The effect of organophosphate insecticide poisoning on the brain cells and neurotransmitters in humans

Abstract

Organophosphate compounds have been used as pesticides and as chemical warfare nerveagents. The mechanism of toxicity of OPs is the inhibition ofacetylcholinesterase, which results in accumulation of acetylcholine and the continued stimulationof acetylcholine receptors. Therefore, they are also called anticholinesterase agents.As most OPs are lipophilic, they penetratethe blood brain barrier, resulting in severe braindamage. Central nervous system effects include nonspecificsymptoms as irritability, restlessness, disorientation and confusion. The objective of this study was to prospectively evaluateearly levels of S100B, NSE, and MBP to assess their usefulness as diagnostic and prognostic tools for treatment and predicting the severity of OPP patients. This may limit or prevent secondary neuronal damage at the early stage of OPP and attenuate the subsequent neuropsychiatric and neurological impairments, thus reducing the long-term disability caused by exposure to OPs. Also the correlation between serum levels of S100B, NSE, and MBP with other biochemical parameters such as acetylcholine (as a neurotransmitter), pseudo cholinesterase, LDH, CPK, AST, ALT, urea, creatinine, sodium and potassium were studied. This study was conducted on 40 adult patients of both sexesadmitted with acute OPP to the PCC-ASUH. In addition to 20 chronically exposed subjects and 30 healthy volunteers serving as control. Those were classified into: Group (I): Control group: consisted of 15 males and 15 females (normal healthy volunteers who were not exposed to organophosphate compounds). Group (II): Chronic OPs exposure group: This group consisted of 15 males and 5 females, who were selected from farmworkers chronically exposed to OPs during their work in the fields and did not show any cholinergic symptoms. Group (III): Acute OPP patients group subdivided into: Group (IIIa): Acute moderate OPP patients group: This group consisted of 3 males and 17 females, who were admitted with mild, transient and spontaneously resolving symptoms (lacrimation, salivation, miosis and fasciculation). Group (IIIb):Acute severe OPP patients group: This group consisted of 7 males and 13 females who were admitted with severe or life threatening symptoms (Incontinence, apneic spells, Acute respiratory distress syndrome, diminished reflexes, seizures and coma). Blood samples were collected from all subjects for determination of the different parameters. The study revealed that there were high significant differences between the markers of nerve cells degeneration (S100B, NSE, MBP, ACh and PChE) in all patient groups when compared with the control group.The markers of tissue destruction (LDH and CPK) were also significantly increased in all patient groups when compared with the control group.Liver enzymes (AST and ALT) showedstatically significantincrease inacute patient groups, while no significant difference was reported in chronic exposure group (II).Kidney function markers (urea and creatinine) did not show valuable significant difference in all patient groups when compared with control group.In addition, serum Na+ level revealed no significant difference in all patient groups. On the other hand, serum K+ showed highly significant decreases in all patient groups.