Pesticide Exposure and Its Association with Parkinson's Disease: A Case-Control Analysis

Abstract

Parkinson's disease (PD) is a complex disorder that arises from genetic and environmental factors. The current investigation endeavors to investigate the role of exposure to organochlorine (OCPs) and organophosphate pesticides (OPPs), recognized as the main environmental elements, in the genesis of PD. In this case-control study, 29 PD patients and 51 healthy subjects were involved. Gas chromatography was performed to measure the serum levels of organochlorine chemicals (2,4-DDT, 4,4-DDT, 2,4-DDE, 4,4-DDE, α-HCH, β-HCH, and γ-HCH). Furthermore, acetylcholinesterase (AChE) activity, arylesterase activity of paraoxonase-1 (PON-1), and several oxidative stress (OS) markers were assessed. The levels of OCPs in the PD patients were significantly higher than in the control subjects. In addition, AChE activity, arylesterase activity of PON-1, catalase activity, and superoxide dismutase 3 activity in PD patients were significantly less than controls. However, the levels of carbonyl protein, total antioxidant capacity, malondialdehyde, and nitric oxide in PD patients were higher than the controls. The findings of this investigation have indicated that OCPs and OPPs exposure could contribute to the development of Parkinson's disease. This potential linkage could either be established through the direct impact of these pesticides on the nervous system, leading to neurotoxicity, or via an indirect route through the triggering of OS.

Keywords: Organochlorine pesticides; Organophosphate pesticides; Oxidative stress; Parkinson’s disease; Pesticide exposure.

Fig. 1

The serum levels of OCPs were measured by the GC. The figure demonstrates an example chromatograph of controls (A) and patients (B) to reveal the appropriate performance of the used GC method, as well as a presentation of higher levels of OCPs in patients with PD. a-HCH α-Hexachlorocyclohexane, b-HCH β-Hexachlorocyclohexane, 2,4-DDE 2,4-Dichlorodiphenyldichloroethylene, 4,4-DDE 4,4-Dichlorodiphenyldichloroethylene, 2,4-DDT 2,4-Dichlorodiphenyltrichloroethane, 4,4-DDT 4,4-dichlorodiphenyltrichloroethane

Fig. 2

The serum levels of the studied OCPs in patients with PD compared to controls. The scatter chart compares the serum levels of OCPs in patients to the control group (C). As the figure represents, all seven OCPs were significantly higher in the patients compared to the control group. OCPs organochlorine pesticides, alpha-HCH α-Hexachlorocyclohexane, beta-HCH β-Hexachlorocyclohexane, gamma-HCH γ-Hexachlorocyclohexane, 2,4-DDE 2,4-Dichlorodiphenyldichloroethylene, 4,4-DDE 4,4-Dichlorodiphenyldichloroethylene, 2,4-DDT 2,4-Dichlorodiphenyltrichloroethane, 4,4-DDT 4,4-Dichlorodiphenyltrichloroethane

Fig. 3

The comparison of biochemical factors between patients with PD and controls. The charts compare some oxidative stress factors between patients and controls. The activity of AChE, PON-1, CAT, and SOD3 enzymes in patients was significantly lower than in controls, whereas the levels of MDA, TAC, CP, and NO in patients were remarkably higher when compared to controls. There was no difference between the two groups regarding GPx3 activity. AChE acetylcholinesterase, MDA malondialdehyde, TAC total antioxidant capacity, PON-1 paraoxonase-1, CAT catalase, SOD superoxide dismutase, GPx glutathione peroxidase, CP carbonyl protein, NO nitric oxide