[Effects of Chlorpyrifos on Dopaminergic Neuronal Viability with Activation of Microglia]

Excessive microglial activation and subsequent neuroinflammation lead to neuronal cell death,which are involved in the pathogenesis and progression of several neurodegenerative diseases such as Parkinson’s disease.The objective of this study was to determine the involvement of chlorpyrifos(CPF)in the activation of microglia and production of inflammatory factors in response to CPF stimulation and the influence on the viability of dopaminergic(DA)neurons.We detected the change of BV-2cells morphology and expression of inducible nitric oxide(iNOS),cyclooxygenase-2(COX-2)mRNA and protein level upon CPF stimulation(0,1,3,6,12,24h)in BV-2(mouse brain microglia)cells by reverse transcription polymerase chain reaction(RT-PCR)or Western blot.We randomly assigned BV-2cells into CPF,menstruum dimethysulfoxide(DMSO)and normal saline(NS)groups.We stimulated The BV-2cells in the CPF group with CPF,and we stimulated the two control groups with DMSO or NS for 12 hours,respectively.We then collected the used culture media from the culture dishes and centrifuged it to remove the detached cells.Then,we used the supernatants as microglial conditioned media.We treated SH-SY5 Yneurons with various groups of microglial conditioned media for 24 hours.We observed the effect of conditioned media collected from BV-2cell on the viability of dopaminergic cell lines SH-SY5 Yusing MTT assay.We found that inflammatory factors iNOS,COX-2mRNA and protein levels were up-regulated upon CPF stimulation.Conditioned media from BV-2upon CPF stimulation is toxic to SH-SY5 Y.It might be concluded that the exposure to CPF may induce dopaminergic neuronal damage by the activation of inflammatory response,and a mechanism may be involved in Parkinson’s disease pathogenesis.