Characterization of plasma cholinesterase in rabbit and evaluation of the inhibitory potential of diazinon

The protective effects of erdosteine on subacute diazinon-induced oxidative stress and inflammation in rats

In today's world, pesticides are commonly used to control pests and in advanced agriculture. As an organophosphorus insecticide (OPI), diazinon (DZN) is a commonly used substance. However, the widespread usage of DZN increases the probability of incidence of toxication. This toxication has been reported to be shaped not through cholinergic syndromes that are experienced as a result of acetylcholinesterase inhibition, which is the primary effect of these cases. It is rather shaped by the altering of the facilitation of oxidative stress and inflammatory response. In this study, the protective effect of administering erdosteine (ERDOS) subacute DZN exposure was investigated. A total of 24 male Wistar albino rats were separated into 4 groups (with 6 rats in each group), namely, the control, DZN (15 mg/kg/day), ERDOS (10 mg/kg/day), and DZN + ERDOS (15 mg/kg/day DZN + 10 mg/kg/day ERDOS) groups. These medications were given through oral gavage for 28 days. With the whole blood, plasma, and serum samples taken from the rats, oxidant-antioxidant parameters and cytokine levels were measured. The MDA and NOx levels and SOD and CAT enzyme activities of the DZN group were higher than those of the control group, while the GSH levels and TAC and GPx activities of the DZN group were lower than those of the control group (p < 0.05). It was also found that cytokine (IL-1β, IL-10, and TNF-α) levels in the DZN group were higher than those in the control group (p < 0.05). On the other hand, the ERDOS implementations were detected to ameliorate the harmful effects of DZN on the oxidant-antioxidant parameters and cytokine levels (p < 0.05). Conclusively, besides the known mucolytic efficacy of ERDOS, it may also be stated to display free radical scavenger, antioxidant, and anti-inflammatory characteristics to inhibit some proinflammatory cytokines that are specifically involved in oxidative stress. Additionally, the ameliorating property of ERDOS can be benefited from in possible DZN-induced toxication cases.

Metabolism-Coupled Cell-Independent Acetylcholinesterase Activity Assay for Evaluation of the Effects of Chlorination on Diazinon Toxicity

Drinking water quality guideline values for toxic compounds are determined based on their acceptable daily intake. The toxicological end point for determining the acceptable daily intake of most organophosphorus insecticides is inhibition of acetylcholinesterase (AChE). Although insecticides ingested with drinking water are partly metabolized by the liver before transport to the rest of the body, no current cell-independent AChE activity assay takes the effects of metabolism into account. Here, we incorporated metabolism into a cell-independent AChE activity assay and then evaluated the change in anti-AChE activity during chlorination of a solution containing the organophosphorus insecticide diazinon. The anti-AChE activities of solutions of diazinon or diazinon-oxon, the major transformation product of diazinon during chlorination, were dramatically changed by metabolism: the activity of diazinon solution was markedly increased, whereas that of diazinon-oxon solution was slightly decreased, clearly indicating the importance of incorporating metabolism into assays examining toxicity after oral ingestion. Upon chlorination, diazinon was completely transformed, in part to diazinon-oxon. Although diazinon solution without metabolism did not show anti-AChE activity before chlorination, it did after chlorination. In contrast, with metabolism, diazinon solution did show anti-AChE activity before chlorination, but chlorination gradually decreased this activity over time. The observed anti-AChE activities were attributable solely to diazinon and diazinon-oxon having been contained in the samples before metabolism, clearly suggesting that the presence not only of diazinon but also of diazinon-oxon should be monitored in drinking water. Further examination using a combination of tandem mass spectrometry and in silico site-of-metabolism analyses revealed the structure of a single metabolite that was responsible for the observed anti-AChE activity after metabolism. However, because this compound is produced via metabolism in the human body after oral ingestion of diazinon, its presence in drinking water need not be monitored and regulated.

Photocatalytic Degradation of Diazinon in Aqueous Solutions Using Immobilized MgO Nanoparticles on Concrete

Photocatalytic degradation of diazinon in the aqueous solution using UV light and MgO nanoparticle (NPs) immobilized on the concrete was investigated. Prepared catalyst was characterized using TEM, XRD, SEM, and EDX techniques. The results showed that the average particle size of immobilized MgO NPs was 38.3 nm and NPs appropriately was coated on the concrete surface. The performance of degradation and mineralization of diazinon was evaluated by HPLC and TOC techniques, respectively. The effect of operational parameters including pH value, initial pesticide concentration, and contact time were studied on the removal and mineralization of diazinon by a photocatalytic process. The results showed that the MgO NPs and UV light had little effect in removing pesticide when used individually. On the other hand, diazinon can be effectively degraded by immobilized MgO NPs in the presence of UV light. Degradation products of diazinon using the proposed photocatalytic technique were identified by the GC-MS analysis. The maximum diazinon removal (99.46 %) was obtained under the conditions; pH 7, diazinon concentration of 5 mg/L, and contact time of 120 minutes. Also, the lowest energy consumption conditions were as follow; pH 7, diazinon concentration of 5 mg/L, and contact time of 30 minutes.

Influence of sex on biomarkers of oxidative stress in the kidney, lungs, and liver of rabbits after exposure to diazinon

The present study evaluated the effect of two oral doses of the pesticide diazinon (25 and 125 mg/kg bw) on four biochemical parameters (malondialdehyde and glutathione levels, and catalase and glutathione S-transferase enzymatic activities) in the kidney, lungs, and liver of rabbit after 10 days of exposure. Malondialdehyde levels were significantly greater in exposed animals compared to controls, especially in the animals exposed to the higher dose of the pesticide. This result was reflected in the glutathione levels, which were significantly lower at that same higher dose. Catalase activity was also inhibited by the higher dose of the pesticide in all three organs analysed, whereas inhibition of glutathione S-transferase activity was only significant for the kidney and lungs. There were some slight differences between the sexes: taking the results for all three organs, the higher dose of diazinon resulted in a clearly significant inhibitory effect on the catalase activity and glutathione levels in males, and a significant enhancing effect on the malondialdehyde levels in females. These results help to confirm the interest of considering such endogenous factors in future ecotoxicological studies, and that the four biomarkers considered are suitable for reflecting the toxic effects of diazinon on rabbits, especially the effects related to oxidative stress. Graphical abstract.