Abstract: Objective To study the impact of lead exposure on the expressions of three main subtypes of neural cell adhesion molecule(NCAM).Methods NCAM 120,NCAM 140 and NCAM 180 recom binant plasmids were transfected in to SHSY 5Y cells separately using cationic lipo some transient transfection.After identification with mimuno histochemistry and Western blot,the cells were cocultivated with 1 mol/L or 10 mol/L PbC l2 for 24 or 48 hours.Then the expressions of three subtypes of NCAM were detected with We sternblot.Results After lead exposure for 24 or 48 hours,the expressions of NCAM 120 and NCAM 140 were reduced in the cells compared to that of the negative control group.The AO ratios of N CAM 120 decreased from 0.580(24h r)and 0.225(48hr)to 0.154 and 0.017;while the AO ratios of NCAM 180 decreased from 0.086(24hr)and 0.062(48hr)to 0.042 and 0.046.However,for the cells transfected with NCAM 140,only in the group with 10 mol/L lead exposure,the AO ratios decreased from 1.049(24hr)and 1.027(48hr)to 0.836 and 0.868.Conclusion Lead could influence the expression of the three subtypes of NCAM NCAM 120,NCAM 140 and NCAM 180,and the expresion of NCAM 120 is a ffected mostseriously by lead exposure.