Abstract
Postmenopausal women may benefit from dietary interventions in order to increase bone strength and prevent fractures. Dietary boron (B) may be beneficial for optimal calcium metabolism and, as a consequence, optimal bone metabolism. The present study evaluated the effects of boron, in the form of boric acid, with or without 17β-estradiol (E2) supplementation (via subcutaneous implant), in ovariectomized (OVX) aged 13-mo-old F-344 rats. Boric acid was administered by gavage at a subtoxic dose (8.7 mg B/kg/d) for 40 d. Results indicate that serum level of minerals as well as osteocalcin (a marker of bone resorption) are dependent to a greater extent on the hormonal status of the animals than on boron supplementation. Boron treatment increased the E2-induced elevation of urinary calcium and magnesium. Bone mineral density (BMD) of the L5 vertebra and proximal femur was highest in the E2-treated groups; no increase in BMD was conferred by boron treatment. By histomorphometry of the proximal tibial metaphysis, osteoblastic, osteoid, and eroded surfaces were significantly suppressed by E2 treatment, but not by boron treatment. In biomechanical testing of femur and vertebra, neither E2 nor boron treatment significantly increased bone strength. At the levels given, boron alone provided no protection against OVX-induced osteopenia. In addition, combination therapy (B + E2) provided no additional benefits over those of 17β-estradiol treatment alone in this aged rat model.
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J. R. Coughlin, Sources of human exposure: overview of water supplies as sources of boron, Biol. Trace Element Res. 66, 87–100 (1998).
W. W. Ku, R. E. Chapin, R. F. Moseman, et al., Tissue disposition of boron in male Fischer rats, Toxicol. Appl. Pharmacol. 111, 145–151 (1991).
R. F. Moseman, Chemical disposition of boron in animals and humans, Environ. Health Perspect. 102(Suppl. 7), 113–117 (1994).
H. McCoy, M. A. Kenney, C. Montgomery, et al., Relation of boron to the composition and mechanical properties of bone, Environ. Health Perspect. 102 (Suppl. 7), 49–53 (1994).
F. H. Nielsen, C. D. Hunt, L. M. Mullen, et al., Effect of dietary boron on mineral, estrogen, and testosterone metabolism in postmenopausal women, Faseb J. 1, 394–397 (1987).
J. H. Beattie and H. S. Peace, The influence of a low-boron diet and boron supplementation on bone, major mineral and sex steroid metabolism in postmenopausal women, Br. J. Nutr. 69, 871–884 (1993).
T. A. Armstrong and J. W. Spears, Effect of dietary boron on growth performance, calcium and phosphorus metabolism, and bone mechanical properties in growing barrows, J. Anim. Sci. 79, 3120–3127 (2001).
T. A. Armstrong, W. L. Flowers, J. W. Spears, et al., Long-term effects of boron supplementation on reproductive characteristics and bone mechanical properties in gilts, J. Anim. Sci. 80, 154–161 (2002).
C. D. Hunt and F. H. Nielsen, Dietary boron affects calcification in magnesium and cholecalciferol deficient chicks, Trace Elements Man Anim. 6, 275–276 (1987).
J. H. Wilson and P. L. Ruszler, Effects of dietary boron supplementation on laying hens, Br. Poult. Sci. 37, 723–729 (1996).
J. H. Wilson and P. L. Ruszler. Effects of boron on growing pullets, Biol. Trace Element Res. 56, 287–294 (1997).
R. E. Chapin, W. W. Ku, M. A. Kenney, et al., The effects of dietary boric acid on bone strength in rats, Biol. Trace Element Res. 66, 395–399 (1998).
M. H. Sheng, L. J. Taper, H. Veit, et al., Dietary boron supplementation enhanced the action of estrogen, but not that of parathyroid hormone, to improve trabecular bone quality in ovariectomized rats, Biol. Trace Element Res. 82, 109–123 (2001).
M. H. Sheng, L. J. Taper, H. Veit, et al., Dietary boron supplementation enhances the effects of estrogen on bone mineral balance in ovariectomized rats, Biol. Trace Element Res. 81, 29–45 (2001).
C. J. Price, P. L. Strong, M. C. Marr, et al., Developmental toxicity NOAEL and postnatal recovery in rats fed boric acid during gestation. Fundam. Appl. Toxicol. 32, 179–193 (1996).
H. B. Waynforth, Experimental and Surgical Techniques in the Rat, Academic, New York (1980).
J. D. Sibonga, N. H. Bell, and R. T. Turner, Evidence that ibuprofen antagonizes selective actions of estrogen and tamoxifen on rat bone, J. Bone Miner. Res. 13, 863–870 (1998).
A. M. Parfitt, M. K. Drezner, F. H. Glorieux, et al., Bone histomorphometry: standardization of nomenclature, symbols, and units. Report of the ASBMR Histomorphometry Nomenclature Committee. J. Bone Miner. Res. 2, 595–610 (1987).
C. H. Turner and D. B. Burr, Basic biomechanical measurements of bone: a tutorial, Bone 14, 595–608 (1993).
R. F. Moseman, R. E. Brink, C. W. Jameson, et al., Method development and validation for the determination of ppm levels of boron in rat tissue, Toxicologist 11, 278 (1991).
M. J. Jayo, T. C. Register, C. L. Hughes, et al., Effects of an oral contraceptive combination with or without androgen on mammary tissues: a study in rats, J. Soc. Gynecol. Invest. 7, 257–265 (2000).
J. F. McElroy and G. N. Wade, Short- and long-term effects of ovariectomy on food intake, body weight, carcass composition, and brown adipose tissue in rats, Physiol. Behav. 39, 361–365 (1987).
J. Erdmann, S. Storch, J. Pfeilschifter, et al., Effects of estrogen on the concentration of insulin-like growth factor-I in rat bone matrix. Bone 22, 503–507 (1998).
R. T. Turner, G. L. Evans, and G. K. Wakeley, Mechanism of action of estradiol on cancellous bone balance in tibiae of ovariectomized growing rats: inhibition of indices of bone formation and resorption, J. Bone Miner. Res. 8, 359–366 (1993).
C. D. Hunt, Biochemical Effects of physiological amounts of dietary boron, J. Trace Elements Exp. Med. 9, 185–213 (1996).
C. D. Hunt, Regulation of enzymatic activity: one possible role of dietary boron in higher animals and humans, Biol. Trace Element Res. 66, 205–225 (1998).
R. G. Erben, J. Eberle, K. Stahr, et al., Androgen deficiency induces high turnover osteopenia in aged male rats: a sequential histomorphometric study, J. Bone Miner. Res. 15, 1085–1098 (2000).
D. N. Kalu, C. C. Liu, R. R. Hardin, et al., The aged rat model of ovarian hormone deficiency bone loss, Endocrinology 124, 7–16 (1989).
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Gallardo-Williams, M.T., Maronpot, R.R., Turner, C.H. et al. Effects of boric acid supplementation on bone histomorphometry, metabolism, and biomechanical properties in aged female F-344 rats. Biol Trace Elem Res 93, 155–169 (2003). https://doi.org/10.1385/BTER:93:1-3:155
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DOI: https://doi.org/10.1385/BTER:93:1-3:155