Embryotoxicity Caused by DON-Induced Oxidative Stress Mediated by Nrf2/HO-1 Pathway

Area of Science:

• Toxicology
• Molecular Biology
• Developmental Biology

Background:

• Deoxynivalenol (DON), a trichothecene mycotoxin, is prevalent in grains and linked to various toxicities.
• DON exposure can lead to cytotoxicity, immunotoxicity, genotoxicity, teratogenicity, and carcinogenicity.
• The Nrf2/HO-1 pathway is a key regulator of cellular response to oxidative stress.

Purpose of the Study:

• To investigate the hypothesis that DON induces embryotoxicity by altering Nrf2/HO-1 pathway expression.
• To examine the role of oxidative stress in DON-induced embryotoxicity.
• To explore the dose- and time-dependent effects of DON on the Nrf2/HO-1 pathway.

Main Methods:

• Experiments were conducted using C57BL/6 mice and BeWo cell lines.
• Mice were administered varying doses of DON during pregnancy (0-5.0 mg/kg/day).
• BeWo cells were treated with DON at different concentrations (0-50 nM) and time points (3, 12, 24 h).
• Reactive oxygen species (ROS) levels and Nrf2/HO-1 pathway expression were analyzed.

Main Results:

• DON treatment in pregnant mice led to ROS accumulation in the placenta, causing embryotoxicity.
• The Nrf2/HO-1 pathway was upregulated by ROS in placental cells as a protective response.
• In BeWo cells, DON exposure showed dose- and time-dependent effects on ROS and HO-1 expression.
• A 'threshold effect' was observed where moderate HO-1 increase was protective, but excessive levels exacerbated oxidative damage.

Conclusions:

• Oxidative stress is a critical molecular mechanism underlying DON-induced embryotoxicity.
• The Nrf2/HO-1 pathway plays a significant role in mitigating DON-induced oxidative damage.
• The 'threshold effect' of the Nrf2/HO-1 pathway is important in the context of DON toxicity.