Target Organ Toxicity in Rats After Subchronic Oral Exposure to Soil Extracts Containing a Complex Mixture of...

Area of Science:

• Environmental Toxicology
• In Vitro and In Vivo Toxicology
• Chemical Risk Assessment

Background:

• Complex mixtures of unknown contaminants pose challenges for toxicological risk assessment.
• Traditional methods require extensive animal use and organ screening.
• Legacy-contaminated sites, like pesticide packaging facilities, require effective risk evaluation.

Purpose of the Study:

• To evaluate the toxicity of soil extracts from a legacy-contaminated pesticide site.
• To compare in vitro cytotoxicity screening with in vivo target organ toxicity.
• To identify potential toxicological risks associated with environmental contaminants.

Main Methods:

• Soil extracts were screened using HepG2 cytotoxicity assays.
• Three toxic extracts (A, B, C) were administered to Sprague-Dawley rats via oral gavage for one month.
• Target organ toxicities were assessed through hematology, clinical chemistry, histopathology, cholinesterase activity, and electrocardiography.

Main Results:

• All extracts induced inflammation (increased neutrophils, lymphocytes, alpha-2 macroglobulin) and acute tubular necrosis.
• Extract A reduced plasma cholinesterase activity; Extracts A and B increased hepatic ethoxyresorufin-o-deethylase.
• Extract C caused cardiotoxicity (prolonged QTc) and neurotoxicity (increased brain lipid peroxidation).
• HepG2 cytotoxicity predicted some hydrocarbon toxicities but not neurotoxicity or cardiotoxicity of extract C.

Conclusions:

• In vitro cytotoxicity assays have limitations in predicting complex in vivo toxicities, particularly neurotoxicity and cardiotoxicity.
• Soil extracts from pesticide sites can cause significant systemic inflammation, kidney damage, and specific organ toxicities.
• Further development of in vitro models is crucial for accurate risk assessment of environmental mixtures.