title: The effect of chemical sympathectomy and stress on bone remodeling in adult rats.
abstract: OBJECTIVE
  Bone remodeling has recently been revealed to be under sympathetic nerve control. The role of the sympathetic nerve system is not clearly understood. The present study aim to explore the effect of chemical sympathectomy and stress on bone remodeling in adult rats.
  
  
  METHODS
  24 twelve-month-old Wistar rats were divided into three group (sympathectomy, stress and control). The sympathectomy and stress group rats were administered 6-hydroxydopamine (150 mg/kg each day) and saline (1 ml/kg each day) intraperitoneal respectively for one week and exposed to stress procedure for another three weeks. The stress procedure was mild, unpredictable footshock, administered for one hour once daily. Analysis of serum chemistry, microcomputed tomography, dual energy X-ray absorptiometry, biomechanical testing and bone histomorphometry were employed.
  
  
  RESULTS
  The stress group rats showed increased bone resorption in contrast to the sympathectomy and control group rats. The serum level of calcium and phosphorus cations and norepinephrine were enhanced, the cancellous bone volume and bone mineral density were reduced, bone mechanical property such as strength, ductility and toughness were weakened, the osteoclast counts and osteoclast surfaces were increased and the bone formatin rate were decreased significantly in the stress group rats in contrast to the other two groups rats. There was no significant difference of bone remodeling between the sympathectomy group and control group rats.
  
  
  CONCLUSIONS
  Our study showed stress-increased sympathetic nerve system activity enhanced bone resorption while chemical sympathectomy inhibited bone resorption under stress. We postulate sympathetic neurotransmitter and neuropepitide may play a role in regulating bone remodeling.
authors.affiliation: Department of Oral surgery, Fourth Military Medical University, People's Republic of China.
authors.forename: Kaijin
authors.initials: K
authors.lastname: Hu
authors.forename: Hongzhi
authors.initials: H
authors.lastname: Zhou
authors.forename: Guoliang
authors.initials: G
authors.lastname: Zhang
authors.forename: Ruifeng
authors.initials: R
authors.lastname: Qin
authors.forename: Rui
authors.initials: R
authors.lastname: Hou
authors.forename: Liang
authors.initials: L
authors.lastname: Kong
authors.forename: Yuxiang
authors.initials: Y
authors.lastname: Ding
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods; D000818:Animals; D015519:Bone Density; D016723:Bone Remodeling; D001862:Bone Resorption; D002118:Calcium / Q000097:blood; D004195:Disease Models, Animal; D004558:Electric Stimulation / Q000379:methods; D005528:Foot; D007274:Injections, Intraperitoneal; D008297:Male; D009483:Neuropsychological Tests; D009638:Norepinephrine / Q000097:blood; D010010:Osteoclasts; D016627:Oxidopamine; D010758:Phosphorus / Q000097:blood; D051381:Rats; D017208:Rats, Wistar; D013312:Stress, Physiological; D013563:Sympathectomy, Chemical; D013564:Sympathetic Nervous System / Q000378:metabolism* / Q000503:physiopathology*; D013565:Sympatholytics
chemical_list: D013565:Sympatholytics; D010758:Phosphorus; D016627:Oxidopamine; D002118:Calcium; D009638:Norepinephrine