title: Reduced bone mass accrual in mouse model of repetitive mild traumatic brain injury.
abstract: Traumatic brain injury (TBI) can affect bone by influencing the production/actions of pituitary hormones and neuropeptides that play significant regulatory roles in bone metabolism. Previously, we demonstrated that experimental TBI exerted a negative effect on the skeleton. Since mild TBI (mTBI) accounts for the majority of TBI cases, this study was undertaken to evaluate TBI effects using a milder impact model in female mice. Repetitive mTBI caused microhemorrhaging, astrocytosis, and increased anti-inflammatory protective actions in the brain of the impacted versus control mice 2 wk after the first impact. Serum levels of growth regulating insulin-like growth factor 1 (IGF-I) were reduced by 28.9%. Bone mass was reduced significantly in total body as well as individual skeletons. Tibial total cortical density was reduced by 7.0%, which led to weaker bones, as shown by a 31.3% decrease in femoral size adjusted peak torque. A 27.5% decrease in tibial trabecular bone volume per total volume was accompanied by a 34.3% (p = 0.07) decrease in bone formation rate (BFR) per total area. Based on our data, we conclude that repetitive mTBI exerted significant negative effects on accrual of both cortical and trabecular bone mass in mice caused by a reduced BFR.
authors.forename: Hongrun
authors.initials: H
authors.lastname: Yu
authors.forename: Jon E
authors.initials: JE
authors.lastname: Wergedal
authors.forename: Charles H
authors.initials: CH
authors.lastname: Rundle
authors.forename: Subburaman
authors.initials: S
authors.lastname: Mohan
mesh_terms: D000818:Animals; D001835:Body Weight; D015519:Bone Density; D001930:Brain Injuries / Q000235:genetics / Q000473:pathology / Q000503:physiopathology*; D002135:Calcium-Binding Proteins / Q000235:genetics; D004195:Disease Models, Animal; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000473:pathology*; D015870:Gene Expression; D005904:Glial Fibrillary Acidic Protein; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008840:Microfilament Proteins / Q000235:genetics; D009419:Nerve Tissue Proteins / Q000235:genetics; D009929:Organ Size; D010012:Osteogenesis; D011859:Radiography; D012008:Recurrence; D013977:Tibia / Q000000981:diagnostic imaging / Q000473:pathology*
chemical_list: C491049:Aif1 protein, mouse; D002135:Calcium-Binding Proteins; D005904:Glial Fibrillary Acidic Protein; D018840:HSP70 Heat-Shock Proteins; D008840:Microfilament Proteins; D009419:Nerve Tissue Proteins; C528900:glial fibrillary astrocytic protein, mouse; D007334:Insulin-Like Growth Factor I
keywords: bone mineral content; bone mineral density; histology; histomorphometry; mice; micro–computed tomography; mild traumatic injury; torsion test; traumatic brain injury; weight drop model