Dioxin causes a sustained oxidative stress response in the mouse

Area of Science:

• Environmental toxicology
• Molecular toxicology
• Biochemistry

Background:

• Dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin; TCDD) is a potent environmental toxicant and aromatic hydrocarbon receptor (AHR) agonist.
• While TCDD is not directly genotoxic, it can induce mutations and oxidative stress in experimental models.
• The precise mechanisms and duration of dioxin-induced oxidative stress in mice remain poorly characterized.

Purpose of the Study:

• To investigate the prolonged oxidative stress response to TCDD exposure in female C57BL/6J mice.
• To quantify the duration of TCDD-induced changes in oxidative stress biomarkers.

Main Methods:

• Female C57BL/6J mice were administered 5 micrograms TCDD per kilogram body weight for 3 consecutive days.
• Hepatic oxidized glutathione levels were measured at various time points post-treatment.
• Urinary 8-hydroxydeoxyguanosine levels were assessed at 8 weeks after TCDD exposure.

Main Results:

• TCDD treatment led to a sustained 2-fold increase in hepatic oxidized glutathione levels, persisting for at least 8 weeks.
• Urinary 8-hydroxydeoxyguanosine levels remained elevated approximately 20-fold at 8 weeks post-TCDD exposure.
• These findings indicate a prolonged and significant oxidative stress response following dioxin exposure.

Conclusions:

• Dioxin exposure induces a striking and prolonged oxidative stress response in mice.
• The sustained elevation of oxidative stress markers suggests chronic DNA damage and potential promutagenic effects.
• This study highlights the long-lasting impact of dioxin on cellular oxidative balance.