Chemical-induced heart defects using a transgenic zebrafish model.

Area of Science:

• Developmental Biology
• Toxicology
• Genetics

Background:

• Congenital heart defects (CHDs) are prevalent birth defects influenced by genetic and environmental factors.
• Identifying environmental teratogens is critical for preventing chemical-induced CHDs.
• High-throughput screening is needed to assess the cardiovascular teratogenicity of numerous chemicals.

Purpose of the Study:

• To develop and validate transgenic zebrafish reporter lines for high-throughput screening of chemical teratogens.
• To investigate the impact of known teratogens on early cardiovascular development in real-time.
• To identify critical developmental windows susceptible to teratogenic exposure.

Main Methods:

• Creation of three transgenic zebrafish lines (myl7:EGFP, kdrl:MRFP, gata1:MKate2) for visualizing heart development and function.
• Real-time imaging of zebrafish embryos exposed to known mammalian teratogens.
• Analysis of cardiac morphogenesis, progenitor marker expression, and blood flow dynamics.

Main Results:

• Teratogens caused significant cardiac malformations, including abnormal heart tube formation, looping, and chamber size.
• Disruption of cardiac progenitor marker expression indicated impaired progenitor development.
• Functional defects, such as reduced blood flow, were observed via real-time imaging.
• Susceptibility to teratogens was highest during early development (4-48 hours post-fertilization).

Conclusions:

• Transgenic zebrafish models provide an effective platform for high-throughput teratogenicity testing.
• These models enable mechanistic analysis of chemical-induced heart defects.
• The developed zebrafish system can aid in identifying and mitigating risks associated with CHDs.