In vivo requirement for silicon in articular cartilage and connective tissue formation in the chick

Studies were undertaken to determine further effects of silicon deficiency in the chick. The diet and experimental conditions were the same as those used in previous studies to demonstrate the essentiality of silicon for growth and development. Skeletal and other abnormalities involving glycosaminoglycans in formation of articular cartilage and comb connective tissue were found to be associated with silicon deficiency. The bones of 1 day-old deutectomized cockerels fed a silicon supplemented diet and killed at 4 weeks of age had significantly greater amounts of articular cartilage and water as compared with the silicon deficient group and also a greater proportion of hexosamine in the cartilage. The greater water content in bones of the silicon supplemented chicks coincided with a larger content of glycosaminoglycans in the articular cartilage. A similar relationship was obtained in cockerel comb. In addition to larger amounts of connective tissue and of total hexosamine in combs of the supplemented group, a higher percentage of hexosamine and a higher silicon content was found. These findings provide the first evidence for a requirement for silicon in articular cartilage and connective tissue formation and that the site of action of silicon is in the glycosaminoglycan-protein complexes of the ground substance.