BAGATTO, B.*; WOLOSZYN, L.; BURGGREN, W.: 3-D Visual Assessment of Cardiovscular Function in Zebrafish Larvae

Numerous investigators are now measuring stroke volume of developing vertebrates by optical examination. The standard method for many animals, including zebrafish larvae, involves fixing the larvae, and capturing two dimensional video of lateral views of the beating heart through an inverted microscope. To arrive at a volume, the zebrafish heart is assumed to be in the shape a prolate spheroid. However, during early larval development, the zebrafish heart is shaped more like a tube, which begins to S-fold as it develops into its final shape. To assess stroke volume, and then, calculate cardiac output in these young larvae, a third dimensional measurement is needed. Our technique involves securing the living, intact larva, in a low temperature melting point agarose cylinder. The larva is then rotated through a full 180 degrees beginning at one lateral view, through the ventral view, to the other lateral view. The resulting three dimensional representation of the developing heart as it beats allows for more accurate calculation of diastolic and systolic volume, and hence stroke volume and cardiac output. In addition, this technique allows us to quantify the formation and three dimensional shape of vessels during early development. (supported by NSF IBN 98-96388).