Tags

Type your tag names separated by a space and hit enter

Early estrogen replacement therapy reverses the rapid loss of trabecular bone volume and prevents further deterioration of connectivity in the rat.
J Bone Miner Res. 1999 Feb; 14(2):206-14.JB

Abstract

To evaluate the ability of estrogen replacement therapy (ERT) to prevent changes in trabecular bone volume (BV/TV) and connectivity beginning either at ovariectomy (OVX) or 5-13 days after OVX in adult female rats, the right proximal tibial was examined by three-dimensional X-ray tomographic microscopy (XTM) in vivo. Animals had XTM scans of the right tibia and then were randomized into six groups (n = 9). Groups 2-6 had bilateral (OVX), while group 1 was sham-ovariectomized (OVXd) on day 0. Animals were treated with vehicle (groups 1 and 2) or 17beta-estradiol therapy (ERT) at 10 microg/kg three times per week starting at days 0, 5, 8, and 13 post-OVX (groups 3, 4, 5, and 6), until day 50 when they were rescanned by XTM and sacrificed. Trabecular bone structural variables were calculated from XTM data (BV/TVx and beta1/BV/TVx) and standard histomorphometry. Trabecular bone volume (BV/TVx) and the trabecular connections per cubic millimeter of trabecular bone (beta1/BV/TVx) were maintained in both sham-OVXd animals and OVX animals given ERT from the time of OVX. However, OVX + vehicle-treated animals lost 54% BV/TVx and 46% beta1/BV/TVx (p < 0. 01 from day 0). BV/TVx and beta1/BV/TVx decreased rapidly post-OVX to -22% and -25% at day 13 (p < 0.01 from day 0). ERT initiated at day 5, 8, and 13 post-OVX restored BV/TVx to baseline values at day 50 by modestly increasing trabecular plate thickness; however, beta1/BV/TVx was reduced in all OVX groups when compared with their baseline values. ERT also caused a significant reduction in bone turnover compared with OVX + vehicle; however, resorption was suppressed more than formation. These results demonstrate that ERT can restore the lost trabecular bone, but not trabecular connectivity, that occurs soon after OVX by allowing bone formation to continue in previously activated bone remodeling units while suppressing the production of new remodeling units. This may be the mechanism by which prompt intervention with estrogen and other antiresorptive agents can restore bone mass that has been lost from the increase in remodeling space, and thereby reduce the risk of osteoporotic fractures in postmenopausal women.

Authors+Show Affiliations

Department of Medicine, University of California at San Francisco, San Francisco, 94143, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

9933474

Citation

Lane, N E., et al. "Early Estrogen Replacement Therapy Reverses the Rapid Loss of Trabecular Bone Volume and Prevents Further Deterioration of Connectivity in the Rat." Journal of Bone and Mineral Research : the Official Journal of the American Society for Bone and Mineral Research, vol. 14, no. 2, 1999, pp. 206-14.
Lane NE, Haupt D, Kimmel DB, et al. Early estrogen replacement therapy reverses the rapid loss of trabecular bone volume and prevents further deterioration of connectivity in the rat. J Bone Miner Res. 1999;14(2):206-14.
Lane, N. E., Haupt, D., Kimmel, D. B., Modin, G., & Kinney, J. H. (1999). Early estrogen replacement therapy reverses the rapid loss of trabecular bone volume and prevents further deterioration of connectivity in the rat. Journal of Bone and Mineral Research : the Official Journal of the American Society for Bone and Mineral Research, 14(2), 206-14.
Lane NE, et al. Early Estrogen Replacement Therapy Reverses the Rapid Loss of Trabecular Bone Volume and Prevents Further Deterioration of Connectivity in the Rat. J Bone Miner Res. 1999;14(2):206-14. PubMed PMID: 9933474.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Early estrogen replacement therapy reverses the rapid loss of trabecular bone volume and prevents further deterioration of connectivity in the rat. AU - Lane,N E, AU - Haupt,D, AU - Kimmel,D B, AU - Modin,G, AU - Kinney,J H, PY - 1999/2/5/pubmed PY - 1999/2/5/medline PY - 1999/2/5/entrez SP - 206 EP - 14 JF - Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research JO - J. Bone Miner. Res. VL - 14 IS - 2 N2 - To evaluate the ability of estrogen replacement therapy (ERT) to prevent changes in trabecular bone volume (BV/TV) and connectivity beginning either at ovariectomy (OVX) or 5-13 days after OVX in adult female rats, the right proximal tibial was examined by three-dimensional X-ray tomographic microscopy (XTM) in vivo. Animals had XTM scans of the right tibia and then were randomized into six groups (n = 9). Groups 2-6 had bilateral (OVX), while group 1 was sham-ovariectomized (OVXd) on day 0. Animals were treated with vehicle (groups 1 and 2) or 17beta-estradiol therapy (ERT) at 10 microg/kg three times per week starting at days 0, 5, 8, and 13 post-OVX (groups 3, 4, 5, and 6), until day 50 when they were rescanned by XTM and sacrificed. Trabecular bone structural variables were calculated from XTM data (BV/TVx and beta1/BV/TVx) and standard histomorphometry. Trabecular bone volume (BV/TVx) and the trabecular connections per cubic millimeter of trabecular bone (beta1/BV/TVx) were maintained in both sham-OVXd animals and OVX animals given ERT from the time of OVX. However, OVX + vehicle-treated animals lost 54% BV/TVx and 46% beta1/BV/TVx (p < 0. 01 from day 0). BV/TVx and beta1/BV/TVx decreased rapidly post-OVX to -22% and -25% at day 13 (p < 0.01 from day 0). ERT initiated at day 5, 8, and 13 post-OVX restored BV/TVx to baseline values at day 50 by modestly increasing trabecular plate thickness; however, beta1/BV/TVx was reduced in all OVX groups when compared with their baseline values. ERT also caused a significant reduction in bone turnover compared with OVX + vehicle; however, resorption was suppressed more than formation. These results demonstrate that ERT can restore the lost trabecular bone, but not trabecular connectivity, that occurs soon after OVX by allowing bone formation to continue in previously activated bone remodeling units while suppressing the production of new remodeling units. This may be the mechanism by which prompt intervention with estrogen and other antiresorptive agents can restore bone mass that has been lost from the increase in remodeling space, and thereby reduce the risk of osteoporotic fractures in postmenopausal women. SN - 0884-0431 UR - https://www.unboundmedicine.com/medline/citation/9933474/Early_estrogen_replacement_therapy_reverses_the_rapid_loss_of_trabecular_bone_volume_and_prevents_further_deterioration_of_connectivity_in_the_rat_ L2 - https://doi.org/10.1359/jbmr.1999.14.2.206 DB - PRIME DP - Unbound Medicine ER -