Silicon as an essential element
Carlisle, E.M.
Federation Proceedings 33(6): 1758-1766
1974
ISSN/ISBN: 0014-9446 PMID: 4275098 Document Number: 82758
Studies on the bones of young rats and mice showed sites rich in Si in the osteoid tissue at the edge of trabeculae. Si and Ca rose congruently during bone mineralisation but in more advanced stages Si fell and as Ca approached the proportions present in bone apatite Si was present at the detection limit only. In weanling rats, nursed by mothers on a diet low in Si, which were given diets with Si 10, 25 and 250 mg/kg each of which had Ca 0.08, 0.4 and 1.2%, Si accelerated mineralisation of the tibia. Experiments on chickens showed a relation between Si, Mg and F in growing bone. Chickens which were given a diet deficient in Si for 23 days gained 49.8% less weight than chickens given a supplement of Si. Those deprived of Si had abnormalities of the articular cartilage and connective tissue; their long bone joints were smaller and the bones contained 34 to 35% less water than those of the controls. The control chickens given the supplement had larger amounts of articular cartilage and larger combs with a greater content of Si and greater proportions of hexosamines in those tissues than the deprived chickens. From those and other studies it is concluded that Si is not merely involved in mucopolysaccharide synthesis but is an essential component. Si in the aorta, skin and thymus in several species fell significantly with age, in contrast to that in other tissues which showed little or no change; this effect is probably related to mucopolysaccharide changes. Acting as a cross-linking agent Si may contribute to the structural integrity of connective tissue.