Inoculation of C6 glioma cell suspension into the brain of adult rats: morphological study.

The C6 astrocytoma cell line was inoculated intracerebrally as suspension into the rat brain. Tumors were allowed to grow 2 to 60 days and their development was studied on coronal sections at these survival times. Tumor cells developed intraparenchymal solid tumor at the implantation site. C6 cells also filled out the needle track-area and spread into meninges. At 2 days postimplantation (2 DPI), tumor cells were observed to infiltrate recipient's brain directly from the implantation site or via perivascular spaces of adjacent cerebral blood vessels. Some cells escaped from the implantation channel during transplantation. They spread diffusely via cerebrospinal fluid (CSF) in leptomeningeal regions over the brain surface. At 10 DPI, the tumor mass invaded the adjacent brain parenchyma as well as cerebral ventricles (CV) and C6 cells could spread intraventricularly. At 30 DPI, tumor extremely increased its size and its growth was expansive. It exhibited areas of necrosis and later on, at 60 DPI, inoculated rat brains revealed large empty pseudocysts resulting from decay of necrotic tumor masses.