Fatality after deliberate ingestion of the pesticide rotenone: a case report

Evaluation of the Neuroprotective Potential of Sutherlandia frutescens in a Rotenone-Induced Rat Model of Parkinson's Disease

Sutherlandia frutescens (SF) is a plant used traditionally in South Africa for various health conditions, including neurological disorders. Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by the degeneration of dopaminergic neurons in the substantia nigra, resulting in motor symptoms. Rotenone, a pesticide, has been linked to PD-like symptoms in both in vitro and in vivo studies. However, SF-specific effects of SF on PD-related symptoms have not been extensively studied. This study was aimed at investigating the potential neuroprotective effects of SF against rotenone-induced PD using in vivo electrophysiological recordings from the hippocampus and an open-field test to assess motor behavior. Rats were divided into three groups: a control group receiving sunflower oil, a rotenone group treated with rotenone (2.0 mg/kg), and an SF group treated with hydroponically grown SF extract. Electrophysiological recordings from the hippocampus were conducted to assess neuronal activity, and an open-field test was used to evaluate motor behavior. Rats treated with SF exhibited significantly higher motor activity compared to both the sunflower oil and rotenone groups, suggesting an activating effect of SF on motor behavior. In contrast, the rotenone group displayed reduced activity levels and exploratory behavior, highlighting the suppressive impact of rotenone on motor function. These findings suggest that SF modulates hippocampal neuronal activity and may offer neuroprotective benefits against rotenone-induced PD-like symptoms. SF, a plant with traditional medicinal applications, shows potential in modulating motor behavior and hippocampal neuronal activity in a rotenone-induced PD model. Further studies are needed to clarify the underlying mechanisms and evaluate the clinical relevance of SF in PD management.

The neuroprotective effect of 1,25-dyhydroxyvitamin D3 (calcitriol) and probiotics on the rotenone-induced neurotoxicity model in SH-SY5Y cells

This study aimed to investigate the neuroprotective role of probiotics and 1,25-dyhydroxyvitamin D3 (calcitriol) against neurotoxicity on rotenone-induced human neuroblastoma cell line SH-SY5Y. Rotenone was administered to induce neurotoxic effects in SH-SY5Y cells. Calcitriol and probiotics were administered at different concentrations as pre- and post-treatment. The thiazolyl blue tetrazolium bromide (MTT) assay was performed to measure cell viability. Intracellular protein levels of antioxidant enzymes (protein tyrosine kinase (PTK), superoxide dismutase (SOD), glutathione peroxidase (GSH), glutathione reductase (GSR), and catalase (CAT)) were determined by the enzyme-linked immunosorbent assay (ELISA). Rotenone (150 nM) reduced (p < 0.001) cell viability compared to control cells. Single and combined pretreatments with probiotics (0.01 mg/ml, 0.05 mg/ml, and 0.1 mg/ml) and calcitriol (1.25 µM, 2.5 µM, and 5 µM) increased (p < 0.05) cell viability compared to rotenone group. In the pre- and post-treatment design, all treatment groups increased the SOD and GSH levels and decreased the GSR levels compared to rotenone. None of the pretreatments reversed the PTK levels (except probiotics: 0.01 mg/ml). Calcitriol (2.5 µM) increased the CAT levels in pretreatment design, and probiotics (0.05 mg/ml and 0.1 mg/ml) increased CAT levels in post-treatment design compared to rotenone group. Calcitriol and probiotics protect against rotenone-induced neurotoxicity in SH-SY5Y cells by decreasing reactive oxygen species (ROS) and increasing antioxidant enzyme parameters. These neuroprotective effects of calcitriol and probiotics against rotenone-induced dopaminergic neurotoxicity provide an experimental basis for their potential clinical use in the treatment of Parkinson's disease (PD).

Acute rotenone poisoning: A scoping review

Context

Rotenone is a toxic chemical found in various plants, including some used as food. Rotenone poisoning can be fatal and there is no antidote. Mechanistically, rotenone inhibits mitochondrial complex I, leading to reduced ATP production, compensatory glycolytic upregulation and secondary lactate production, and oxidative stress. Our literature review examined acute rotenone poisoning in humans, including exposure scenarios, clinical presentations, and treatments.

Methods

We searched five databases for relevant literature from database inception through the search date: July 12, 2022, pairing controlled vocabulary and keywords for "rotenone" with terms relating to human exposures and outcomes, such as "ingestion," "exposure," and "poisoning." We included all peer-reviewed reports found using the search terms where the full English text was available. Data abstracted included the number, age, weight, and sex of the exposed person(s), country where exposure happened, exposure scenario, ingestion context, estimated dose, clinical features, whether hospitalization occurred, treatments, and outcomes.

Results

After removing non-qualifying sources from 2,631 publications, we identified 11 case reports describing 18 victims, 15 of whom were hospitalized and five died. Most cases occurred in private quarters where victims unknowingly consumed rotenone-containing plants. Vomiting and metabolic acidosis occurred most commonly. Some patients exhibited impaired cardiopulmonary function. Supportive treatment addressed symptoms and included gastric lavage and/or activated charcoal to remove rotenone from the stomach, vasopressors for hypotension, mechanical ventilation for respiratory insufficiency, and sodium bicarbonate for acidosis. Some patients received N-acetylcysteine to counter oxidative stress.

Conclusions

Rotenone poisoning, though rare, can be fatal. Exposure prevention is impractical since rotenone is found in some plants used as food or pesticides. Cases may be under-diagnosed because symptoms are non-specific and under-reported in English-language journals since most cases occurred in non-English speaking countries. Treatments are supportive. Exploring antioxidant therapy in animal models of rotenone poisoning may be indicated considering rotenone's mechanism of toxicity.

A case of rotenone poisoning from ingesting Derris trifoliata Lour. (Tuba fruit/pod) in Malaysia

Derris trifoliata is mainly found in mangrove area in tropical regions and the plant extract is traditionally used for fishing by poisoning. This is the first case report of rotenone poisoning in a child from ingesting Derris trifoliata seed. The child developed altered consciousness, vomiting, hypotension, metabolic acidosis, and acute kidney injury. Species identification of this case requires the collaborative efforts of various agencies. She survived from the poisoning with no neurological sequelae.

Rotenone-Induced Model of Parkinson's Disease: Beyond Mitochondrial Complex I Inhibition

Parkinson's disease (PD) is usually diagnosed through motor symptoms that make the patient incapable of carrying out daily activities; however, numerous non-motor symptoms include olfactory disturbances, constipation, depression, excessive daytime sleepiness, and rapid eye movement at sleep; they begin years before motor symptoms. Therefore, several experimental models have been studied to reproduce several PD functional and neurochemical characteristics; however, no model mimics all the PD motor and non-motor symptoms to date, which becomes a limitation for PD study. It has become increasingly relevant to find ways to study the disease from its slowly progressive nature. The experimental models most frequently used to reproduce PD are based on administering toxic chemical compounds, which aim to imitate dopamine deficiency. The most used toxic compounds to model PD have been 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and 6-hydroxydopamine (6-OHDA), which inhibit the complex I of the electron transport chain but have some limitations. Another toxic compound that has drawn attention recently is rotenone, the classical inhibitor of mitochondrial complex I. Rotenone triggers the progressive death of dopaminergic neurons and α-synuclein inclusions formation in rats; also, rotenone induces microtubule destabilization. This review presents information about the experimental model of PD induced by rotenone, emphasizing its molecular characteristics beyond the inhibition of mitochondrial complex I.

Non-Reproducibility of Oral Rotenone as a Model for Parkinson's Disease in Mice

Oral rotenone has been proposed as a model for Parkinson’s disease (PD) in mice. To establish the model in our lab and study complex behavior we followed a published treatment regimen. C57BL/6 mice received 30 mg/kg body weight of rotenone once daily via oral administration for 4 and 8 weeks. Motor functions were assessed by RotaRod running. Immunofluorescence studies were used to analyze the morphology of dopaminergic neurons, the expression of alpha-Synuclein (α-Syn), and inflammatory gliosis or infiltration in the substantia nigra. Rotenone-treated mice did not gain body weight during treatment compared with about 4 g in vehicle-treated mice, which was however the only robust manifestation of drug treatment and suggested local gut damage. Rotenone-treated mice had no deficits in motor behavior, no loss or sign of degeneration of dopaminergic neurons, no α-Syn accumulation, and only mild microgliosis, the latter likely an indirect remote effect of rotenone-evoked gut dysbiosis. Searching for explanations for the model failure, we analyzed rotenone plasma concentrations via LC-MS/MS 2 h after administration of the last dose to assess bioavailability. Rotenone was not detectable in plasma at a lower limit of quantification of 2 ng/mL (5 nM), showing that oral rotenone had insufficient bioavailability to achieve sustained systemic drug levels in mice. Hence, oral rotenone caused local gastrointestinal toxicity evident as lack of weight gain but failed to evoke behavioral or biological correlates of PD within 8 weeks.

In silico study reveals binding potential of rotenone at multiple sites of pulmonary surfactant proteins: A matter of concern

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Inhalation of rotenone exposes lung surfactant proteins (SP) to this pesticide.

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SP-A and SP-D provides protection from microbial infection.

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SP-B and SP-C maintain structure and respiratory function of lungs.

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Rotenone has potential to bind SPs at multiple sites.

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Such binding can subvert functions of SPs & may invite respiratory ailments.

Rotenone is a broad-spectrum pesticide employed in various agricultural practices all over the world. Human beings are exposed to this chemical through oral, nasal, and dermal routes. Inhalation of rotenone exposes bio-molecular components of lungs to this chemical. Biophysical activity of lungs is precisely regulated by pulmonary surfactant to facilitate gaseous exchange. Surfactant proteins (SPs) are the fundamental components of pulmonary surfactant. SPs like SP-A and SP-D have antimicrobial activities providing a crucial first line of defense against infections in lungs whereas SP-B and SP-C are mainly involved in respiratory cycle and reduction of surface tension at air–water interface. In this study, molecular docking analysis using AutoDock Vina has been conducted to investigate binding potential of rotenone with the four SPs. Results indicate that, rotenone can bind with carbohydrate recognition domain (CRD) of SP-A, N-, and C- terminal peptide of SP-B, SP-C, and CRD of SP-D at multiples sites via several interaction mediators such as H bonds, C–H bonds, alkyl bonds, pi-pi stacked, Van der Waals interaction, and other. Such interactions of rotenone with SPs can disrupt biophysical and anti-microbial functions of SPs in lungs that may invite respiratory ailments and pathogenic infections.

Oxygen in Metabolic Dysfunction and Its Therapeutic Relevance

Significance: In recent years, a number of studies have shown altered oxygen partial pressure at a tissue level in metabolic disorders, and some researchers have considered oxygen to be a (macro) nutrient. Oxygen availability may be compromised in obesity and several other metabolism-related pathological conditions, including sleep apnea-hypopnea syndrome, the metabolic syndrome (which is a set of conditions), type 2 diabetes, cardiovascular disease, and cancer. Recent Advances: Strategies designed to reduce adiposity and its accompanying disorders have been mainly centered on nutritional interventions and physical activity programs. However, novel therapies are needed since these approaches have not been sufficient to counteract the worldwide increasing rates of metabolic disorders. In this regard, intermittent hypoxia training and hyperoxia could be potential treatments through oxygen-related adaptations. Moreover, living at a high altitude may have a protective effect against the development of abnormal metabolic conditions. In addition, oxygen delivery systems may be of therapeutic value for supplying the tissue-specific oxygen requirements. Critical Issues: Precise in vivo methods to measure oxygenation are vital to disentangle some of the controversies related to this research area. Further, it is evident that there is a growing need for novel in vitro models to study the potential pathways involved in metabolic dysfunction to find appropriate therapeutic targets. Future Directions: Based on the existing evidence, it is suggested that oxygen availability has a key role in obesity and its related comorbidities. Oxygen should be considered in relation to potential therapeutic strategies in the treatment and prevention of metabolic disorders. Antioxid. Redox Signal. 35, 642-687.

Using Rotenone to Model Parkinson's Disease in Mice: A Review of the Role of Pharmacokinetics

Rotenone is a naturally occurring toxin that inhibits complex I of the mitochondrial electron transport chain. Several epidemiological studies have shown an increased risk of Parkinson's disease (PD) in individuals exposed chronically to rotenone, and it has received great attention for its ability to reproduce many critical features of PD in animal models. Laboratory studies of rotenone have repeatedly shown that it induces in vivo substantia nigra dopaminergic cell loss, a hallmark of PD neuropathology. Additionally, rotenone induces in vivo aggregation of α-synuclein, the major component of Lewy bodies and Lewy neurites found in the brain of PD patients and another hallmark of PD neuropathology. Some in vivo rotenone models also reproduce peripheral signs of PD, such as reduced intestinal motility and peripheral α-synuclein aggregation, both of which are thought to precede classical signs of PD in humans, such as cogwheel rigidity, bradykinesia, and resting tremor. Nevertheless, variability has been noted in cohorts of animals exposed to the same rotenone exposure regimen and also between cohorts exposed to similar doses of rotenone. Low doses, administered chronically, may reproduce PD symptoms and neuropathology more faithfully than excessively high doses, but overlap between toxicity and parkinsonian motor phenotypes makes it difficult to separate if behavior is examined in isolation. Rotenone degrades when exposed to light or water, and choice of vehicle may affect outcome. Rotenone is metabolized extensively in vivo, and choice of route of exposure influences greatly the dose used. However, male rodents may be capable of greater metabolism of rotenone, which could therefore reduce their total body exposure when compared with female rodents. The pharmacokinetics of rotenone has been studied extensively, over many decades. Here, we review these pharmacokinetics and models of PD using this important piscicide.

Chemically Induced Models of Parkinson's Disease: History and Perspectives for the Involvement of Ferroptosis

Ferroptosis is a newly discovered form of necrotic cell death characterized by its dependency on iron and lipid peroxidation. Ferroptosis has attracted much attention recently in the area of neurodegeneration since the involvement of ferroptosis in Parkinson’s disease (PD), a major neurodegenerative disease, has been indicated using animal models. Although PD is associated with both genetic and environmental factors, sporadic forms of PD account for more than 90% of total PD. Following the importance of environmental factors, various neurotoxins are used as chemical inducers of PD both in vivo and in vitro. In contrast to other neurodegenerative diseases such as Alzheimer’s and Huntington’s diseases (AD and HD), many of the characteristics of PD can be reproduced in vivo by the use of specific neurotoxins. Given the indication of ferroptosis in PD pathology, several studies have been conducted to examine whether ferroptosis plays role in the loss of dopaminergic neurons in PD. However, there are still few reports showing an authentic form of ferroptosis in neuronal cells during exposure to the neurotoxins used as PD inducers. In this review article, we summarize the history of the uses of chemicals to create PD models in vivo and in vitro. Besides, we also survey recent reports examining the possible involvement of ferroptosis in chemical models of PD.

Why All the Fuss about Oxidative Phosphorylation (OXPHOS)?

Certain subtypes of cancer cells require oxidative phosphorylation (OXPHOS) to survive. Increased OXPHOS dependency is frequently a hallmark of cancer stem cells and cells resistant to chemotherapy and targeted therapies. Suppressing the OXPHOS function might also influence the tumor microenvironment by alleviating hypoxia and improving the antitumor immune response. Thus, targeting OXPHOS is a promising strategy to treat various cancers. A growing arsenal of therapeutic agents is under development to inhibit this biological process. This Perspective provides an overview of the structure and function of OXPHOS complexes, their biological functions in cancer, relevant research tools and models, as well as the limitations of OXPHOS as drug targets. We also focus on the current development status of OXPHOS inhibitors and potential therapeutic strategies to strengthen their clinical applications.

Dihydromunduletone Is a Small-Molecule Selective Adhesion G Protein-Coupled Receptor Antagonist

Adhesion G protein-coupled receptors (aGPCRs) have emerging roles in development and tissue maintenance and is the most prevalent GPCR subclass mutated in human cancers, but to date, no drugs have been developed to target them in any disease. aGPCR extracellular domains contain a conserved subdomain that mediates self-cleavage proximal to the start of the 7-transmembrane domain (7TM). The two receptor protomers, extracellular domain and amino terminal fragment (NTF), and the 7TM or C-terminal fragment remain noncovalently bound at the plasma membrane in a low-activity state. We recently demonstrated that NTF dissociation liberates the 7TM N-terminal stalk, which acts as a tethered-peptide agonist permitting receptor-dependent heterotrimeric G protein activation. In many cases, natural aGPCR ligands are extracellular matrix proteins that dissociate the NTF to reveal the tethered agonist. Given the perceived difficulty in modifying extracellular matrix proteins to create aGPCR probes, we developed a serum response element (SRE)-luciferase-based screening approach to identify GPR56/ADGRG1 small-molecule inhibitors. A 2000-compound library comprising known drugs and natural products was screened for GPR56-dependent SRE activation inhibitors that did not inhibit constitutively active Gα13-dependent SRE activation. Dihydromunduletone (DHM), a rotenoid derivative, was validated using cell-free aGPCR/heterotrimeric G protein guanosine 5'-3-O-(thio)triphosphate binding reconstitution assays. DHM inhibited GPR56 and GPR114/ADGRG5, which have similar tethered agonists, but not the aGPCR GPR110/ADGRF1, M3 muscarinic acetylcholine, or β2 adrenergic GPCRs. DHM inhibited tethered peptide agonist-stimulated and synthetic peptide agonist-stimulated GPR56 but did not inhibit basal activity, demonstrating that it antagonizes the peptide agonist. DHM is a novel aGPCR antagonist and potentially useful chemical probe that may be developed as a future aGPCR therapeutic.

Hormetic effect of rotenone in primary human fibroblasts

BACKGROUND

Rotenone inhibits the electron transfer from complex I to ubiquinone, in this way interfering with the electron transport chain in mitochondria. This chain of events induces increased levels of intracellular reactive oxygen species, which in turn can contribute to acceleration of telomere shortening and induction of DNA damage, ultimately resulting in aging. In this study, we investigated the effect of rotenone treatment in human fibroblast strains.

RESULTS

For the first time we here describe that rotenone treatment induced a hormetic effect in human fibroblast strains. We identified a number of genes which were commonly differentially regulated due to low dose rotenone treatment in fibroblasts independent of their cell origin. However, these genes were not among the most strongly differentially regulated genes in the fibroblast strains on treatment with rotenone. Thus, if there is a common hormesis regulation, it is superimposed by cell strain specific individual responses. We found the rotenone induced differential regulation of pathways common between the two fibroblast strains, being weaker than the pathways individually regulated in the single fibroblast cell strains. Furthermore, within the common pathways different genes were responsible for this different regulation. Thus, rotenone induced hormesis was related to a weak pathway signal, superimposed by a stronger individual cellular response, a situation as found for the differentially expressed genes.

CONCLUSION

We found that the concept of hormesis also applies to in vitro aging of primary human fibroblasts. However, in depth analysis of the genes as well as the pathways differentially regulated due to rotenone treatment revealed cellular hormesis being related to weak signals which are superimposed by stronger individual cell-internal responses. This would explain that in general hormesis is a small effect. Our data indicate that the observed hormetic phenotype does not result from a specific strong well-defined gene or pathway regulation but from weak common cellular processes induced by low levels of reactive oxygen species. This conclusion also holds when comparing our results with those obtained for C. elegans in which the same low dose rotenone level induced a life span extending, thus hormetic effect.

Vascular damage mediates neuronal and non-neuronal pathology following short and long-term rotenone administration in Sprague-Dawley rats

Even though rotenone has been used extensively in recent years to produce a model of Parkinson disease in rats, its systemic effects either on neurons apart from dopaminergic structures or non-neuronal tissues have not been elucidated well. In our present study, 30 adult Sprague-Dawley rats were divided into three even groups. A short-term rotenone-treated group received 10 mg/kg b.w. rotenone daily for 7 days. The long-term rotenone-treated group received 3 mg/kg b.w. rotenone daily for 30 days. The control group received vehicle only and were kept 5 rats each in parallel to both short- and long-term rotenone treated groups. It was found that short-term rotenone treatment produced marked vascular damages associated with ischemic neuronal degeneration particularly in the thalamus, cerebellum and nucleus dentatus. In long-term rotenone-treated group, vascular changes were less severe and neuronal degeneration was associated with mild microglial proliferation and astrocytosis. Non-neuronal pathology as the result of short-term rotenone exposure consisted of degeneration and necrosis of seminiferous tubular epithelia with formation of spermatide multinucleate giant cells. On the other hand, long-term rotenone treatment did not affect testicles and only caused sinusoidal dilatation in the liver, myocardial degeneration in the heart and interstitial hemorrhages in the kidneys and lungs. In conclusions, damage to blood vasculature by rotenone appeared mediating neuronal and non-neuronal pathology in Sprague-Dawley rats. This effect might provide new insights for ethiopathogenesis of neurodegenerative diseases and contributes to the understanding of hemorrhagic stroke.

Suicide attempt by ingestion of rotenone-containing plant extracts: one case report in French Guiana

INTRODUCTION

Several species of plants in the Fabaceae family are traditionally used for poison fishing because they contain ichthyotoxic rotenoids. In French Guiana two species of Fabaceae belonging to Lonchocarpus genus with a toxic rotenone effect are used for such ancestral practices. Rotenone is of low toxicity for humans when it is diluted, but its neurotoxicity at higher concentrations is well known to users.

CASE REPORT

The purpose of this article is to describe a case of self-poisoning by an 86-year-old woman who ingested a bowl of mashed ichthyotoxic plants. Despite early onset of severe symptoms, the patient regained consciousness and resumed normal breathing within a few hours with only symptomatic treatment.

CONCLUSION

The clinical pattern observed in this patient (onset of digestive manifestations followed quickly by loss of conscience and respiratory insufficiency) is in agreement with the few poisonings reported in the literature involving other Fabaceae species containing rotenoids in Asia or involving concentrated rotenone used in insecticides. In patients, who survive the initial phase, symptoms usually regress quickly.