title: [MODEL ESTABLISHMENT, MRI AND PATHOLOGICAL FEATURES OF EARLY STEROID-INDUCED AVASCULAR NECROSIS OF FEMORAL HEAD IN RABBIT].
abstract: OBJECTIVE
  To establish an rabbit model of early steroid-induced avascular necrosis of the femoral head (SANFH) and evaluate its validity with MRI and pathological examination.
  
  
  METHODS
  Twenty 6-month-old rabbits (weighing, 2-3 kg) were randomly divided into 2 groups (control group and model group), 10 rabbits in each group. Dexamethasone sodium phosphate solution (10 mg/kg) was injected into bilateral gluteus in model group, and the same amount of saline was injected in control group, every 3 days for 14 times. General observation was done after modelling. Osteonecrosis was verified by pathological observation and MRI findings at 6 weeks.
  
  
  RESULTS
  After 6 weeks, rabbits did not show obvious changes in control group; increased hair removal, decreased food intake, and slight limp were observed in model group. The MRI results showed normal shape of the bilateral femoral head and no abnormal signals in control group; irregular shape of the bilateral femoral head and a slice of irregular abnormal signals were observed, and necrosis and cystolization of the subchondral bone and sparse changes of trabecular bone were shown in model group. General observation from coronal section of femoral head showed smooth red cartilage surface in control group; on the contrary, the cartilage surface of the femoral head became dull, thin even visible hemorrhage under articular cartilage and necrosis of the femoral head were observed. The histopathological examination indicated that trabecular bone of the femoral head in control group was massive, thick, and close and osteocytes in the bone lacunae had normal shapes. The osseous trabecular became thinner and broken; karyopyknosis of osteocytes and bone empty lacunae could be obviously seen in model. group. The rates of empty lacunae were 8.0% ± 0.5% in control group and 49.0% ± 0.3% in model group, showing significant difference (t = 21.940, P = 0.000).
  
  
  CONCLUSIONS
  Establishing a model of early SANFH through injecting short-term, shock, and high dose of dexamethasone, and it can been evaluated effectively with MRI and pathological examination.
authors.forename: Liyan
authors.initials: L
authors.lastname: Zhang
authors.forename: Xin
authors.initials: X
authors.lastname: Sun
authors.forename: Dan
authors.initials: D
authors.lastname: Tian
authors.forename: Rui
authors.initials: R
authors.lastname: Xu
authors.forename: Hao
authors.initials: H
authors.lastname: Lei
authors.forename: Jinhui
authors.initials: J
authors.lastname: Al
authors.forename: Bo
authors.initials: B
authors.lastname: Zhao
authors.forename: Jiying
authors.initials: J
authors.lastname: Chen
authors.forename: Wei
authors.initials: W
authors.lastname: Chai
authors.forename: Shoucheng
authors.initials: S
authors.lastname: Ma
authors.forename: Weijia
authors.initials: W
authors.lastname: Liu
authors.forename: Siyuan
authors.initials: S
authors.lastname: Shen
mesh_terms: D000818:Animals; D001808:Blood Vessels / Q000473:pathology*; D002358:Cartilage, Articular; D003907:Dexamethasone / Q000008:administration & dosage / Q000031:analogs & derivatives*; D005270:Femur Head / Q000098:blood supply* / Q000473:pathology; D005271:Femur Head Necrosis / Q000139:chemically induced / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008775:Methylprednisolone / Q000633:toxicity*; D011817:Rabbits; D011897:Random Allocation; D013256:Steroids
chemical_list: D013256:Steroids; C004180:dexamethasone 21-phosphate; D003907:Dexamethasone; D008775:Methylprednisolone