Postmortem sampling time effect on toxicity biomarkers in rats exposed to an acute lethal methomyl dose

Shreen D Nusair; Mohammad Ananbeh; Aref Zayed; Mohammad I Ahmad; Nidal A Qinna

doi:10.1016/j.toxrep.2022.08.010

Postmortem sampling time effect on toxicity biomarkers in rats exposed to an acute lethal methomyl dose

Toxicol Rep. 2022 Aug 24:9:1674-1680. doi: 10.1016/j.toxrep.2022.08.010. eCollection 2022.

Authors

Shreen D Nusair¹, Mohammad Ananbeh², Aref Zayed³, Mohammad I Ahmad⁴, Nidal A Qinna⁴

Affiliations

¹ Department of Clinical Pharmacy, Faculty of Pharmacy, Jordan University of Science and Technology, Irbid, Jordan.
² Department of Forensic Medicine Toxicology and Forensic Sciences, Faculty of Medicine, Jordan University of Science and Technology, Irbid, Jordan.
³ Department of Medicinal Chemistry and Phramacognosy, Jordan University of Science and Technology, Irbid, Jordan.
⁴ University of Petra Pharmaceutical Center (UPPC), Faculty of Pharmacy & Medical Sciences, University of Petra, Amman, Jordan.

Abstract

Regulations often are imposing long postmortem times before autopsy leading to certain toxicity-unrelated changes in biomarkers, which in turn may affect the reliability of toxicity evaluation during forensic investigations. Since methomyl pesticide shows significant toxicity and is frequently encountered in poisoning cases, the current study evaluated different parameters in methomyl intoxicated rats at three different postmortem intervals (Hour 0, Hour 3 and Hour 6). Eighteen adult Sprague Dawley rats were poisoned with methomyl to simulate actual methomyl poisoning cases. The time of death was assigned as Hour 0. The animals were divided into 3 groups (n = 6) to collect blood and tissue samples at the selected time points. Body weight, relative organ weight, protein concentration, methomyl concentration and acetylcholinesterase activity (AChE) were assessed in blood and different tissues (liver, spleen, kidney, brain, eye, and bone marrow) to evaluate the effect of postmortem sampling time. Outcomes revealed significant decreases in methomyl concentration in blood and bone marrow with advanced sampling time (P < 0.001). Similarly, there were significant reductions in AChE activity in the kidney (P < 0.01), while the enzyme activity significantly increased in brain samples (P < 0.05). Findings illustrated the importance of sampling time in toxicity studies because it could alter experimental results and impact consequent interpretations, as well as it may alter postmortem biomarkers in related forensic cases.

Keywords: ACUC, Animal Care Committee; AChE, Acetylcholinesterase activity; ANOVA, Analysis of Variance; Acetylcholinesterase, Sampling time; ChE, Cholinesterase; ESI, Electrospray ionization; GC, Gas chromatography; IS, Internal standard; JCIA, Joint Commission International Accreditation; JFDA, Jordan Food and Drug Administration; LC, Liquid chromatography; LC-MS/MS; LC-MS/MS, Liquid Chromatography-Tandem Mass Spectrometry; LOD, Limit of detection; LOQ, Limit of quantitation; M ± SD, Mean ± standard deviation; MRM, Multiple reaction monitoring; Methomyl; PBS, Phosphate-Buffered Saline; PRC, Pharmaceutical Research Center; Pesticides; SPE; Toxicity; UPPC, University of Petra Pharmaceutical Center; US EPA, United States Environmental Protection Agency; bwt, Body weight; m/z, Mass-to-charge ratio.