Zebrafish embryos as a teratogenicity screening tool to reduce potential birth defects

Area of Science:

• Developmental toxicology
• Comparative toxicology
• Embryology

Background:

• Teratogens are critical in causing birth defects, necessitating robust screening methods.
• Existing screening methods require optimization for accuracy and efficiency.
• Zebrafish embryos offer a promising model for early-stage toxicological assessment.

Purpose of the Study:

• To develop and optimize a zebrafish embryo-based platform for teratogenicity screening.
• To validate the platform's efficacy by comparing results with established clinical and animal data.
• To establish reliable parameters for teratogenicity risk assessment using zebrafish.

Main Methods:

• Zebrafish embryos (6–8 hours post-fertilization) were exposed to 19 test solutions (9 teratogens, 10 non-teratogens) in 96-well plates.
• Mortality and morphological abnormalities were assessed at 48, 72, and 96 hours post-fertilization.
• Half-lethal concentration (LC50) and half-effective concentration (EC50) were calculated to determine the teratogenicity index (TI = LC50/EC50).

Main Results:

• Eight of the tested compounds were identified as teratogenic (TI > 3), and nine as non-teratogenic (TI < 3).
• Extended exposure to 96 hours post-fertilization improved assessment accuracy.
• Observed zebrafish embryo phenotypes correlated with known teratogenic malformations in clinical and animal studies.

Conclusions:

• The optimized zebrafish embryo platform with a TI threshold of 3 provides reliable teratogenicity risk assessment.
• This method, utilizing a 6–8 hours post-fertilization to 96 hours post-fertilization exposure window, is effective for identifying teratogenic substances.
• The findings support the use of zebrafish embryos as a valuable tool in developmental toxicology and birth defect research.