The effect of retinoic acid on the cardiac ventricle-atria diversification in zebrafish

Purpose To study the effects of external retinoic acid (RA) on the development of the embryonic cardiac atria and ventricle diversification along anterior-posterior axis in zebrafish. Methods The chemical genetics approach was applied by administrating of zebrafish embryos with 5 × 10^-8 mol/L and 10^-7 mol/L RA at 12.5 hours post fertization (hpf). The cardiac atria and ventricle diversification were monitored by whole-mount in situ hybridization with specific markers, amhc, vmhc, nkx2.5 and nppa genes. Results Whole-mount in situ hybridization with vmhc and amhc RNA probes showed that the vmhc expression cell domain was reduced; meanwhile, amhc expression cell domain was expanded anteriorly in RA treated group. The effect of RA on cardiac diversification became most apparent after 48 hpf. Conclusions The myogenic diversification of the cardiac progenitors along the anterior-posterior axis is altered by adding retinoic acid. Retinoic acid might act as a contributor to atria development, and an inhibitor to ventricle development.