Investigating the Effects of Echium amoenum on Nkx2-5, ApoE, and Tbx5 Gene Expression in Zebrafish Cardiovascular Embryo

Abstract

Cardiovascular diseases (CVDs) remain the leading cause of death globally and on average take 30% of all deaths around the world. Such alarming statistics mandate that an effort be made to find appropriate preventive and therapeutic strategies. The present study characterized the effects of Echium amoenum extract, a traditional plant with known antioxidant properties, in developing the cardiovascular system and investigated these effects on expression levels of Nkx2-5, ApoE, and Tbx5 genes responsible for heart development using zebrafish as an animal model.

In the present work, dry Echium amoenum extract was obtained using an alcoholic extraction procedure, and different concentrations of this mixture were used to treat zebrafish embryos at 24 hpf (hours post-fertilization), 48 hpf, as well as 72 hfp stages.  Morphological assessments revealed that concentrations above 62.5 µg/mL led to significant abnormalities and increased mortality rates, with an LD50 determined at 101 µg/mL.

Gene expression analysis indicated that the lower concentrations of the extract significantly stimulated Nkx2-5, ApoE, and Tbx5 gene expressions as candidates involved in cardiac differentiation and lipid metabolism. In contrast, expression levels of these genes were reduced at higher concentrations suggesting a dose-dependent effect. The LD50 concentration was not associated with any observable heart toxicity, and histological evaluation revealed no signs of injury in exposed hearts when compared to controls; cellular architecture remained intact and all standard features were present throughout the subendocardial region (comprised mainly by cardiomyocytes, or endocardium/substrate) except for some cells demonstrating vacuolization.

These findings highlight the therapeutic efficacy of Echium amoenumas a natural antioxidant and its cardio-protective effects. This study emphasizes the requirement of mechanistic studies supporting its effects and the development of safe dose for future clinical trials in cardiovascular diseases control.