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Changes In Femoral Bone Geometry Compensate The Lower Bone Mass And Mineralization Degree In Ovariectomized Wistar Rats
Author(s) -
Fonseca Helder,
Moreira-Gonçalves Daniel,
Ferreira Rita,
Amado Francisco,
Mota Maria Paula,
Duarte José Alberto
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.729.7
Subject(s) - ovariectomized rat , femur , bone tissue , bone remodeling , femoral neck , cortical bone , osteoporosis , bone resorption , endocrinology , medicine , bone density , estrogen , diaphysis , bone histomorphometry , chemistry , anatomy , trabecular bone , surgery
Bone strength depends on a set of interdependent factors ranging from tissue properties to whole bone structural organization, and estrogen appears to influence several of these factors. Our goal was to determine the effects of estrogen loss on both tissue and geometrical femur properties and to appreciate their expression in whole bone strength. Twenty five Wistar rats were ovariectomized (OVX, n=13) or sham operated (SHAM, n=12) at 5 months and sacrificed at 14 months of age. Another group of rats (5 months) was sacrificed as baseline control (BSL, n=7). Serum bone resorption markers were higher while femur calcium content was lower in OVX compared to SHAM. Histomorphometry revealed a lower cortical bone thickness (Ct.Th) and trabecular volume in OVX proximal femur as well as a lower Ct.Th at the diaphysis. However, bone width, bone length, and femoral neck length were higher in OVX than in SHAM and all these variables correlated with femur ultimate load (U L ) following biomechanical testing. There were no differences in femoral neck and mid‐diaphysis U L between OVX and SHAM. However, bone tissue intrinsic properties were lower in OVX compared to SHAM. Estrogen loss leads to a decrease in bone tissue quality resulting in lower intrinsic bone tissue properties. Yet, compensatory geometrical adaptations also occur that prevent bone strength from declining. FCT grants PTDC/DES/103047/2008 and SFRH/BPD/78259/2011.