Developmental Toxicity

Assay Description

The developmental toxicity model investigates the impact of toxic substances on zebrafish embryos during early stages of development, focusing on malformations and delayed development.

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Testing Method: Zebrafish embryos are exposed to the toxic compound, and developmental milestones such as heart formation, body axis development, and organogenesis are observed.

Pathology

• Malformations: Defects in major organs (heart, brain, eyes), malformed body parts (tail, yolk sac), and growth inhibition.

• Delayed Development: Slower progression through developmental stages, including delayed hatching or malformations of the axial skeleton.

Biomarkers

• Gene Expression of Developmental Pathways: Assessment of key genes involved in embryogenesis (e.g., hox genes, sonic hedgehog) to evaluate developmental disruptions.

• Reactive Oxygen Species (ROS): Elevated ROS levels in embryos indicate oxidative stress caused by toxic exposure.

Screening Endpoints

• Embryonic Malformations: Abnormalities in organogenesis, skeletal structure, or pigmentation.

• Developmental Delays: Delays in hatching, reduced body length, or abnormal swimming behavior.

• Growth Defects: Reduced growth, small body size, or lack of development of organs (heart, eyes, liver).