Abstract: Objective To establish C6 glioma model in rat brain and to study its biological behavior(such as the incidence of tumor development, the process of cell invasion pathological characteristics of C6 and neoangiogenesis, the spontaneous regression of experimental gliomas and the best experimental time window).Methods C6 tumor cells and DMEM were implanted into the right caudate of 50 male Wistar rats. 9 rats implanted DMEM is the control group. The animals were examined by MRI and pathological staining at postoperative day (POD) 3, 7, 14, 21,28, 35, and 50. Matrix metalloproteinases-2 (MMP-2) and CD₃₁ immunohistochemistry staining were used to study the histopathological features of the developed tumor. Methodology, physical findings and biological behavior were also discussed. Results 45 Wistar rats survived after surgery and tolerated MRI procedures well. On POD 7, there was a focal signal at the implantation site. The C6 cells sprout to the surroundings along the nerve fiber. During the day 14～28, the tumor exhibited a marked increase in size with focal mass effect, and immunohistochemical-staining shows MMP-2 and CD₃₁ is overexpression; C6 cells were aggregated and blood brain barrier were destroyed greatly. Most of the tumor bearing rats died within 30 days. But, C6 cells in the two rats retrogress spontaneously after more leucocytes rounded 28 days. HE staining shows tumors.Conclusion The characteristics of rat C6 brain tumor model mimicked the human tumor with respect to its development, progression, and invasion. Although, part of C6 tumor spontaneously regressed, it is a useful animal model of glioblastoma for pre-clinical evaluation of various therapeutic strategies for the management of glioblastoma. The best experimental time window is 14 to 28 days.

Key words: C6 cells, law of natural growth