D-tetramethrin induces cardiac looping failure in zebrafish during embryonic development

Area of Science:

• Developmental Biology
• Toxicology
• Cardiovascular Research

Background:

• Cardiac looping is essential for normal heart formation.
• Environmental pollutants, like D-tetramethrin, are linked to congenital heart defects.
• D-tetramethrin is a common insecticide with potential human health impacts.

Purpose of the Study:

• To investigate the effects of D-tetramethrin on zebrafish embryonic heart development.
• To analyze D-tetramethrin-induced oxidative stress and its impact on cardiac gene expression.

Main Methods:

• Zebrafish embryos were exposed to varying concentrations of D-tetramethrin.
• Heart rate and sinus venosus-bulbus arteriosus distance were measured.
• Levels of reactive oxygen species (ROS) and malondialdehyde (MDA) were assessed.
• Enzyme activities of catalase (CAT) and superoxide dismutase (SOD) were analyzed.
• Quantitative PCR (qPCR) was used to examine gene transcription.

Main Results:

• D-tetramethrin exposure reduced heart rate and increased SV-BA distance, indicating cardiac looping failure.
• Increased ROS and MDA levels, with decreased CAT and SOD activity, confirmed oxidative stress.
• Downregulation of key cardiac looping and function genes (e.g., Myh6, Nkx2.5, Gata4) was observed.

Conclusions:

• D-tetramethrin induces cardiac looping failure in zebrafish embryos.
• Oxidative stress and altered gene transcription are key mechanisms underlying D-tetramethrin's cardiotoxicity.
• Findings suggest potential risks of D-tetramethrin exposure to embryonic heart development.