Abstract: Objective To optimize the luciferase bioluminescence reporting system and to investigate its application in xenografted human HepG2 cell transplantation in nude mice.Methods A certain number of HepG2-Luc cells with stable expression of luciferase（fixed luciferase amount） were conducted for optimization of luciferin and ATP concentration. The sensitivity and luminescence intensity of the optimized substrate and ATP concentration were analyzed in vivo for the tumor cell imaging in nude mice.Results The optimal concentration of luciferin was 1.25 mg/ml and the optimal concentration of ATP buffer was 12.5 μM in in vivo imaging experiments;the intensity of subcutaneous injection of 2×10⁶ HepG2-Luc cells was 484645,while it became 1483024 when the optimized system was used;the ratio of signal intensity between experimental and control mice was 0.11,while it became 0.67 after the optimized system was used,suggesting that in vivo imaging with this optimized luciferase reporting system could significantly improve the sensitivity of tumor detection and prolong the luminescence time in nude mice. Conclusion An optimized luciferase bioluminescence reporting system is established,which might be used in in vivo study for tumor detections.

Key words: HepG2 cells, In vivo imaging, Bioluminescence, Luciferase, Nude mice