title: Skeletal deterioration following ovarian failure: can some features be a direct consequence of estrogen loss while others are more related to physical inactivity?
abstract: Findings on experimental animals show that ovarian failure is accompanied by a decrease in motor activity. As mechanical loading has a vital role in the maintenance of skeletal health, our aim was to determine to what extent this decrease in motor activity contributes to ovariectomy-induced bone loss. Thirty-two female Wistar rats were ovariectomized or sham-operated and housed in standard cages or with access to running wheels for 36 weeks with their running distance monitored. Markers of bone turnover were assayed in the serum, and bone geometry, trabecular and cortical bone microarchitecture, mineralization degree, and biomechanical properties were assessed in the femur. Differences between groups were determined by one-way ANOVA. Although reduced motor activity and sex steroid deficiency both resulted in decreases in trabecular bone volume, trabecular number decreases were mostly associated with sex steroid deficiency, whereas trabecular thickness decreases were mostly associated with sedentary behavior. Cortical bone appeared to be more sensitive to variations in motor activity, whereas bone turnover rate and bone tissue mineralization degree seemed to be primarily affected by sex steroid deficiency, even though they were further aggravated by sedentary behavior. Increases in femur length were mostly a consequence of sex steroid deficiency, whereas femoral neck length was also influenced by sedentary behavior. Differences in mechanical properties resulted mostly from differences in physical activity. Both the direct effect of sex steroid deficiency and the indirect effect of motor activity changes are implicated in bone loss following ovariectomy.
authors.affiliation: CIAFEL, Faculty of Sport, University of Porto, Rua Dr. Plácido Costa 91, 4200-450, Porto, Portugal. helder.rmf@gmail.com.
authors.forename: Hélder
authors.initials: H
authors.lastname: Fonseca
authors.affiliation: CIAFEL, Faculty of Sport, University of Porto, Rua Dr. Plácido Costa 91, 4200-450, Porto, Portugal.
authors.forename: Daniel
authors.initials: D
authors.lastname: Moreira-Gonçalves
authors.affiliation: Escola Superior de Saude, Universidade de Aveiro, Aveiro, Portugal.
authors.forename: Francisco
authors.initials: F
authors.lastname: Amado
authors.affiliation: INEGI, Faculty of Engineering, University of Porto, Porto, Portugal.
authors.forename: José L
authors.initials: JL
authors.lastname: Esteves
authors.affiliation: CIAFEL, Faculty of Sport, University of Porto, Rua Dr. Plácido Costa 91, 4200-450, Porto, Portugal.
authors.forename: José Alberto
authors.initials: JA
authors.lastname: Duarte
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D001696:Biomechanical Phenomena; D001835:Body Weight; D015519:Bone Density; D016723:Bone Remodeling; D001842:Bone and Bones / Q000473:pathology* / Q000503:physiopathology; D004967:Estrogens / Q000172:deficiency*; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000473:pathology; D009043:Motor Activity; D009929:Organ Size; D016649:Primary Ovarian Insufficiency / Q000473:pathology* / Q000503:physiopathology; D011859:Radiography; D017208:Rats, Wistar
chemical_list: D015415:Biomarkers; D004967:Estrogens
keywords: Bone quality; Menopause; Osteoporosis; Sedentary behavior; Voluntary motor activity