Bioluminescence imaging of in vivo model of brain metastasis, drugs administration and tumor irradiation

Tumor bioluminescence were viable for detection by the IVIS imaging system after 6 days’ incubation of LLC cells in orthotopic brain transplantation model and 14 days’ incubation of LLC cells in intracarotid injection model using an IVIS Spectrum scanner (Bruker, USA). A D-luciferin potassium salt solution (Goldbio. St. Louis, MO, USA) was injected intraperitoneally (150 mg/kg), and imaging of the mice continued until peak radiance could be acquired. Living Image Software (Bruker MI, USA) was used to measure the total flux of a brain tumor in automatically selected regions of interest.

The transplanted mice were divided into 4 groups (n=6 mice for each group) using random number table and random number remainder grouping: the normal saline (NS), ES, RT, and ES plus radiotherapy (ES + RT) groups. NS (0.1 mL) was given to mice in the NS and RT groups, while ES (15 mg/kg) was administered to mice in the ES and ES + RT groups for 14 days by intraperitoneal injection. And the day was set as day 1 when mice was grouped and treated. Mice in the RT and ES + RT groups were subjected to 10 Gy irradiation on day 7 after tumor bioluminescence imaging. Irradiation was administered with a Varian Clinac 600C X-ray unit at 250 cGy/min (80 cm source-to-skin distance). Prior to irradiation, anesthesia of 1% pentobarbital sodium was applied to all mice, and irradiation proceeded with a protective lead cover, and only the whole brain being exposed to the field. Mice brains were removed after tumor bioluminescence were detected on day 14. Fresh brain (six mice each group) were detected by flow cytometry or stored in −80 °C for western blotting. Some brains (six mice each group) were subsequently sectioned into pieces of 5 mm sections for histopathologically detection