Disturbance of glutamate metabolism and inhibition of CaM-CaMKII-CREB signaling pathway in the hippocampus of mice induced by 1,2-dichloroethane exposure

1,2-Dichloroethane (1,2-DCE) is a highly toxic neurotoxicity, and the brain tissue is the main target organ. At present, long-term exposure to 1,2-DCE has been shown to cause cognitive dysfunction in some studies, but the mechanism is not clear. The results of this study showed that long-term 1,2-DCE exposure decreased learning and memory abilities in mice and impaired the structure and morphology of neurons in the hippocampal region. Moreover, except for the mRNA level of PAG, the enzymatic activities and protein levels of GS and PAG, as well as the mRNA level of GS were inhibited. With increasing dose of exposure, the protein and mRNA expression of GLAST and GLT-1 also decreased. Contrarily, there were protein and mRNA expression upregulation of GluN1, GluN2A and GluN2B in the hippocampus, as well as increased levels of extracellular Glu and intracellular Ca²⁺. In addition, 1,2-DCE exposure also downregulated the protein expression levels of CaM, CaMKII and CREB. Taken together, our results suggest that long-term 1,2-DCE exposure impairs the learning and memory capacity in mice, which may be attributed to the disruption of Glu metabolism and the inhibition of CaM- CaMKII-CREB signaling pathway in the hippocampus.

Neuropsychological effects of ethylene dichloride exposure

Production of 1,2-dichloroethane (EDC) has increased and exposure to it has been reported to produce adverse effects in animals and CNS effects in humans. A group of 221 EDC exposed hazardous clean-up workers incurred chronic exposure to EDC without protective equipment. A clinical history and the following tests were administered: the WHO Adult Environmental Neurobehavioral Test Battery (AENTB), Wechsler Adult Intelligence Scale (WAIS-III), Wechsler Memory Scale (WMS-III); WRAT 3 Reading, Cancellation H, Trail Making, Stroop, Rey Osterreith, Animal Naming, COWAT, TOMM, Rey 15, Lanthony d-15 Color Vision, and Vistech Contrast Sensitivity. Mood and symptoms were assessed with the SCL90-R, BDI, BAI and IES. The clinical neuropsychological evaluation of these workers indicates lower neuropsychological functioning in the domains of processing speed; attention; cognitive flexibility; motor coordination and speed; verbal memory; verbal fluency; and visuo-spatial abilities. These workers also showed disturbed mood and impaired vision. Dose/response relationships between exposure to EDC and test scores are shown.