High-throughput Measurement of Gut Transit Time Using Larval Zebrafish

Area of Science:

• Pharmacology
• Toxicology
• Zebrafish Models

Background:

• Gastrointestinal (GI) intolerance is a common issue in drug development, posing risks to human health.
• Preclinical mammalian models for GI toxicity testing are costly and time-consuming.
• Zebrafish share significant physiological similarities with mammals, making them a viable alternative model.

Purpose of the Study:

• To develop and validate a high-throughput method for assessing drug-induced GI toxicity using zebrafish.
• To enable rapid, cost-effective screening of drug candidates for GI safety.
• To support the principles of the 3Rs (Replacement, Reduction, Refinement) in animal testing.

Main Methods:

• Larval zebrafish (7 days post fertilization) were fed fluorescently labeled food.
• Fish were subsequently dosed with test compounds or vehicle in a 96-well plate format.
• Gut transit time was monitored by measuring fluorescence of fecal matter accumulation over time using a plate spectrophotometer.

Main Results:

• The method accurately detected changes in GI transit time induced by drugs with known clinical GI effects.
• The assay demonstrated high throughput, capable of evaluating dozens of treatments daily.
• The approach requires minimal test compound quantities compared to mammalian models.

Conclusions:

• This zebrafish-based assay is an effective tool for predicting potential GI safety issues of drug candidates.
• The high-throughput nature expedites the drug discovery process by enabling early prioritization of safer compounds.
• This method offers a valuable alternative to traditional mammalian models, aligning with ethical considerations in preclinical research.