Bioluminescence imaging analysis. (A) Ex vivo bioluminescence imaging analysis after rectal administration of vesicular stomatitis virus-G protein (VSV-G)-pseudotyped lentivirus (LV) expressing firefly-luciferase (fLuc). This pseudocolor image, which is superimposed on a grayscale reference image, uses color (blue, least intense; red, most intense) to illustrate signal strength. (B) Photon emission (p/s/cm2/sr) in the region of interest (ROI) of colon transduced by VSVG-pseudotyped LV shows significantly higher levels of transduction compared to the mock control. (C) Biodistribution of VSV-G LV after rectal administration demonstrated by real-time quantitative polymerase chain reaction (qPCR) analysis of viral copy number in 300 ng of genomic DNA of in vivo (equivalent to approximately 50,000 cells). The detection limit was 50 copies per 300 ng genomic DNA.