Combined Optical and Acoustic Microscopy for Noninvasive Cardiovascular Studies Using Zebrafish Model

Zebrafish is a valuable animal model for cardiovascular research and development of innovative heart failure treatments. Zebrafish possess two-chamber heart, and their blood vessels bear a significant resemblance, both in structure and function, to those found in humans. Therefore, the measurement of cardiovascular parameters, such as heart rate, spatiotemporal distribution of blood flow velocity, and organ sizes, is of great importance. During the initial 5–7 days post-hatching, zebrafish embryos exhibit an optical transparency that enables a direct observation of cardiovascular system (CVS) development, including the intricate formations of the heart and blood vessels. However, as zebrafish continues growing up and becomes mature, their tissues gradually become less translucent, making it increasingly challenging to observe internal structures without causing harm to the organisms. During the larval and juvenile stages, researchers often turn to noninvasive acoustic methods to facilitate the visualization and measurement of the heart’s structure and function in live zebrafish. Consequently, the continuous measuring of the cardiovascular parameters—from the early heart development to full maturation—requires a combination of optical and acoustic modalities. In this study, we introduce a microscope-based instrument equipped with an integrated optical imaging system and an acoustic microscopy module. The optical system allows precise photoplethysmography measurement of cardiac performance and videocapillaroscopic mapping of blood vessels. This combined optical and acoustic microscopy instrument holds the potential to study zebrafish CVS development, and its responses to environmental influences, injuries, and diseases.