ABSTRACT
Objective To investigate the neural proliferation , differentiation and apoptosis of the developing spinal cord of the mouse and to discuss the mechanism of spinal cord ’ s development .Methods 5-Bromodeoxyuridine ( BrdU) assay was used to mark the proliferative neural stem cells , and the immunofluorescent stainings ( DCX, NeuN and Caspase8) were carried out to visualize the newborn neurons , mature cells and apoptotic cells in the spinal cord with 173 mice arrange from E18 to P90.Results BrdU positive neural stem cells appeared evenly in the spinal cord at early days . With age increasing , the neural stem cells differentiated into neuroglial cells and neurons .The newborn neurons in the subventricular zone migrated toward the intermediate zone ( putative gray matter ) and differentiated into mature neurons gradually .With neurons ’ concentrating towards the center , the gray matter formed an “H” shape .In the meantime , with neural differentiation , some apoptotic neurons appeared among the newborn neurons and mature neurons . Double immunostaining showed that most apoptotic neurons were newborn neurons , suggesting the neuroapoptosis more likely occurred in newborn neurons .The statistical data showed that the number of DCX , NeuN and Caspase-8 positive cells reduced with age increasing , suggesting neural differentiation and neuroapoptosis decreased during spinal cord ’ s development .Conclusion Neural proliferation , neural differentiation and neuroapoptosis occur in developing spinal cord . They work together to regulate the formation and development of the spinal cord .
