title: [Sequential expression of hypoxia-inducible factor 1alpha and its significance in secondary spinal cord injury].
abstract: OBJECTIVE
  To investigate the expression pattern of hypoxia-inducible factor 1alpha (HIF-1alpha) in experimental secondary spinal cord injury (SSCI) in rats and its potential effects on SSCI.
  
  
  METHODS
  A total of 66 SD rats (female or male) with weight (250 +/- 20) g were randomly divided into 3 groups: normal control group (group A, n = 6), pseudo injury group (group B, n = 6), and spinal cord injury (SCI) group (group C, n = 54). In group A, no treatment was given as normal control. In group B, only laminectomy was applied. In group C, laminectomy was applied and static compression model of SCI was built at T10 level. The expression of HIF-1alpha was measured with HE and immunohistochemical staining in groups A, B (1 hour after pseudo injury), and C (1, 3, 6, 12 hours and 1, 2, 3, 7, 14 days after SCI). Results All rats survived to the end of the experiment. HE staining showed that the spinal tissue of groups A and B were dense and the nucleus were round and big with light staining and clear nucleolus. The injured neuron at 1-12 hours after SCI of group C presented pyknosis and deep eosin staining. The swelling axon with bubbles and the disintegrated and disorganized medullary sheath in white matter appeared at 1-3 days after SCI. The hyperplasia of glial cells were obvious and gray matter cells were broken and apoptosis with cavities in injured spinal segment was observed at 7 and 14 days after SCI. Immunohistochemical staining showed that HIF-la was poorly expressed in group A and increased a little in group B. The positive expression in group C increased at 3 hours after SCI, which was found in spinal cord anterior horn neurons and a small amount of ganglion cells. It reached peak at 1 day, maintained at a high level during 1-3 days and then declined. At 14 days, it appeared only in a small amount of ganglion cells of white matter. There was no significant difference in the number of HIF-1alpha positive cells between groups A and B (t = 1.325, P = 0.137). The number of HIF-1alpha positive cells at each time point in group C was more than those in groups A and B (P < 0.05), and there were significant differences between all time points in group C (P < 0.05).
  
  
  CONCLUSIONS
  The expression of HIF-1alpha increases after SCI, it is related to the ischemia hypoxia after SSCI, and the expression pattern was correlated with the injury time.
authors.affiliation: Department of Orthopedic Surgery, Fengtian Hospital Affiliated to Shenyang Medical College, Shenyang Liaoning, 110024, P.R. China.
authors.forename: Qingfei
authors.initials: Q
authors.lastname: Niu
authors.forename: Changqing
authors.initials: C
authors.lastname: Jia
authors.forename: Nan
authors.initials: N
authors.lastname: Wang
authors.forename: Xiaochun
authors.initials: X
authors.lastname: Chen
authors.forename: Renjie
authors.initials: R
authors.lastname: Chi
authors.forename: Shuling
authors.initials: S
authors.lastname: Bai
mesh_terms: D000818:Animals; D000860:Hypoxia; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D007511:Ischemia; D051381:Rats; D017207:Rats, Sprague-Dawley; D013119:Spinal Cord Injuries / Q000209:etiology / Q000378:metabolism*
chemical_list: D051795:Hypoxia-Inducible Factor 1, alpha Subunit