Comparison of noninvasive fluorescent and bioluminescent small animal optical imaging.
Optical imaging is a modality that is cost-effective, rapid, easy to use, and can be readily applied to studying disease processes and biology in vivo. For this study, we used a green fluorescent protein (GFP)- and luciferase-expressing mouse tumor model to compare and contrast the quantitative and qualitative capabilities of a fluorescent reporter gene (GFP) and a bioluminescent reporter gene (luciferase). We describe the relationship between tumor volume, tumor mass, and bioluminescent/fluorescent intensity for both GFP and luciferase. Bioluminescent luciferase imaging was shown to be more sensitive than fluorescent GFP imaging. Luciferase-expressing tumors were detected as early as 1 day after tumor cell inoculation, whereas GFP-expressing tumors were not detected until 7 days later. Both bioluminescent and fluorescent intensity correlated significantly and linearly with tumor volume and tumor weight, as measured by caliper. Compared to bioluminescent imaging, fluorescent imaging does not require the injection of a substrate and may be appropriate for applications where sensitivity is not as critical. Knowing the relative strengths of each imaging modality will be important in guiding the decision to use fluorescence or bioluminescence.
Choy
Garry
G
National Cancer Institute, NIH, Bethesda, USA.
O'Connor
Sarah
S
Diehn
Felix E
FE
Costouros
Nick
N
Alexander
H Richard
HR
Choyke
Peter
P
Libutti
Steven K
SK
D000818:Animals; D014408:Biomarkers, Tumor / Q000378:metabolism*; D045744:Cell Line, Tumor; D005260:Female; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008156:Luciferases / Q000378:metabolism*; D008164:Luminescent Proteins / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008856:Microscopy, Fluorescence / Q000379:methods*; D009369:Neoplasms / Q000175:diagnosis* / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D014408:Biomarkers, Tumor; D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D008156:Luciferases