The Immunotoxicity Of Lead,Cadmium And Mercury In Mice

ObjectiveLead,cadmium and mercury are the most common environmental pollutants in China,affecting many tissues and systems such as liver,kidney,nerve,skeleton,immunity and so on,which seriously harm the heASTh of people.In this study,we investigated the effects of lead,cadmium and mercury on the immune system,and the effects of these three heavy metals on the apoptosis rate of spleen cells and the ratio of immune cell composition.MethodFemale 8-week old BALB/c mice were randomly divided into 4 groups according to their weight,that is,the control group,the lead treated group,the cadmium treated group and the mercury treated group.Metal treated mice were oral exposed lead chloride and cadmium chloride and mercuric chloride,respectively.For three kinds of metals,we employed same dose as 18 ?M/kg,gavaged the mice three times a week for four weeks.The control mice received distilled water in the same way.After fourth weeks of treatment,the kidney,spleen and thymus were removed,and the weight was measured.The spleen cells were stained with fluorescent-conjugated monoclonal antibody or propidium iodide(PI),and measured by flow cytometeter.ResultsThe body weight and general heASTh of the mice were not affected by the three heavy metals during the 1-4 week after exposure.The weight of the kidney,spleen and thymus and the number of spleen cells were not affected in the fourth week after exposure.Compared with the control group,lead,cadmium and mercury significantly increased the apoptosis(Annexin-V+PI+)rate of spleen cells.Mercury significantly increased the percentage of CD19+B cells in spleen cells(P<0.05).In addition,cadmium and mercury significantly increased the percentage of CD25 and Foxp3 double positive cells among CD4+T cells.ConclusionThree kinds of heavy metals that Lead,Cadmium and Mercury can increase the apoptosis rate of spleen cells,and modulated the compositions of spleen cells.These results provide a new basis for further understanding the different toxicic effects of lead,cadmium and mercury on the immune system.