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Updated: Jul 20, 2025
An In Vitro Approach to Study Mitochondrial Dysfunction: A Cybrid Model
Published on: March 9, 2022
Cell-Free DNA as a Biomarker in a Rodent Model of Chlorpyrifos Poisoning Causing Mitochondrial Dysfunction
Shih-Han Kao1, Frances S Shofer2, John C Greenwood2
1The Children's Hospital of Philadelphia, The Resuscitation Science Center, Philadelphia, PA, 19104, USA.
Introduction:
Organophosphates (OPs) are a major public health problem worldwide due to ease of access and high toxicity lacking effective biomarkers and treatment. Cholinergic agents such as OPs and carbamates are responsible for many pesticide-related deaths. While the inhibition of AChE is thought to be the main mechanism of injury, there are other important pathways that contribute to the overall toxicity of OPs such as mitochondrial dysfunction. An existing gap in OP poisoning are biomarkers to gauge severity and prognosis. Cell-free DNA (cfDNA) are novel biomarkers that have gained increased attention as a sensitive biomarker of disease with novel use in acute poisoning. This study investigates alterations in cerebral mitochondrial function in a rodent model of chlorpyrifos poisoning with the use of cfDNA as a potential biomarker.
Methods:
Twenty rodents were divided into two groups: Control (n = 10) and Chlorpyrifos (n = 10). Chlorpyrifos was administered through the venous femoral line with a Harvard Apparatus 11 Elite Syringe pump (Holliston, MA, USA) at 2 mg/kg. Animals were randomized to receive chlorpyrifos versus the vehicle (10% DMSO) for 60 min which would realistically present an acute exposure with continued absorption. At the end of the exposure (60 min), isolated mitochondria were measured for mitochondrial respiration along with measures of acetylcholinesterase activity, cfDNA, cytokines and western blot.
Results:
The Chlorpyrifos group showed a significant decrease in heart rate but no change in the blood pressure. There was a significant increase in bulk cfDNA concentrations and overall decrease in mitochondrial respiration from brain tissue obtained from animals in the Chlorpyrifos group when compared to the Control group with no difference in acetylcholinesterase activity. In addition, there was a significant increase in both IL-2 and IL-12 in the Chlorpyrifos group.
Conclusions:
In our study, we found that the total cfDNA concentration may serve as a more accurate biomarker of OP exposure compared to acetylcholinesterase activity. In addition, there was an overall decrease in cerebral mitochondrial function in the Chlorpyrifos group when compared to the Control group.
Insights
Organophosphate poisoning can be assessed using cell-free DNA (cfDNA) as a biomarker. This study found cfDNA levels increased and mitochondrial function decreased in rodent models of chlorpyrifos exposure.
Area of Science:
- Toxicology
- Biochemistry
- Neuroscience
Background:
- Organophosphates (OPs) are toxic pesticides causing public health issues.
- Current biomarkers for OP poisoning, like acetylcholinesterase activity, have limitations.
- Mitochondrial dysfunction is an understudied contributor to OP toxicity.
Purpose of the Study:
- To investigate cerebral mitochondrial dysfunction in chlorpyrifos poisoning.
- To evaluate cell-free DNA (cfDNA) as a potential biomarker for OP poisoning severity.
Main Methods:
- Rodent models were exposed to chlorpyrifos (2 mg/kg) or a vehicle control for 60 minutes.
- Mitochondrial respiration, acetylcholinesterase activity, cfDNA, and cytokine levels were measured.
- Western blot analysis was also performed on brain tissue.
Main Results:
- Chlorpyrifos exposure led to decreased heart rate but unchanged blood pressure.
- Significant increases in cfDNA concentration and pro-inflammatory cytokines (IL-2, IL-12) were observed.
- Mitochondrial respiration in brain tissue was significantly reduced in the chlorpyrifos group, with no change in acetylcholinesterase activity.
Conclusions:
- Total cfDNA concentration may be a more sensitive biomarker for OP exposure than acetylcholinesterase activity.
- Chlorpyrifos poisoning is associated with impaired cerebral mitochondrial function.
- cfDNA shows promise as a novel biomarker for assessing acute poisoning severity.
