| [Objective] Persistent exposure to inorganic lead (Pb) is known to adversely affect the immune system. This toxic metal damages the immune response of animals as well as humans. In the process of intestinal absorption, has Competitive inhibition between Pb and Ca. However, little is known about the effects and Competitive mechanisms of Pb and Ca on the immune system. The present study is undertaken to investigate the immunological effects of calcium supplement in lead-poisoning rats.[Methods] In the test,60 healthy (50±5g) male SD rats were randomly divided into five groups, and named as Normal Control group(Basic feed, deionized water), Pb model group(Basic feed,0.2% lead acetate), Test Ⅰ group (Basic feed add 0.5% calcium carbonate,0.2% lead acetate), Test Ⅱ group (Basic feed add 1%calcium carbonate,0.2% lead acetate), Test Ⅲ group (Basic feed add 2% calcium carbonate,0.2% lead acetate). After 60 days of administration,blood mineral element (Pb, Ca, Fe, Zn, Mn, Mg, Cu) content, WBC (white blood cell), IgG and organ index and splenic organ histopathological observations were performed. In addition, expression levels of transcription factors IL-1β, IL-6 and TNF-α were quantified by real-time RT-PCR.[Results] (1)compared with control group, heart, liver, spleen, kidney, muscle and blood lead levels increased significantly (P<0.05 or P<0.01); Calcium content of tissue were lower (P< 0.05); Fe of spleen, Cu of liver, Zn of blood content were lower, Mg of heart were higher, very significant difference (P<0.05 or P<0.01);Compared with dye the lead group, Pb of experimental group rats decreased, test Ⅱ group reduced obviously in the tissue (P<0.05 or P<0.01); calcium content of each tissue, test Ⅰ and Ⅱ reached significant difference (P<0.05); Cu and Zn content in each group was increased, in the heart, liver, kidney, muscle of test Ⅱ group significant difference (P<0.05). The right amount of calcium intervention can keep up bivalent mineral elements balance in animal tissue.(2) Compared with control group, in lead group rats, spleen index, white blood cells, lymphocytes percentage and IgG decreases (P<0.05 or P<0.01), the percentage of monocytes cells and neutrophilic cells rise (P<0.05 or P<0.01), the boundary is not obvious between the red and white pulp, some dissolved occur, arrange sparse lymphocytes, lymph nodule number is less. Compared with dye the lead group, the spleen index, white blood cell count of test Ⅱ group and IgG of test Ⅲ group rise (P<0.05); The percentage of monocytes cells and neutrophilic cells decreases, but no significant difference; Lymphocytes increased, the boundary is obvious between red and white pulp and lymphocyte basic returned to normal in spleen of test Ⅱ group rats, but lymph node have obvious dispersion phenomenon in test Ⅲ group. Visible, added a dose of calcium can relief to body’s immune injury, improve dye lead the body’s immune ability, in a certain extent.(3) Compared with the control group, the lymphoid tissue of spleen decreased, between the red and white pulp closed, melhado center formation, the white pulp and red pulp lymphocytes decreased significantly, some dissolved phenomenon, and lymphoid nodule formation rarely. But, the above phenomenon disappear after calcium supplement.(4) Compared with the control group, the expression of IL-1 β、IL-6、TNF-α in the spleen of model group significantly decreased (P<0.05 or P<0.01). Compared with the Model group, the expression of IL-1β、IL-6、TNF-α in the spleen of Dose Ⅱ groups increased (P<0.01).[Conclusion] Lead exposure male rats decreased blood Ca, Zn, Cu and Mn, WBC and the spleen and cardiac index content levels, increased blood Pb, LYMPH (lymphocytes percentage), MONO(monocyte) and the liver and kidney index levels. Calcium supplements with lead-poisoning groups, however, result to a decrease in the elevated blood Pb, LYMPH, MONO and the liver and kidney index levels, while blood Ca, Zn, Cu and Mn, WBC and the spleen and cardiac index content levels. In addition, calcium significantly increased the IL-1β, IL-6 and TNF-α expression in the spleen compared to Lead exposure model group.In brief, these study demonstrates that proper calcium has played an improtant role in protecting the lead-induced immune system damage of lead exposure model rats. |
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