title: Attenuation of hind-limb suspension-induced bone loss by curcumin is associated with reduced oxidative stress and increased vitamin D receptor expression.
abstract: Treatment with curcumin attenuated modeled microgravity-induced bone loss, possibly through abating oxidative stress and activating vitamin D receptor. Curcumin might be an effective countermeasure for microgravity-induced bone loss but remains to be tested in humans.
  
  
  BACKGROUND
  Bone loss is one of the most important complications for human crewmembers who are exposed to long-term microgravity in space and also for bedridden people. The aim of the current study was to elucidate whether treatment with curcumin attenuated bone loss induced by microgravity.
  
  
  METHODS
  We used hind-limb suspension (HLS) and rotary wall vessel bioreactor (RWVB) to model microgravity in vivo and in vitro, respectively. We investigated the effects of curcumin consumption (40 mg kg(-1) body weight day(-1), via daily oral gavages) on Sprague-Dawley (SD) rats exposed to HLS for 6 weeks. Then, we investigated the effects of incubation with curcumin (4 μM) on MC3T3-E1 and RAW264.7 cells cultured in RWVB.
  
  
  RESULTS
  Curcumin alleviated HLS-induced reduction of bone mineral density in tibiae and preserved bone structure in tibiae and mechanical strength in femurs. Curcumin alleviated HLS-induced oxidative stress marked by reduced malondialdehyde content and increased total sulfhydryl content in femurs. In cultured MC3T3-E1 cells, curcumin inhibited modeled microgravity-induced reactive oxygen species (ROS) formation and enhanced osteoblastic differentiation. In cultured RAW264.7 cells, curcumin reduced modeled microgravity-induced ROS formation and attenuated osteoclastogenesis. In addition, curcumin upregulated vitamin D receptor (VDR) expression in femurs of rats exposed to HLS and MC3T3-E1 cells exposed to modeled microgravity.
  
  
  CONCLUSIONS
  Curcumin alleviated HLS-induced bone loss in rats, possibly via suppressing oxidative stress and upregulating VDR expression.
authors.affiliation: Department of Orthopaedics, Provincial Hospital Affiliated to Shandong University, 324 JingWu Road, 250021, Jinan, China.
authors.forename: M
authors.initials: M
authors.lastname: Xin
authors.affiliation: Department of Orthopaedics, Provincial Hospital Affiliated to Shandong University, 324 JingWu Road, 250021, Jinan, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Department of Anaesthesiology, The Second Hospital Affiliated to Shandong University, 250033, Jinan, China.
authors.forename: D
authors.initials: D
authors.lastname: Zhang
authors.affiliation: The Medical School, The Australian National University, Acton, ACT 0200, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Wang
authors.affiliation: Research School of Physics and Engineering, The Australian National University, Acton, ACT 0200, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Chen
authors.affiliation: Department of Orthopaedics, Provincial Hospital Affiliated to Shandong University, 324 JingWu Road, 250021, Jinan, China. zhouds2014@hotmail.com.
authors.forename: D
authors.initials: D
authors.lastname: Zhou
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology / Q000627:therapeutic use*; D015519:Bone Density / Q000187:drug effects / Q000502:physiology; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D003474:Curcumin / Q000494:pharmacology / Q000627:therapeutic use*; D004353:Drug Evaluation, Preclinical / Q000379:methods; D005269:Femur / Q000187:drug effects / Q000503:physiopathology; D005786:Gene Expression Regulation / Q000187:drug effects; D019417:Hindlimb Suspension / Q000009:adverse effects / Q000379:methods; D008297:Male; D010006:Osteoblasts / Q000187:drug effects / Q000473:pathology; D010012:Osteogenesis / Q000187:drug effects / Q000502:physiology; D010024:Osteoporosis / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D018384:Oxidative Stress / Q000187:drug effects* / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D018167:Receptors, Calcitriol / Q000096:biosynthesis / Q000187:drug effects* / Q000235:genetics; D013977:Tibia / Q000187:drug effects / Q000503:physiopathology; D014893:Weightlessness / Q000009:adverse effects
chemical_list: D000975:Antioxidants; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D018167:Receptors, Calcitriol; D003474:Curcumin
keywords: Microgravity; Orally; Rats; Reactive oxygen species; Rotary wall vessel bioreactor