.In subsequent developing period,the morphological characteristics of type 1 and type 2 neurons became more remarkable and gradually achieved their mature structure.Conclusion The neural cell apoptosis was an important event in the postnatal development of rat SGCS.Cell apoptosis,occurred prior to appearance of the type 2 neurons,may be related to remodeling of the outer hair cell innervation and type 2 neuron differentiation.