Characterisation of transverse slice culture preparations of postnatal rat spinal cord: preservation of defined neuronal populations.

Spinal cord injury induces degenerative and regenerative processes and complex interactions of neurons with non-neuronal cells. In order to develop an in vitro tool for the investigation of such processes, we prepared and characterised spinal cord slice cultures (SCSC) from Wistar rats (p0-12). SCSC were sustained in vitro up to 12 days and characterised by immunohistochemistry. Calbindin+ neurons, distributed across the entire gray matter, were visible also after longer culture periods. NeuN+ neurons were best preserved in the dorsal horn whereas large NeuN+ and choline acetyltransferase+ motoneurons in the ventral horn vanished after 3 days in vitro. Nestin immunoreactivity was found in animals of all age groups, either in cells interspersed in the ependymal lining around the central canal or in cells resembling protoplasmic astrocytes. Glial fibrillary acidic protein+ astrocytes, initially restricted to the white matter, invaded the gray matter of SCSC early during the culture period. Microglial cells, stained by Griffonia simplicifolia isolectin B4, were rapidly activated in the dorsal tract and in the gray matter but declined in number with time. SCSC derived from p0 or p3 animals showed a better preservation of the cytoarchitecture than cultures derived from older animals. In summary, SCSC undergo degenerative changes, but they contain defined neuronal populations, the cytoarchitecture is partially preserved and the glial reaction is limited.