title: 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.
authors.affiliation: University of Wisconsin-Stout, Menomonie, WI, USA.
authors.forename: C D
authors.initials: CD
authors.lastname: Seaborn
authors.forename: F H
authors.initials: FH
authors.lastname: Nielsen
mesh_terms: D000818:Animals; D003094:Collagen / Q000096:biosynthesis*; D004032:Diet; D005269:Femur / Q000293:injuries / Q000378:metabolism*; D006909:Hydroxyproline / Q000032:analysis; D020007:Implants, Experimental; D008099:Liver / Q000201:enzymology*; D008297:Male; D009953:Ornithine-Oxo-Acid Transaminase / Q000378:metabolism*; D011145:Polyvinyls / Q000737:chemistry; D011392:Proline / Q000008:administration & dosage; D051381:Rats; D017207:Rats, Sprague-Dawley; D012825:Silicon / Q000008:administration & dosage / Q000172:deficiency*; D014945:Wound Healing / Q000187:drug effects*
chemical_list: D011145:Polyvinyls; C026699:ivalon sponge; D003094:Collagen; D011392:Proline; D009953:Ornithine-Oxo-Acid Transaminase; D006909:Hydroxyproline; D012825:Silicon