title: [Establishment and evaluation of animal model for studying the effect of traumatic brain injury on bone fracture healing].
abstract: OBJECTIVE
  To establish a stable animal model for studying the effect of traumatic brain injury on bone fracture healing.
  
  
  METHODS
  Eighty adult male Sprague-Dawley rats were randomly divided into fracture combined brain injury group (A) and simple fracture group (B). Animals of the two groups were killed 6 hours, 1 week, 2 weeks, 1 month and 2 months after trauma, respectively. Their brain histopathology changes were observed and neurological severity scores (NSS, 0 through 25 from no injury to severe injury) determined to measure the brain injury after head trauma, and fracture-healing was assessed by measuring callus volume and X ray examination at the scheduled time points after trauma. The callus volumes were compared between the groups using independent-samples t test 1 week, 2 weeks, 1 month and 2 months after trauma respectively. A value of P<0.05 was considered statistically significant.
  
  
  RESULTS
  Ninety percent of the rats of group A presented with hemiplegia and the mortality rate was 10% (4/40) . The survived rats developed decorticated flexion deformity of the forelimbs, with behavioral depression, and lost some reflexes and muscle tone. The NSS were 10.83±1.94, 9.33±0.82, 8.17±1.17, 7.83±0.75 and 8.07±0.82 with 6 hours, 1 week, 2 weeks, 1 month and 2 months after trauma, respectively. It showed that the animals received moderate head injury, which tended to be stable from 2 weeks after trauma. Brain pathology showed that blood brain barrier was destroyed, and neurons were degenerative and necrotic at and around the trauma sites. The callus volumes(unit: mm(3)) of the two groups 1 week, 2 weeks, 1 month and 2 months after trauma were 60.03±28.05 and 32.80±11.04, 78.54±15.16 and 51.36±23.02, 93.01±10.65 and 72.38±20.38, 115.26±40.00 and 60.30±13.34, respectively. The callus volumes of the two groups 2 weeks, 1 month and 2 months after trauma were statistically and significantly different (P values were 0.036, 0.006 and 0.01 respectively), and there was no difference 1 week after trauma (P=0.065).
  
  
  CONCLUSIONS
  This model is capable of producing accurately quantified brain injury. The animal model is credible, stable and reproducible, so it is an effective platform for studying the effect of traumatic brain injury on fracture.
authors.affiliation: Department of Trauma and Orthopedics, Peking University Traffic Medicine Center, Beijing, China.
authors.forename: Xu hong
authors.initials: Xh
authors.lastname: Chen
authors.forename: Lu
authors.initials: L
authors.lastname: Bai
authors.forename: Hang-yu
authors.initials: HY
authors.lastname: Gu
authors.forename: Bo
authors.initials: B
authors.lastname: Chen
authors.forename: Qing-tian
authors.initials: QT
authors.lastname: Li
authors.forename: Shuai
authors.initials: S
authors.lastname: An
authors.forename: Zhi-yong
authors.initials: ZY
authors.lastname: Wang
authors.forename: Jiu-xu
authors.initials: JX
authors.lastname: Deng
authors.forename: Yu-hui
authors.initials: YH
authors.lastname: Kou
authors.forename: Pei-xun
authors.initials: PX
authors.lastname: Zhang
authors.forename: Xiao-feng
authors.initials: XF
authors.lastname: Yin
authors.forename: Na
authors.initials: N
authors.lastname: Han
authors.forename: Bao-guo
authors.initials: BG
authors.lastname: Jiang
mesh_terms: D000818:Animals; D001930:Brain Injuries / Q000150:complications* / Q000503:physiopathology; D004195:Disease Models, Animal; D017102:Fracture Healing / Q000502:physiology*; D050723:Fractures, Bone / Q000150:complications*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley