Preliminary studies on the mode of activity of CdCl2 in combination with nicotine in spermatogonial cells
Objective To investigate the combined effect of CdCl2 and nicotine on the cell cycle and apoptosis of mouse spermatogonium(GC-1).Methods A CCK-8 assay was used to detect the inhibition of GC-1 cell proliferation in the CdCl2 groups,nicotine groups,and combined groups at 24 hours.Flow cytometry was used to detect the effects of CdCl2,nicotine,and the combined treatment on the cell cycle and apoptosis of GC-1 cells at 24 hours.Results The inhibitory effect on the proliferation of GC-1 cells increased with the rise in CdCl2 and nicotine concentrations.The IC50 values of CdCl2 and nicotine alone were 5.409 μmol/L and 2814 μmol/L,respectively.The IC50 values of CdCl2 and nicotine combined for GC-1 cells were 4.422,4.532,3.309,and 2.532 μmol/L at nicotine concentrations of 0.175,0.350,0.700,and 1.400 mmol/L,respectively,thus there was an obvious decrease with nicotine concentration.The IC50 values were lower than those of the group administered CdCl2 alone,and the combined action of CdCl2 and nicotine had synergistic effects.Cell cycle result showed that CdCl2 concentration of 2.5 μmol/L increased the percentage of G2/M phase cells in the combination groups.Cells were arrested in the G2/M phase in the combined groups(P<0.01).When combined,CdCl2 and nicotine had a synergistic effect on the cell cycle,and the synergistic effect of CdCl2 was stronger.The result of apoptosis showed the proportion of cells in apoptosis increased in the 2.5 μmol/L CdCl2 group.Compared with the CdCl2 and nicotine single-treatment groups,the CdCl2 and nicotine combined group's percentage of cells in apoptosis increased significantly(P<0.01),and CdCl2 had a stronger synergistic effect.Conclusions Combinations of CdCl2 and nicotine had a synergistic effect on mouse spermatogonium(GC-1)and led to enhanced cytotoxicity,G2/M cell cycle arrest,and cell apoptosis.CdCl2 was the main effect factor in the synergistic effect.