Cardiac function and blood flow hemodynamics assessment of zebrafish (Danio rerio) using high-speed video microscopy

Background: In the last few decades, zebrafish (Danio rerio) were introduced as a model organism to investigate human diseases including cardiovascular and neuronal disorders. In most zebrafish investigations, cardiac function and blood flow hemodynamics need to be assessed to study the effects of the interference on the cardiovascular system. For heart function assessment, most important parameters include heart rate, cardiac output, ejection fraction, fractional area change, and fractional shortening. Methods: A 10 s high-speed video of beating heart and flowing blood within major vessels of zebrafish that are less than 5 days post fertilization (dpf) were recorded via a stereo microscope equipped with a high speed camera. The videos were analyzed using MicroZebraLab and image J software for the assessment of cardiac function. Results: Using the technique described here, we were able to simply yet effectively assess cardiac function and blood flow dynamics of normal zebrafish embryos. We believe that the practical method presented here will help cardiac researchers using the zebrafish as a model to examine cardiac function by using tools that could be available in their laboratory.