Abstract： Objective To investigate the effects of electromagnetic pulses (EMP) on the apoptosis and transforming growth factor beta 3 (TGF-β3) expression of mouse testis tissue.Methods Thirty-two male BALB/ c mice were randomly and equally divided into one control group and three EMP treated groups,which were whole-body exposed to EMP at 200 kV/m with 100,200,and 400 pulses,respectively.The control group received no treatment.The pathological changes and cell apoptosis in testis tissue were analyzed by TUNEL assay.The mRNA expression of TGF-β3 in testis tissue was determined by RT-PCR,and the protein expression of TGF-β3 was determined by immunohistochemistry and Western blot.Results No obvious pathological changes were found in testis tissue after EMP exposure at 200 kV/m with 100 and 200 pulses.However,after EMP exposure with 400 pulses,degeneration and shedding of testis tissue,accompanied by significant increase in apoptosis rate (P＜0.05),was observed.The RT-PCR,immunohistochemistry,and Western blot showed that the expression of TGF-β3 mRNA and protein increased significantly after EMP exposure with 400 pulses as compared with that of the control group (P＜0.05).Conclusion EMP exposure at 200 kV/m with 400 pulses increases the incidence of apoptosis and expression of TGF-β3 in mouse testis tissue,which is potentially one of the mechanisms by which EMP increases blood-testis barrier permeability in mice.