Bioluminescent Tumor Signal Is Mouse Strain and Pelt Color Dependent: Experience in a Disseminated Lymphoma Model.

Background: Many preclinical cancer studies use mice with varied phenotypes to monitor tumor treatment. We compared survival and optical imaging characteristics of strains with varied coat colors harboring luciferase-expressing disseminated lymphoma.
Results: Luciferase-expressing lymphoma cells (Raji-luc) were injected via tail vein into severe combined immunodeficient (SCID) and Rag2-IL2rg (R2G2) mice, and survival was tracked. Tumor signals were obtained by imaging ventral and dorsal aspects of mice. Signal attenuation by isolated mouse pelts was measured in vitro. R2G2 mice had decreased survival compared to SCID mice (17 vs. 32 days, p<0.001) despite similar bioluminescence signal when mice were imaged dorsally (p=0.37). However, signal was 17.3-fold higher in R2G2 mice compared to SCID (p<0.001) when imaged ventrally. Isolated dark R2G2 dorsal pelts attenuated signal more than ventral pelts when placed over cells in vitro.
Conclusions: Mouse pelt color and imaging aspect are critical considerations for quantifying bioluminescent tumor signal, and the R2G2 mouse strain may prove useful for preclinical targeted therapy studies.
(© 2021. World Molecular Imaging Society.)