Experimental spinal cord injury: quantitation of axonal damage by automated image analysis

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✓ The severity of acute experimental spinal cord injury in rats was assessed quantitatively with the aid of an automated image analyzer by measuring the amount of degenerating axons that had developed distal to the site of mechanical insult. Spinal cord injury was produced in adult male rats by epidural compression at T-11 with a Biemer vascular clip. On the 7th postoperative day, the animals were graded according to the degree of hindlimb motor deficit, as follows: Grade 0: normal (three rats); Grade 1: crawling with difficulty (10 rats); Grade 2: some voluntary movement (nine rats); and Grade 3: no voluntary movement (nine rats). The rats were then sacrificed. The L-6 segment was chosen for selective silver impregnation of degenerating axons by the Fink-Heimer method.

Silver grains, representing degenerating axons and their terminals, were accumulated in the descending tracts and in Rexed's laminae VII and VIII. The extent of axonal damage was expressed by the percentage of the area occupied by silver grains in Rexed's lamina VIII. The area occupied by silver grains was 17.0% (mean) in Grade 0 rats, 22.3% ± 2.63% (mean ± standard deviation) in Grade 1 rats, 28.7% ± 3.35% in Grade 2 rats, and 35.9% ± 2.76% in Grade 3 rats. The severity in Grade 3 rats was close to that of rats with transected cords (37.6% ± 0.89%). The differences among the groups were statistically significant (p < 0.001). This method may serve as a useful tool for the objective assessment of therapeutic modalities in large series of small experimental animals.

Article Information

Address reprint requests to: Yuzo Iwasaki, M.D., Department of Neuropathology, Institute of Brain Diseases, Tohoku University School of Medicine, 1-1 Seiryo-Machi Sendai 980, Japan.

© AANS, except where prohibited by US copyright law.

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Figures

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    Sections of the L-6 segment on the 7th postoperative day. Arrows indicate the cell Group X of Onuf. Fink-Heimer method, × 30. Left: Section from a laminectomized but uninjured spinal cord showing no apparent deposition of silver grains in either white or gray matter. The dark curvilinear shadows are blood vessel walls. Right: Section from an animal that had undergone complete cord transection. The descending tracts in the white matter were almost entirely replaced by dense accumulations of silver grains. In the gray matter, the silver grains were markedly concentrated in Rexed's laminae VII and VIII.

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    Photomicrographs of sections from animals subjected to compression spinal cord injury. Preparations of Rexed's lamina VIII of the L-6 segment show the difference in the density of silver grains between Grade 1 (left) and Grade 3 (right) animals. The cell Group X of Onuf (arrows) is mostly devoid of degenerating axon terminals. Fink-Heimer method, × 150.

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    Photomicrographs showing the image transferred to the automated analyzer (left) and its binary image (right). The ratio of white area representing silver grains to the area encircled (5.174 × 10−2 sq mm) was computer-calculated. Arrows indicate the cell Group X of Onuf. Fink-Heimer method, × 180.

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    The results of morphometry of the area studied. The percentage of the area occupied by silver grains is indicated along the vertical scale and the clinical grades are shown along the horizontal scale. Each point represents an arithmetic mean of three sections made from the L-6 segment. Values shown are means ± standard deviations.

References

  • 1.

    Banik NLHogan ELPowers JMet al: Degradation of cytoskeletal proteins in experimental spinal cord injury. Neurochem Res 7:146514751982Banik NL Hogan EL Powers JM et al: Degradation of cytoskeletal proteins in experimental spinal cord injury. Neurochem Res 7:1465–1475 1982

    • Search Google Scholar
    • Export Citation
  • 2.

    Braughler JMHall ED: Effects of multi-dose methyl-prednisolone sodium succinate administration on injured cat spinal cord neurofilament degradation and energy metabolism. J Neurosurg 61:2902951984Braughler JM Hall ED: Effects of multi-dose methyl-prednisolone sodium succinate administration on injured cat spinal cord neurofilament degradation and energy metabolism. J Neurosurg 61:290–295 1984

    • Search Google Scholar
    • Export Citation
  • 3.

    Brown LT Jr: Projections and termination of the corticospinal tract in rodents. Exp Brain Res 13:4324501971Brown LT Jr: Projections and termination of the corticospinal tract in rodents. Exp Brain Res 13:432–450 1971

    • Search Google Scholar
    • Export Citation
  • 4.

    de la Torre JC: Spinal cord injury. Review of basic and applied research. Spine 6:3153351981de la Torre JC: Spinal cord injury. Review of basic and applied research. Spine 6:315–335 1981

    • Search Google Scholar
    • Export Citation
  • 5.

    Eidelberg E: Grading animals with spinal cord injury. J Neurosurg 43:6461975 (Letter)Eidelberg E: Grading animals with spinal cord injury. J Neurosurg 43:646 1975 (Letter)

    • Search Google Scholar
    • Export Citation
  • 6.

    Eidelberg EStaten EWatkins JCet al: A model of spinal cord injury. Surg Neurol 6:35381976Eidelberg E Staten E Watkins JC et al: A model of spinal cord injury. Surg Neurol 6:35–38 1976

    • Search Google Scholar
    • Export Citation
  • 7.

    Fink RPHeimer L: Two methods for selective silver impregnation of degenerating axons and their synaptic endings in the central nervous system. Brain Res 4:3693741967Fink RP Heimer L: Two methods for selective silver impregnation of degenerating axons and their synaptic endings in the central nervous system. Brain Res 4:369–374 1967

    • Search Google Scholar
    • Export Citation
  • 8.

    Jane JASteward OGennarelli T: Axonal degeneration induced by experimental noninvasive minor head injury. J Neurosurg 62:961001985Jane JA Steward O Gennarelli T: Axonal degeneration induced by experimental noninvasive minor head injury. J Neurosurg 62:96–100 1985

    • Search Google Scholar
    • Export Citation
  • 9.

    Konishi ASato MMizuno Net al: An electron microscope study of the areas of the Onuf's nucleus in the cat. Brain Res 156:3333381978Konishi A Sato M Mizuno N et al: An electron microscope study of the areas of the Onuf's nucleus in the cat. Brain Res 156:333–338 1978

    • Search Google Scholar
    • Export Citation
  • 10.

    Molander CXu QGrant G: The cytoarchitectonic organization of the spinal cord in the rat. I. The lower thoracic and lumbosacral cord. J Comp Neurol 230:1331411984Molander C Xu Q Grant G: The cytoarchitectonic organization of the spinal cord in the rat. I. The lower thoracic and lumbosacral cord. J Comp Neurol 230:133–141 1984

    • Search Google Scholar
    • Export Citation
  • 11.

    Rexed B: Some aspects of the cytoarchitectonics and synaptology of the spinal cord. Prog Brain Res 11:58921964Rexed B: Some aspects of the cytoarchitectonics and synaptology of the spinal cord. Prog Brain Res 11:58–92 1964

    • Search Google Scholar
    • Export Citation
  • 12.

    Rivlin ASTator CH: Effect of duration of acute spinal cord compression in a new acute cord injury model in the rat. Surg Neurol 10:39431978Rivlin AS Tator CH: Effect of duration of acute spinal cord compression in a new acute cord injury model in the rat. Surg Neurol 10:39–43 1978

    • Search Google Scholar
    • Export Citation
  • 13.

    Rivlin ASTator CH: Objective clinical assessment of motor function after experimental spinal cord injury in the rat. J Neurosurg 47:5775811977Rivlin AS Tator CH: Objective clinical assessment of motor function after experimental spinal cord injury in the rat. J Neurosurg 47:577–581 1977

    • Search Google Scholar
    • Export Citation
  • 14.

    West JRDewey SL: Mossy fiber sprouting in the fascia dentata after unilateral entorhinal lesions: quantitative analysis using computer-assisted image processing. Neuroscience 13:3773841984West JR Dewey SL: Mossy fiber sprouting in the fascia dentata after unilateral entorhinal lesions: quantitative analysis using computer-assisted image processing. Neuroscience 13:377–384 1984

    • Search Google Scholar
    • Export Citation

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