An automated sensitive approach for measuring whole gut transit time

Background

Commonly used methods to measure whole gut transit time in rodents have yet to combine high sensitivity, objectivity and automation. We have developed a novel method using oral gavage of non-toxic fluorescent dye particles and their detection by fluorescence imaging to enable unbiased automated detection of gut transit time simultaneously in 8 cages.

Methods

Naïve mice (n=20) were gavaged with a 4.4% suspension of fluorescent dye in CMC in 3 groups on 2 occasions. Each group was imaged in 8 cages at 5-minute intervals using blue LEDs for illumination and a Sony full-frame mirrorless camera with a green band-pass emission filter. Custom Matlab code counted the number of fluorescent boli per cage post-hoc and provided graphical and spreadsheet output. Boli counts across a wide range of parameters were compared to blind assessments by an experimenter.

Results

Fluorescent boli were detected with high sensitivity, while unstained boli were readily rejected. All cage...