Fine structure of PC12 cell implants in the rat spinal cord

PC12 cells, a clonal cell line established from a rat pheochromocytoma, were injected into the subarachnoid space in the lumbar spinal cord of adult rats. These cells invaded the spinal cord as a metastatic tumor and, after 2 weeks, displaced one-third of the cord parenchyma, causing hind limb paralysis. The tumor consisted of densely packed cube-like polygonal cells containing dense core granules. At the tumor-host margins there were no astrocytic or other intervening glial processes. In spite of the destruction and invasion of the spinal cord tissue parenchyma that occurred, no glial reaction could be seen. The endothelial cells of the capillaries in the vascularized tumor are of the attenuated, fenestrated type in contrast to the non-fenestrated type of the host tissue from which they were derived.