In vivo localization and postmortem stability of benzo[a]pyrene-DNA adducts.

Area of Science:

• Environmental Toxicology
• Molecular Carcinogenesis
• Biomarker Analysis

Background:

• Polycyclic aromatic hydrocarbon (PAH)-DNA adducts are critical in gastrointestinal cancer development.
• Precise localization and postmortem stability of PAH-DNA adducts in the gastrointestinal tract remain largely unknown.
• Understanding these factors is crucial for assessing exposure and cancer risk.

Purpose of the Study:

• To determine the precise localization of benzo[a]pyrene-DNA (BPdG) adducts within the mouse gastrointestinal tract.
• To investigate the long-term stability of BPdG adducts in postmortem tissues stored at 4°C.
• To evaluate the feasibility of studying PAH-DNA adducts in wildlife from colder climates.

Main Methods:

• Mice were injected with benzo[a]pyrene (BP), a carcinogenic PAH.
• Tissues were collected at various time points post-euthanasia and stored at 4°C.
• Immunohistochemistry (IHC) and quantitative assays (BPDE-DNA CIA, HPLC-ES-MS/MS) were used to detect and quantify BPdG adducts.

Main Results:

• BPdG adducts were localized in forestomach basal cells (including stem cells) for up to 7 days and in proximal small intestine villus epithelium for up to 12 hours.
• Quantitative assays showed BPdG adduct levels were stable in small intestine, forestomach, and lung tissues stored for up to 7 days postmortem.
• IHC and quantitative methods showed good correlation (P=0.0001).

Conclusions:

• This study precisely localized BPdG adducts in the mouse gastrointestinal tract, identifying specific cell types and durations of detection.
• PAH-DNA adducts exhibit significant stability in postmortem tissues, enabling extended study periods.
• The findings support the examination of PAH-DNA adducts in wildlife exposed to environmental contaminants, even in colder regions.