Ten congenitally athymic "nude" mice and 10 immunocompetent mice underwent intrathecal inoculation with a human
glioblastoma cell line (U87MG) via percutaneous lumbar puncture (5 x 10(5) cells/animal). All of the nude mice developed
paraplegia with or without incontinence at 2 weeks and routinely died of inanition 3 weeks postimplantation. Histological examination confirmed extensive proliferation of neoplastic cells within the intrathecal space. A second group of animals was inoculated with 5 x 10(4) cells/animal: 20 nude mice, 10
cyclosporine A-immunosuppressed animals, and 10 immunocompetent control mice. The 20 mice were further divided into four subsets. Subset A did not receive
chemotherapy, Subset B received 200 mg of
carmustine (
BCNU) per m2 by
intraperitoneal injection, Subset C received a single dose of 4 mg of
methotrexate (MTX) per m2 by
intrathecal injection 4 hours after
tumor inoculation, and Subset D received 12 mg of intrathecal MTX per m2. Decreasing the concentration of cells per animal by 1 log doubled the time interval required for the development of
paralysis and incontinence to 4 weeks. Treatment with intrathecal MTX at a dose of 4 mg/m2 extended the symptom-free period by an additional week (to 5 weeks postinoculation), and a dose of 12 mg/m2 allowed an average of 6 weeks before the onset of neurological impairment. The xenografts did not grow in the immunocompetent control mice, the
BCNU-treated group, or the
cyclosporine A-immunosuppressed animals. An intrathecal xenograft model of central nervous system
malignancies allows a novel approach to the evaluation of experimental
chemotherapy.(ABSTRACT TRUNCATED AT 250 WORDS)