Early developmental lead exposure disrupts skeletal development in zebrafish

Area of Science:

• Environmental Toxicology
• Developmental Biology
• Skeletal Biology

Background:

• Lead (Pb) is a toxic environmental pollutant with known effects on multiple organ systems.
• However, its specific impact on skeletal development and the underlying mechanisms are not well understood.

Purpose of the Study:

• To investigate the developmental toxicity of lead (Pb) on skeletal development in zebrafish (Danio rerio) embryos.
• To elucidate the mechanisms by which Pb affects bone and cartilage formation.

Main Methods:

• Zebrafish embryos were exposed to various concentrations of lead (II) acetate (PbAc) for 7 days.
• Morphological abnormalities, survival rates, and heart rate were assessed.
• Alcian blue, Alizarin red, and Calcein staining were used to evaluate cartilage and bone development.
• Enzyme activities (ALP, ACP), antioxidant capacity (SOD), and gene expression (Bmp2, Col2a1, Runx2, Wnt16, Sparc) were analyzed.

Main Results:

• Pb exposure caused dose-dependent morphological abnormalities, increased mortality, and reduced hatching rates.
• Craniofacial cartilage development and skeletal mineralization were significantly impaired.
• Pb suppressed alkaline phosphatase (ALP) and acid phosphatase (ACP) activities, reduced antioxidant capacity, and downregulated key osteogenesis-related genes.

Conclusions:

• Lead exposure significantly disrupts zebrafish skeletal development by interfering with cartilage formation and bone mineralization.
• Mechanisms include altered phosphatase activity, compromised antioxidant defense, and dysregulated expression of critical bone development genes.
• This research provides insights into heavy metal toxicity in vertebrate development with implications for human health risk assessment.