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2,3,7,8-Tetrachlorodibenzo-p-dioxin-mediated oxidative stress in CYP1A2 knockout (CYP1A2-/-) mice
B P Slezak1, J J Diliberto, L S Birnbaum
1Curriculum in Toxicology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
Abstract:
The objective of the study was to compare alterations in indicators of oxidative stress following 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure in cytochrome P4501A2 (CYP1A2) knockout mice and their parental lineage strains (C57BL/6N and 129/Sv). This study will aid in determining the role, if any, of CYP1A2 in TCDD-mediated oxidative stress. Formation of thiobarbituric acid-reactive substances (TBARS) as a measurement of lipid peroxidation, production of reactive oxygen species (ROS) via the in vitro reduction of cytochrome c in tissue homogenate, and changes in the biochemical antioxidant glutathione were monitored to determine oxidative stress 7 days following a single oral dose of 25 microg TCDD/kg. TBARS, reduction of cytochrome c, and changes in glutathione demonstrated a similar response in CYP1A2 knockout and parental strains. These data suggest that CYP1A2 does not play a critical role in the acute oxidative stress response following TCDD exposure.
Insights
Cytochrome P4501A2 (CYP1A2) does not appear critical for oxidative stress caused by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Studies in knockout mice show similar responses to TCDD exposure compared to normal strains.
Area of Science:
- Toxicology
- Biochemistry
- Genetics
Background:
- 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a potent environmental toxicant.
- Oxidative stress is a key mechanism in TCDD toxicity.
- Cytochrome P4501A2 (CYP1A2) is involved in xenobiotic metabolism.
Purpose of the Study:
- To investigate the role of CYP1A2 in TCDD-induced oxidative stress.
- To compare oxidative stress markers in CYP1A2 knockout mice and their parental strains following TCDD exposure.
Main Methods:
- Mice (CYP1A2 knockout, C57BL/6N, 129/Sv) were administered a single oral dose of TCDD (25 microg/kg).
- Oxidative stress was assessed 7 days post-exposure by measuring thiobarbituric acid-reactive substances (TBARS) for lipid peroxidation.
- Reactive oxygen species (ROS) production and glutathione levels were quantified.
Main Results:
- TBARS levels, ROS production, and glutathione changes showed similar responses in CYP1A2 knockout and parental strains.
- No significant differences in oxidative stress indicators were observed between the groups.
Conclusions:
- CYP1A2 does not play a critical role in the acute oxidative stress response to TCDD.
- The findings suggest alternative pathways mediate TCDD-induced oxidative damage.