Establishment of experimental glioma models at the intrinsic brainstem region of the rats

Objectives: As the treatment of human intrinsic brainstem gliomas remains challenging, experimental glioma models are needed. Methods: We developed a rat model of intrinsic brain stem glioma that uses a stereotactic frame to fix the head for the delivery of C6 glioma cells to target sites via a permanently implanted cannula. We inoculated the rat midbrain, pons or cerebral cortex with 5 6x10(4) cells suspended in 1 ml culture medium over the course of 2 minutes. Results: Three days post-implantation, tumor formation was visible in the periaqueductal gray matter in the midbrain and the tegmentum of the pons. On the tenth day, the tumor diameter exceeded over 2 mm; there was no tumor cell seeding into the cerebrospinal fluid space. The tumor manifested the histological features typical of glioblastoma; Ki-67 labeling index was 32%. Discussion: Because in our model the cannula is permanently implanted, additional inocula can be delivered. Here we detail our rat brainstem glioma model and discuss its usefulness for the investigation of these tumor in humans.