|Stoecker, Barbara - OKLAHOMA ST UNIV|
Submitted to: Journal of Federation of American Societies for Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: December 1, 2003
Publication Date: March 24, 2004
Citation: Nielsen, F.H., Stoecker, B. 2004. Nutritional intakes of silicon affect vertebral trabecular microarchitecture and strength, but not femoral or vertebral strength changes induced by ovariectomy, in rats [abstract]. Federation of American Societies for Experimental Biology Journal. 18:A919. Technical Abstract: Supra nutritional amounts of silicon (Si) inhibit vertebral osteopenia induced by ovariectomy (ovx) in rats (Rico et al, Calcif. Tissue Int 66:53, 2000). Thus, we performed an experiment to determine whether Si deprivation exacerbates bone changes induced by ovx. Groups of 20 female weanling Sprague-Dawley rats were fed a diet containing ~2 mg Si/kg and supplemented with either 0 or 35 mg Si/kg. After 17 weeks, 10 rats in each group were ovariectomized; the other 10 received a sham-operation. Five weeks later, blood was collected under anesthesia before euthanasia for removal of femurs and vertebrae. Femur bending moment determined by a 3-point bending test was increased 10% by ovx, a change not altered by Si. The fourth lumbar vertebrae from 4 randomly selected rats in each group were examined by micro-computed tomography and then assessed for crushing strength. Trabecular thickness and vertebra stiffness (crushing strength indicator) were each independently decreased by Si deprivation and ovx. Ovx increased trabecular core height in Si-supplemented but not in Si-deprived rats (core height similar to ovx rats). Plasma osteopontin was increased by 25% by Si deprivation, but unaffected by ovx. Plasma alkaline phosphatase was increased 65% by ovx, but unaffected by Si deprivation. The findings show that Si deprivation affects trabecular bone strength and structure, and does not exacerbate bone changes induced by ovx.