Developmental reelin expression and time point-specific alterations from lead exposure in zebrafish

Area of Science:

• Neuroscience
• Developmental Biology
• Toxicology

Background:

• Reelin (RELN) is a glycoprotein crucial for neuronal development and function.
• Previous studies indicated altered RELN expression in zebrafish exposed to lead (Pb).
• RELN is implicated in neurodevelopmental disorders, making it a potential target for Pb neurotoxicity.

Purpose of the Study:

• To investigate the impact of developmental lead exposure on Reelin (RELN) gene expression in zebrafish.
• To determine the specific concentrations and developmental time points affected by lead exposure.

Main Methods:

• In situ hybridization and quantitative PCR (qPCR) were used to analyze RELN expression.
• Zebrafish embryos were exposed to varying lead concentrations (10, 50, 100 ppb) at multiple developmental stages (24-96 hours post-fertilization).
• Brain morphology and apoptosis were assessed at the highest exposure concentration.

Main Results:

• RELN expression was primarily observed in the telencephalon, midbrain, hindbrain, and spinal cord.
• Lead exposure (100 ppb) significantly decreased RELN expression at 60 hours post-fertilization.
• No significant changes in brain length or apoptotic cell numbers were observed at the highest lead concentration.

Conclusions:

• Developmental lead exposure can decrease RELN expression in zebrafish embryos at concentrations below those causing overt morphological changes.
• This suggests a sensitive, early-stage neurodevelopmental effect of lead toxicity.
• The findings highlight RELN as a potential biomarker for early lead-induced neurotoxicity.