Cylindrospermopsin impairs zebrafish (Danio rerio) embryo development

Area of Science:

• Environmental toxicology
• Developmental biology
• Aquatic toxicology

Background:

• Cyanotoxins, like cylindrospermopsin (CYN), are global water contaminants impacting health.
• CYN's effects on mammals are known, but its toxicity mechanisms in other vertebrates remain unclear.
• Zebrafish larvae offer a model to study developmental toxicity in aquatic organisms.

Purpose of the Study:

• To characterize the developmental effects of CYN in zebrafish larvae.
• To investigate CYN's impact on gene expression related to oxidative stress, osmoregulation, and thyroid function.
• To establish a threshold for CYN's osmoregulatory effects.

Main Methods:

• Zebrafish larvae were exposed to a range of CYN concentrations (0-2000 μg/L).
• Morphometric analysis assessed survival, hatching, growth, and developmental abnormalities.
• Gene expression analysis investigated oxidative stress, osmoregulation, and thyroid function markers.

Main Results:

• CYN exposure led to reduced growth and increased abnormalities (e.g., edema, swim bladder absence).
• CYN altered thyroid function genes (tr1a, dio1, dio3) and increased oxidative stress markers (hsp70, ahr1a, cyp1a, gpx, cat).
• Osmoregulation genes (aqp3a, dab2) were affected, with a threshold of 10 μg/L for CYN's impact.

Conclusions:

• CYN exposure causes significant developmental and physiological effects in zebrafish embryos.
• Environmentally relevant CYN concentrations can disrupt critical biological functions.
• Zebrafish serve as a valuable model for assessing cyanotoxin developmental toxicity.