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Silicon and boron differ in their localization and loading in bone.

Jugdaohsingh R, Pedro LD, Watson A, Powell JJ - Bone Rep (2014)

Bottom Line: Silicon and boron share many similarities, both chemically and biochemically, including having similar effects on bone, although their mechanisms of action are not known.Here we compared the loading of silicon and boron into bone, their localization and how they are influenced by age (growth & development), to obtain further clues as to the biological effects of these elements and, especially, to see if they behave the same or not.Highest silicon and lowest boron concentrations were found in the under-mineralized bone of younger rats and lowest silicon and highest boron concentrations were found in the fully mineralized bone of the adult rat.

View Article: PubMed Central - PubMed

Affiliation: MRC Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, United Kingdom.

ABSTRACT

Silicon and boron share many similarities, both chemically and biochemically, including having similar effects on bone, although their mechanisms of action are not known. Here we compared the loading of silicon and boron into bone, their localization and how they are influenced by age (growth & development), to obtain further clues as to the biological effects of these elements and, especially, to see if they behave the same or not. Bone samples were obtained from two different studies where female Sprague Dawley rats had been maintained on a normal maintenance diet for up to 43 weeks. Total bone elemental levels were determined by ICP-OES following microwave assisted acid digestion. Silicon and boron levels in the decalcified bones (i.e. the collagen fraction) were also investigated. Silicon and boron showed marked differences in loading and in their localization in bone. Highest silicon and lowest boron concentrations were found in the under-mineralized bone of younger rats and lowest silicon and highest boron concentrations were found in the fully mineralized bone of the adult rat. Overall, however total bone silicon content increased with age, as did boron content, the latter mirroring the increase in calcium (mineral) content of bone. However, whereas silicon showed equal distribution in the collagen and mineral fractions of bone, boron was exclusively localized in the mineral fraction. These findings confirm the reported association between silicon and collagen, especially at the early stages of bone mineralization, and show that boron is associated with the bone mineral but not connective tissues. These data suggest that silicon and boron have different biological roles and that one is unlikely, therefore, to substitute for the other, or at least boron would not substitute for Si in the connective tissues. Finally, we noted that silicon levels in the mineral fraction varied greatly between the two studies, suggesting that one or more nutritional factor(s) may influence the loading of Si into the mineral fraction of bone. This and the nature of the interaction between Si and collagen deserve further attention.

No MeSH data available.


Related in: MedlinePlus

Study 2: (a) Collagen concentration (mg/g wet weight; open circles) and (b) collagen content (mg; closed circles) of the decalcified tibia bones from female Sprague Dawley rats of different ages (weanling to adults). (b) The molar ratio of collagen:Si in the decalcified bone is shown (closed triangles). Data are means ± SE of n = 3–5 rat bones per age group.
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f0020: Study 2: (a) Collagen concentration (mg/g wet weight; open circles) and (b) collagen content (mg; closed circles) of the decalcified tibia bones from female Sprague Dawley rats of different ages (weanling to adults). (b) The molar ratio of collagen:Si in the decalcified bone is shown (closed triangles). Data are means ± SE of n = 3–5 rat bones per age group.

Mentions: As in Study 1, high concentrations of Si were detected in the (paired) decalcified bone, being 1.89 ± 0.23 μg/g wet weight at 26 weeks (the same age as in Study 1), and there was relatively minor variation with age (range: 1.81–2.64 μg/g wet weight; or 47–71% of total bone Si concentration). Total silicon content of the decalcified bone varied further with age (Fig. 3a), as bone size changed markedly with growth, but as a percentage of total bone silicon it remained reasonably constant (50–58%) except at 43 weeks (27%). At 26 weeks it represented 58 ± 11% of the total bone Si content. Collagen concentration (mg/g wet weight) of the decalcified bone did not change markedly with age (Fig. 4a) but collagen content increased with age due to the increase in bone size (Fig. 4b). An average molar ratio of 1:6 (± 2) Si:collagen was estimated in the decalcified bone, using a molecular weight for type I collagen of 320 kDa (300–340 kDa (Silver and Trelstad, 1980, Zhang et al., 2005)). Boron was virtually undetected in the decalcified bone samples and this was not influenced by age, as per calcium (Fig. 3b & c).


Silicon and boron differ in their localization and loading in bone.

Jugdaohsingh R, Pedro LD, Watson A, Powell JJ - Bone Rep (2014)

Study 2: (a) Collagen concentration (mg/g wet weight; open circles) and (b) collagen content (mg; closed circles) of the decalcified tibia bones from female Sprague Dawley rats of different ages (weanling to adults). (b) The molar ratio of collagen:Si in the decalcified bone is shown (closed triangles). Data are means ± SE of n = 3–5 rat bones per age group.
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4643752&req=5

f0020: Study 2: (a) Collagen concentration (mg/g wet weight; open circles) and (b) collagen content (mg; closed circles) of the decalcified tibia bones from female Sprague Dawley rats of different ages (weanling to adults). (b) The molar ratio of collagen:Si in the decalcified bone is shown (closed triangles). Data are means ± SE of n = 3–5 rat bones per age group.
Mentions: As in Study 1, high concentrations of Si were detected in the (paired) decalcified bone, being 1.89 ± 0.23 μg/g wet weight at 26 weeks (the same age as in Study 1), and there was relatively minor variation with age (range: 1.81–2.64 μg/g wet weight; or 47–71% of total bone Si concentration). Total silicon content of the decalcified bone varied further with age (Fig. 3a), as bone size changed markedly with growth, but as a percentage of total bone silicon it remained reasonably constant (50–58%) except at 43 weeks (27%). At 26 weeks it represented 58 ± 11% of the total bone Si content. Collagen concentration (mg/g wet weight) of the decalcified bone did not change markedly with age (Fig. 4a) but collagen content increased with age due to the increase in bone size (Fig. 4b). An average molar ratio of 1:6 (± 2) Si:collagen was estimated in the decalcified bone, using a molecular weight for type I collagen of 320 kDa (300–340 kDa (Silver and Trelstad, 1980, Zhang et al., 2005)). Boron was virtually undetected in the decalcified bone samples and this was not influenced by age, as per calcium (Fig. 3b & c).

Bottom Line: Silicon and boron share many similarities, both chemically and biochemically, including having similar effects on bone, although their mechanisms of action are not known.Here we compared the loading of silicon and boron into bone, their localization and how they are influenced by age (growth & development), to obtain further clues as to the biological effects of these elements and, especially, to see if they behave the same or not.Highest silicon and lowest boron concentrations were found in the under-mineralized bone of younger rats and lowest silicon and highest boron concentrations were found in the fully mineralized bone of the adult rat.

View Article: PubMed Central - PubMed

Affiliation: MRC Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, United Kingdom.

ABSTRACT

Silicon and boron share many similarities, both chemically and biochemically, including having similar effects on bone, although their mechanisms of action are not known. Here we compared the loading of silicon and boron into bone, their localization and how they are influenced by age (growth & development), to obtain further clues as to the biological effects of these elements and, especially, to see if they behave the same or not. Bone samples were obtained from two different studies where female Sprague Dawley rats had been maintained on a normal maintenance diet for up to 43 weeks. Total bone elemental levels were determined by ICP-OES following microwave assisted acid digestion. Silicon and boron levels in the decalcified bones (i.e. the collagen fraction) were also investigated. Silicon and boron showed marked differences in loading and in their localization in bone. Highest silicon and lowest boron concentrations were found in the under-mineralized bone of younger rats and lowest silicon and highest boron concentrations were found in the fully mineralized bone of the adult rat. Overall, however total bone silicon content increased with age, as did boron content, the latter mirroring the increase in calcium (mineral) content of bone. However, whereas silicon showed equal distribution in the collagen and mineral fractions of bone, boron was exclusively localized in the mineral fraction. These findings confirm the reported association between silicon and collagen, especially at the early stages of bone mineralization, and show that boron is associated with the bone mineral but not connective tissues. These data suggest that silicon and boron have different biological roles and that one is unlikely, therefore, to substitute for the other, or at least boron would not substitute for Si in the connective tissues. Finally, we noted that silicon levels in the mineral fraction varied greatly between the two studies, suggesting that one or more nutritional factor(s) may influence the loading of Si into the mineral fraction of bone. This and the nature of the interaction between Si and collagen deserve further attention.

No MeSH data available.


Related in: MedlinePlus