Silicon Deprivation Decreases Collagen Formation in Wounds and Bone, and Ornithine Transaminase Enzyme Activity in Liver

Abstract

We have shown that silicon (Si) deprivation decreases the collagen concentration in bone of 9-wk-old rats. Finding that Si deprivation also affects collagen at different stages in bone development, collagen-forming enzymes, or collagen deposition in other tissues would have implications that Si is important for both wound healing and bone formation. Therefore, 42 rats in experiment 1 and 24 rats in experiment 2 were fed a basal diet containing 2 or 2.6 microg Si/g, respectively, based on ground corn and casein, and supplemented with either 0 or 10 microg Si/g as sodium metasilicate. At 3 wk, the femur was removed from 18 of the 42 rats in experiment 1 for hydroxyproline analysis. A polyvinyl sponge was implanted beneath the skin of the upper back of each of the 24 remaining rats. Sixteen hours before termination and 2 wk after the sponge had been implanted, each rat was given an oral dose of 14C-proline (1.8 microCi/100 g body wt). The total amount of hydroxyproline was significantly lower in the tibia and sponges taken from Si-deficient animals than Si-supplemented rats. The disintegrations per minute of 14C-proline were significantly higher in sponge extracts from Si- deficient rats than Si-supplemented rats. Additional evidence of aberrations in proline metabolism with Si deprivation was that liver ornithine aminotransferase was significantly decreased in Si-deprived animals in experiment 2. Findings of an increased accumulation of 14C-proline and decreased total hydroxyproline in implanted sponges and decreased activity of a key enzyme in proline synthesis (liver ornithine aminotransferase) in Si-deprived animals indicates an aberration in the formation of collagen from proline in sites other than bone that is corrected by Si. This suggests that Si is a nutrient of concern in wound healing as well as bone formation.

Dietary silicon affects bone turnover differently in ovariectomized and sham‐operated growing rats

“…Evidence that that silicon exerts its effect through altering the action of an extracellular matrix protein such as the cytokine osteopontin was not obtained. Nonetheless, the findings show that silicon influences the presence of cytokines in tissues and fluids other than bone, which could be the basis for silicon being beneficial to immune function [11] and wound healing [12].…”

“…Osteopontin is a phosphorylated acidic glycoprotein that apparently is important in bone remodeling, wound healing, and certain types of cell-mediated immune responses [8,9]. Recent reports confirm that silicon is involved in bone formation [10], silicon deficiency impairs splenic lymphocyte proliferation in response to an immune challenge [11], and silicon may be important for wound healing [12]. Thus, the following experiment was designed to test the hypothesis that silicon deficiency affects the production or function of osteopontin such that circulating amounts would be modified and this would be associated with changes in indicators of bone turnover, strength, and physical characteristics.…”

“…Because of reports that osteopontin synthesis is increased in bone cells of ovariectomized animals [13], the effect of ovariectomy on the possible relationship between silicon and circulating osteopontin also was examined. Furthermore, because both ovariectomy [14] and silicon deprivation [4] of growing rats alters organic matrix characteristics, and both affect ornithine aminotransferase activity [12,15], which is involved in collagen formation, it was hypothesized that ovariectomy would alter changes in bone turnover indices induced by silicon deprivation.…”

The pathway to intelligent implants: osteoblast response to nano silicon-doped hydroxyapatite patterning

“…SiHA has a greater rate of in vivo dissolution, in comparison with that of HA [6] as well as a greater rate of bone apposition [3]. The primary effect of Si in bone and cartilage is thought to be associated with matrix synthesis, although its influence on calcification may be an indirect phenomenon from matrix components [7]. Silicon has been found to promote collagen type 1 synthesis, which constitutes 90 per cent of extracellular matrix (ECM), enhance osteoblast differentiation [8] and prevent poor host bone metabolism in defect repair [2].…”

Silicon bioavailability in exocarp of Cucumis sativus Linn.

“…In addition, silicon has also been reported to play a significant physical, biochemical, and molecular role in plants, human, and animals, and considered as nutritionally important element (Epstein 1999;Tripathi et al 2012a, b;Vasanthi et al 2012;Seaborn and Nielsen 1993); whereas in humans, the role of silicon is more important as it is essential for maintaining skeletal health (Seaborn and Nielsen 1993). In general, animal and human beings ingest silicon through the food, vegetable, and feed materials and its most of the amount excreted by the faeces and urine, and thus, only a tiny amount is engrossed which plays a critical role in the body (Vasanthi et al 2012).…”