Effect of Fipronil Exposure on Hematological Aspects of Rhesus Monkeys (Macaca mulatta): Risk and Toxicity Assessment in Agro-Workers

Background

Fipronil (FPN) is a broad-spectrum phenylpyrazole insecticide, widely used in agriculture and veterinary medicine. Published research on FPN toxicity has established the fact that its inhalation or dermal exposure may lead to very serious clinical outcomes in non-target animals. In line to its exposure and toxicity related damage, FPN has been investigated in many invertebrates, however, its exposure-related noxiousness is less reported in higher animals.

Objective

To assess the FPN-induced effects to agro-workers in the field, in the present study, we used physiological human surrogates, adult rhesus monkeys as models.

Method

We exposed well habituated, chair restraint adult rhesus monkeys with a field spray concentration of FPN (0.3 mg/1 mL distilled water) through an inhalation route in the closed system. Animals were divided into control and treatment groups, each containing three animals. Inflammatory and hematological effects were determined by evaluating the kidney and liver biomarker enzymes; serum creatinine and alanine transaminase (ALT), aspartate transaminase (AST) levels respectively.

Results

Our findings reveal that FPN treated monkeys show significantly increased levels of ALT (p = 0.000461), AST (p = 0.0681) and creatinine (p = 0.00656) as compared to the control group. Furthermore, significant differences of red blood cells (RBCs) (p = 0.0139) and white blood cells (WBCs) (p = 0.00642) were also observed in the treated and control group monkeys which reflect strong toxic effects on the blood cells.

Conclusion

Our findings demonstrate that FPN exposure is very toxic to higher animals and causes severe damage to the liver and kidneys along with other clinical problems. The study highlights the effect and impact of passive inhalation of insecticides in intentionally carefree agro-workers and raises the concern of public awareness toward pesticides use.

Novel fast pesticides extraction (FaPEx) strategy coupled with UHPLC-MS/MS for rapid monitoring of emerging pollutant fipronil and its metabolite in food and environmental samples

In this work, we demonstrated a new, environmental-friendly and effective sample preparation strategy named 'in-syringe-assisted fast pesticides extraction (FaPEx)' technique coupled with LC-MS/MS for the rapid identification and monitoring of emerging pollutant fipronil and its metabolite fipronil sulfone in chicken egg and environmental soil samples. FaPEx strategy comprising of two simple steps. Firstly, the sample was placed in the syringe and extracted using low-volume acetonitrile with NaCl and anhydrous MgSO₄ salts. Secondly, the extractant was passed through in-syringe-based solid-phase extraction (SPE) kit containing cleanup sorbents and salt combinations (C18, primary secondary amine, and anhydrous MgSO₄) for the cleanup process. Then, the obtained clean extractant was injected into LC-MS/MS for the quantification of target analytes. Various important parameters influencing the FaPEx performances, such as solvent type, salt type, salt amount, sorbent type, and amount, were examined and optimized. The method validation results showed excellent linearity with high correlation coefficients were ≥ 0.99. The estimated LODs were between 0.05-0.07 μg/kg, and LOQs ranged between 0.1-0.25 μg/kg for target analytes in both egg and soil sample matrices, and precision values were ≤7.90%. The developed method was applied to commercial chicken egg samples and environmental soil samples analysis. Spiked recoveries ranged between 88.75-110.91% for egg samples with RSDs ≤7.42% and 82.47-107.46% for soil samples with RSDs <7.37%. These results proved that the developed sample preparation method is a simple, fast, green, low-cost, and efficient method for the analysis of fipronil and its metabolites in food and environmental samples. Thus, this method can be applied as an alternative analytical methodology in routine and standard food and environmental testing laboratories.

A novel electrochemical sensor for the detection of fipronil and its toxic metabolite fipronil sulfone using TiO2-polytriazine imide submicrostructured composite as an efficient electrocatalyst

For the first time, a simple and sensitive electrochemical sensor based on a screen printed electrode (SPE) modified with titanium dioxide (TiO₂) and polytriazine imide submicrostructured composite (TiO₂-PTI) has been developed for the simultaneous detection of fipronil (FIP) and its toxic metabolite fipronil sulfone (FIP-S). The submicrostructured composite material based on TiO₂ and PTI was obtained by simple hydrothermal treatment of the Ti peroxocomplexes in the presence of pristine. This carbon nitride allotrope has better crystallinity and conductivity than its graphitic analog. It was found that the TiO₂-PTI submicrostructured composite enhanced the electrochemical sensing of the SPE electrode towards FIP and its metabolite FIP-S in 0.1 M Britton-Robinson buffer (pH 10) at the oxidation potentials of 0.82 V and 0.94 V, respectively. In addition, it showed good stability and reproducibility for the determination of both analytes. Under optimal conditions, the peak currents by square wave voltammetry were found to vary linearly with FIP and FIP-S concentrations in the range from 0.01 to 10 μM and from 10 to 50 μM, with a detection limit of 8.42 nM, 3.6 μg/kg for FIP and 9.72 nM, 4.04 μg/kg for FIP-S. This sensor was successfully used to detect FIP and FIP-S in eggs and water samples with good recoveries of 90%-106.6%.

Fusion expression of nanobodies specific for the insecticide fipronil on magnetosomes in Magnetospirillum gryphiswaldense MSR-1

BACKGROUND

Magnetic nanoparticles such as magnetosomes modified with antibodies allow a high probability of their interaction with targets of interest. Magnetosomes biomineralized by magnetotactic bacteria are in homogeneous nanoscale size and have crystallographic structure, and high thermal and colloidal stability. Camelidae derived nanobodies (Nbs) are small in size, thermal stable, highly water soluble, easy to produce, and fusible with magnetosomes. We aimed to functionalize Nb-magnetosomes for the analysis of the insecticide fipronil.

RESULTS

Three recombinant magnetotactic bacteria (CF, CF+ , and CFFF) biomineralizing magnetosomes with different abundance of Nbs displayed on the surface were constructed. Compared to magnetosomes from the wild type Magnetospirillum gryphiswaldense MSR-1, all of the Nb-magnetosomes biosynthesized by strains CF, CF+ , and CFFF showed a detectable level of binding capability to fipronil-horseradish peroxidase (H2-HRP), but none of them recognized free fipronil. The Nb-magnetosomes from CFFF were oxidized with H₂O₂ or a glutathione mixture consisting of reduced glutathione and oxidized glutathione in vitro and their binding affinity to H2-HRP was decreased, whereas that to free fipronil was enhanced. The magnetosomes treated with the glutathione mixture were employed to develop an enzyme-linked immunosorbent assay for the detection of fipronil in water samples, with average recoveries in a range of 78-101%.

CONCLUSIONS

The economical and environmental-friendly Nb-magnetosomes biomineralized by the bacterial strain MSR-1 can be potentially applied to nanobody-based immunoassays for the detection of fipronil or nanobody-based assays in general.