|Seaborn, Carol - U OF WISC - MENOMONIE|
|Briske-Anderson, Mary - U OF NORTH DAKOTA|
Submitted to: Biological Trace Element Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 20, 2001
Publication Date: June 1, 2002
Citation: Seaborn, C.D., Briske-Anderson, M., Nielsen, F.H. 2002. An interaction between dietary silicon and arginine affects immune function indicated by Con-A induced DNA synthesis of rat splenic T-lymphocytes. Biological Trace Element Research. 87(1-3):133-142. Interpretive Summary: There is evidence that both silicon and arginine can affect the ability to resist disease; that is, enhance immune function. However, there has been no examination of whether immune function responses are affected by an interaction between these two nutrients. Therefore, an experiment was conducted with rats with the objective of determining whether a high or supranutrional intake compared to a normal intake of arginine would affect immune function as measured by T-lymphocyte proliferation (increase) in the presence of adequate or inadequate dietary silicon. Lymphocytes are cells that fight infection in the body and can be stimulated to increase in number by the presence of a foreign substance in the body. In the test tube, this increase can be induced by a substance called concanavalin A (Con-A). After consuming the diets containing the variable arginine and silicon for nine weeks, spleen lymphocytes were isolated and stimulated with Con-A. Supplemental arginine significantly decreased the proliferation of the lymphocytes, but the response to arginine was influenced by dietary silicon; the response was more marked when the rats were fed adequate than when fed inadequate silicon. Also, when dietary arginine was normal, lymphocyte proliferation was higher in rats fed adequate than inadequate silicon. The findings show that an interaction between silicon and arginine can affect immune function and that assuring an adequate intake of silicon in the presence of a normal (not excessive) intake of arginine is helpful for maintaining good immune function.
Technical Abstract: Sporadic reports have appeared that suggest silicon plays a functional role in immune function by affecting lymphocyte proliferation. In addition, there is also considerable interest in supplemental arginine as a modulator of immune function. Therefore, the purpose of this animal experiment was to determine the effect of supplemental compared to adequate arginine on immune function as measured by splenic T-lymphocyte proliferation in the presence of adequate or inadequate dietary silicon. The independent variables were, per g fresh diet, silicon supplements 0 or 35 g and arginine supplements of 0 or 5 mg. The basal diet contained 7.82 mg L- arginine/g. After feeding the male rats (nine per treatment group) for eight weeks, spleen lymphoid cells were isolated and cultured with methyl- 3H thymidine. Supplemental arginine significantly decreased Con-A-induced DNA synthesis of splenic T-lymphocytes, but the response to arginine was influenced by dietary silicon. The decreased DNA synthesis was more marke when rats were fed adequate silicon than when fed inadequate silicon. Also, when arginine was not supplemented, DNA synthesis was higher in lymphocytes from rats fed an adequate silicon diet than rats fed the inadequate silicon diet. These findings support the hypothesis that an interaction between silicon and arginine affects immune function and that inadequate dietary silicon impairs splenic lymphocyte proliferation in response to an immune challenge.