Abstract: Objective To study the effects of mitogen activated prote in kinase(MAPK)inhibitor PD 98059 on mRNA expression of Bcl-2 and Caspases-3 in NRK cells treated with cadmium chloride(CdCl₂).Methods Cell apoptosis was tested in NRK cells treated with CdCl₂ for 6 hr with flow cytometer.Nature kill(NRK)cells were pretreated with MAPK in hibitor PD 98059 for 1hr,then treated with various doses of CdCl₂.Realtime flourescent quantitative PCR was applied to monitor the mRNA expression of Bcl-2 and Caspase-3 in NRK cells after the treatment.Results CdCl₂ induced dose dependent apoptosis in NRK cells,and a decrease in Bcl-2 mRNA expression a swell as an increases in Capsase 3 mRNA expression.Pretreatment of NRK cells with MAPK inhibitor PD 98059 blocked effects of cadntium on Bcl-2 mRNA expression deerease and Caspase 3 mRNA expression increase.Conclusion MAPK inhibitor PD 98059 could interfere with the effects of CdCl₂ on Bcl-2 and Caspase 3m RNA expression in NRK cells.The results indicated MAPK signal pathway might be in volved in cadmuiminduced apoptosis.