The decrease in silicon concentration of the connective tissues with age in rats is a marker of connective tissue turnover

Abstract

Silicon may be important for bone and connective tissue health. Higher concentrations of silicon are suggested to be associated with bone and the connective tissues, compared with the non-connective soft tissues. Moreover, in connective tissues it has been suggested that silicon levels may decrease with age based upon analyses of human aorta. These claims, however, have not been tested under controlled conditions. Here connective and non-connective tissues were collected and analysed for silicon levels from female Sprague–Dawley rats of different ages (namely, 3, 5, 8, 12, 26 and 43 weeks; n = 8–10 per age group), all maintained on the same feed source and drinking water, and kept in the same environment from weaning to adulthood. Tissues (696 samples) were digested in nitric acid and analysed by inductively coupled plasma optical emission spectrometry for total silicon content. Fasting serum samples were also collected, diluted and analysed for silicon. Higher concentrations of silicon (up to 50-fold) were found associated with bone and the connective tissues compared with the non-connective tissues. Although total silicon content increased with age in all tissues, the highest connective tissue silicon concentrations (up to 9.98 μg/g wet weight) were found in young weanling rats, decreasing thereafter with age (by 2–6 fold). Fasting serum silicon concentrations reflected the pattern of connective tissue silicon concentrations and, both measures, when compared to collagen data from a prior experiment in Sprague–Dawley rats, mirrored type I collagen turnover with age. Our findings confirm the link between silicon and connective tissues and would imply that young growing rats have proportionally higher requirements for dietary silicon than mature adults, for bone and connective tissue development, although this was not formally investigated here. However, estimation of total body silicon content suggested that actual Si requirements may be substantially lower than previously estimated which could explain why absolute silicon deficiency is difficult to achieve but, when it is achieved in young growing animals, it results in stunted growth and abnormal development of bone and other connective tissues.

Biomimetic Nanosilica–Collagen Scaffolds for In Situ Bone Regeneration: Toward a Cell‐Free, One‐Step Surgery

“…In contrast, disorganized fibrous tissue infiltrated the DCB scaffold (stained red). These results are also supported by the literature in regard to the active involvement of Si ions in matrix synthesis, maturation, and turnover to maintain matrix stabilization . Therefore, these nSC composites indeed provide a natural bone ECM‐mimicking niche for endogenous cells to attach, grow, and differentiate into mature bone tissue and thus present a superior capacity for enhanced bone regeneration.…”

A 12-week randomized, double-blind, placebo-controlled multicenter study of choline-stabilized orthosilicic acid in patients with symptomatic knee osteoarthritis

“…Indeed, Zhang et al recently reported elevated serum homocysteine levels in patients with severe OA compared to those with mild OA or healthy controls [29]. Secondly, although the exact role of silicon in bone and connective tissue health remains unclear, its involvement in collagen synthesis and/or stabilisation was recently put forward by Jugdaohsingh et al [30]. In the present study, the lack of correlation between the change in serum silicon and clinical parameters in men taking ch-OSA, suggests that the effect of ch-OSA cannot be explained as an effect of silicon only.…”

Correlations among plasma silicon, magnesium and calcium in patients with knee osteoarthritis – analysis in consideration of gender

“…Silicon is a microelement whose role and essentiality for the human organism remains unclear [25]. However, in view of the available research data its connection with the functioning of connective tissues seems to be unquestionable [26,27]. An association has been found between dietary silicon and bone condition in humans [28].…”