Intramedullary canine spinal cord tumor model.

The development of a transplantable model brain tumor in the neonatal dog, the adaptation of the tumor to tissue culture, and the successful growth of the tumor in adult mongrel dogs has been adapted to producing similar tumors in the thoracic spinal cord of the adult dog. Ten adult dogs, weighing 4 to 25.4 kg each, were subjected to formal laminectomy. The tumor cell suspension was injected by hand with a Hamilton syringe at two or three sites over a distance of 1 cm; each site received an injection volume to 0.02 to 0.05 cc of the cell suspension after the dura had been opened. Immediately after injection the field was copiously irrigated and the puncture area sealed with a single drop of ethyl cyanoacrylate. Tumor cells for injection were obtained by thawing ampules stored at -195 degrees C in a mixture of 10% dimethyl sulfoxide and RPMI 1640 culture medium. Cells were resuspended in Hank's balanced salt solution and 15% fetal calf serum on ice. Solutions had 90% cell viability, and animals received a dose in the range of 3 to 13 X 10(6) cells. Eight animals developed tumors and became paraparetic on the 9th to 14th postinjection day. Metrizamide myelography in three animals revealed complete blocks; two animals underwent spinal computerized tomography (CT) and demonstrated syringohydromyelia. Histology revealed the tumors to be highly vascular primitive neoplasms that invaded the surrounding cord. This spinal cord tumor model is large enough to be operated on, studied by CT and myelography, and subjected to pharmacological, electrophysiological, and blood flow study.