Abstract: ObjectiveTo study the effect of lead and selenium on the survival,neurite length and the expression of neural cell adhesion molecule(NCAM)in primarily cultured hippocampal neurons.MethodsWistar pups at postnatal 24 hours were anesthetized with 75% ethanol and the neurons were separated.The hippocampal neurons were primarily cultured.After co-incubation with lead chloride and selenomethionine(SeMet),hippocampal neural cells survival was tested by methyl thiazolyl tetrazoliun(MTT)assay.The mean neurite length was determined by tracing the major neurite of each neuron using the softw are packages Image pro-plus.Western blot was employed to determine the expression of neural cell adhesion molecule.ResultsAfter two days'co-incubation with lead chloride and SeMet simultaneously,the average length of neurite outgrow th was 6-17μm longer than that of lead chloride group(P<0.05).Treatment with SeMet at 0.125,0.25,0.5,1.0,and 2.0μmol/L,SeMet combination with lead chloride induced an increase in the expression of neural cell adhesion molecule compared to that of with lead incubation alone,especially with lead and 1.0μmol/L SeMet group.The expression of neural cell adhesion molecule was 2.00 for secondary high-dose group,1.96 for moderate-dose group,1.89 for low-dose group,1.80 for secondary low-dose group,and 1.75 for high-dose group,respectively.The expression of NCAM140 was higher than the expression of NCAM180 in different treatment groups.ConclusionSelenium increases neurite outgrowth and the expression of neural cell adhesion molecule.