Comparative Analysis Of The Effects Of Mercuric Chloride On Immune Cells Of Spleen And Abdominal Cavity In Different Strain Mice

Objective In this study,six strains of mice commonly used in immune-toxic were selected.To further understand the mechanisms of mercuric immunotoxicity,we compared the immunological parameters and mercury-mediated immune-toxic effects in these six-strain mice.Methods Female 8-week-old C57BL/6,DBA/2,SJL,FVB/N,BALB/c and KM mice were employed in this study.By using flow cytometry,we first determined the cell number of spleen and abdominal cavity,and the percentage of T cells(CD3+cells)and B cells(CD 19+cells),and the percentage of T cell subpopulations(CD4+T cells,CD8+T cells),and the percentage of Treg(CD25+FoxP3+cells)among CD4+T cells.The peritoneal cavity was flushed with PBS to obtain peritoneal lavage,and the percentage of T cells,B cells,Gr1+ cells,and CD11b+ cells were determined.Second,by using modified Kou’s method,we measured median lethal dose(LD50)of mercuric chloride via intraperitoneal injection of two stains mice,C57BL/6 and BALB/c mice.Third,six strains of mice were divided into control group and mercury chloride-treated group,respectively.The mercury group mice were injected intraperitoneally with mercuric chloride at a single dose of 5 mg/kg.The control group mice were received 0.9%saline in the same manner.The cell number and the percentage of immune cells in spleen abdominal cavity were measured as described above after 24 h.Results The immune cell numbers of spleen,in sequence,are SJL,FVB/N,KM>C57BL/6,DBA/2,BALB/c;abdominal cavity,are SJL,KM>C57BL/6,DBA/2,FVB/N,BALB/c.The percentage of T cells in the spleen are SJL>BALB/c,FVB/N>C57BL/6,KM>DBA/2,while percentages of B cells are opposite.The composition ratio of CD4+cells among T cells of DBA/2,SJL and FVB/N mice was higher than those of other three strains of mice.The percentage of Treg cells among CD4+cells,in turn,is SJL>DBA/2>C57BL/6,BALB/c,KM>FVB/N.In the abdominal cavity,the percentage of B cells is SJL>BALB/c,KM>DBA/2>C57BL/6,FVB/N;and the percentage of CDllb+cells is C57BL/6,DBA/2,FVB/N>BALB/c>SJL,KM.The results of LD50 showed that the dosage of BALB/c mice was 5.25 mg/kg and C57BL/6 mice was 8.89 mg/kg post intraperitoneal injection with mercuric chloride.Mercury significantly increased the cell number of peritoneal cavity in C57BL/6,SJL,FVB/N and BALB/c mice,compared those with the same-strain control group mice.Mercury did not affect the composition of T and B cells in six strain mice,but significantly increased the percentage of Treg cells among CD4+ cells in DBA/2,B ALB/c,FVB/N and KM mice.Mercury significantly decreased the percentages of B cells and CD11b+cells(except for SJL mice)in the peritoneal cavity in the six strains of mice.In another hand,mercury dramatically increased the percentages of Gr1+ cells,in turn,BALB/c>DBA/2,FVB/N>C57BL/6,SJL,KM.Conclusion C57BL/6,DBA/2,SJL,FVB/N,BALB/c and KM strains have different immune cell composition in the spleen and abdominal cavity.Mercury decreases the composition of B and CD11b+ cells in abdominal cavity,while recruits Grl+cells and its scale depends on mouse strain.