OBJECTIVETo establish red-green dual-color fluorescence glioma model in nude mice and to explore its practical values.

METHODSCM-DiI-stained rat glioma C6 cells (C6-CM- DiI cells) expressing red fluorescence were inoculated into the brain of athymic nude mice expressing green fluorescence protein (NC-C57BL/6J-EGFP). Then the whole-body dual-color fluorescence imaging was detected dynamically. Finally whole brains of the tumor-bearing mice were removed and 5 µm thick serial frozen slices were made. Light microscopy, fluorescence microscopy and confocal laser scanning microscopy were performed to observe the transplanted tumor tissue structure and fluorescent cells.

RESULTSTumor mass with red fluorescence increased gradually under continuous in-vivo fluorescence imaging monitoring. Under the fluorescence microscope, cells with red, green and yellow fluorescence were observed in the frozen sections of transplanted tumor tissue and the mutual structural relationship among them could be defined. The tumor cells migration, implantation and cell fusion between transplanted tumor cells and host cells could be observed. It could be distinguished according to the fluorescence, that blood vessels of tumor-origin displayed red fluorescence, blood vessels of host-origin displayed green fluorescence and mosaic blood vessels appeared yellow fluorescence. It was depicted that host innate astrocytes and oligodendrocytes in the microenvironment at the tumor periphery could be activated and dedifferentiated into nestin-positive cells.

CONCLUSIONSIn contrast to traditional animal model, the dual-color fluorescence imaging of nude mouse models of glioma possesses enormous advantages in investigating tumor mass in-vivo fluorescence imaging, tumor cells migration and metastasis, tumor angiogenesis and reactive activation of host innate cells in the microenvironment at tumor periphery, thus, has highly practical application value.