Histological, immunohistochemical and ultrastructural study of secondary compressed spinal cord injury in a rat model
Abstract
Introduction. Spinal cord injury (SCI) is a life-disrupting condition in which the first few days are the most critical. Secondary conditions remain the main causes of death for people with SCI. The response of different cell types to SCI and their role at different times in the progression of secondary degeneration are not well understood. The aim of this study was to study the histopathological changes of compressed spinal cord injury (CSCI) in a rat model.
Material and methods. Forty adult male Sprague-Dawley rats were divided into four groups. In group I, the rats were left without any surgical intervention (control). In group II, the rats were subjected to laminectomy without spinal cord compression (sham-operated). In group III, the rats were sacrificed one day after CSCI. In group IV, the rats were sacrificed seven days after CSCI. The light microscopy was employed to study the morphology using H&E, osmic acid staining and immunohistochemistry to detect glial fibrillary acidic protein (GFAP). The electron microscopy was applied for ultrastructure study.
Results. Histopathological examination of the posterior funiculus of the white matter revealed minute hemorrhages and localized necrotic areas on day 1, which transformed to areas of cavitation and fibrinoid necrosis surrounded by a demarcating rim of numerous astrocytes by day 7. The mean percentage of area of GFAP expression increased significantly by day 7. Osmic acid staining revealed swollen nerve fibers after one day, while numerous fibers had been lost by day 7. An ultrastructure study revealed swollen redundant thinned myelin and myelin splitting, as well as degeneration of axoplasm on day 1. On day 7, layers of the myelin sheath were folded and wrinkled with partial or complete demyelination areas. The myelin lamellae were disorganized and loose. The G-ratio was significantly greater on day 1 than day 7 after CSCI.
Conclusions. In the rat model of CSCI details of the progressive spinal cord injury can be analyzed by morphological methods and may be helpful in the identification of the onset and type of clinical intervention.
Keywords: ratcompressed spinal cord injurymorphologyGFAPmyelin fiberselectron microscopy
References
- MFA. Spinal cord injuries in the developing world. In: International encyclopedia of rehabilitation. Buffalo University, New York; 2013.
- Fehlings MG, Tator CH. A review of experimental models of acute spinal cord injury. In: Spinal cord dysfunction: assessment. Oxford University, Oxford; 1988.
- Alhoseini MS, Movaghar VR. Orthopedics, physical medicine and rehabilitation animal models in traumatic spinal cord injury. In: Dionyssiotis Y. ed. Topics in paraplegia. InTech, Rijeka, Croatia; 2014.
- Lerman CT, Altevogt BM, Joy JE, Johnson RT. Progression of spinal cord injury. In: Spinal cord injury: progress, promise and priorities. The National Academies Press, Washington DC; 2005.
- Consortium for Spinal Cord Medicine. Early acute management in adults with spinal cord injury: a clinical practice guideline for health-care professionals. J Spinal Cord Med. 2008; 31(4): 403–479.
- Faulkner JR, Herrmann JE, Woo MJ, et al. Reactive astrocytes protect tissue and preserve function after spinal cord injury. J Neurosci. 2004; 24(9): 2143–2155.
- McGavern DB, Murray PD, Rodriguez M. Quantitation of spinal cord demyelination, remyelination, atrophy, and axonal loss in a model of progressive neurologic injury. J Neurosci Res. 1999; 58(4): 492–504.
- McGavern DB, Zoecklein L, Drescher KM, et al. Quantitative assessment of neurologic deficits in a chronic progressive murine model of CNS demyelination. Exp Neurol. 1999; 158(1): 171–181.
- Bakar B, Kose E, Ayva SK, et al. Effects of low-dose methotrexate in spinal cord injury in rats. Turk J Trauma Emergency Surg. 2013; 19(4): 285–293.
- Bancroft JD, Gamble M. Hematoxylin and eosin, connective tissue and stain, carbohydrates. In: Theory and practice in histological techniques. 6th ed. Churchill-Livingstone, Edinburgh; 2008: 121–186.
- Afsari ZH, Renno WM, Abd-El-Basset E. Alteration of glial fibrillary acidic proteins immunoreactivity in astrocytes of the spinal cord diabetic rats. Anat Rec (Hoboken). 2008; 291(4): 390–399.
- Hashish HA. Alteration of glial fibrillary acidic protein immunoreactivity in astrocytes of the cerebellum of diabetic rats and potential effect of insulin and ginger. Anat Physiol. 2015; 5(1).
- Wei Lp, He Fc, Chen Xw, et al. Osmic acid staining of myelin sheath in normal and regenerated peripheral nerves. Chin J Traumatol. 2007; 10(2): 86–89.
- Bozzola JJ, Russel LD. Electron microscopy: principles and techniques for biologists. 2nd ed. Jones and Bartlet Publishers, Sudbury; 1998.
- Chomiak T, Hu B. What is the optimal value of the g-ratio for myelinated fibers in the rat CNS? A theoretical approach. PLoS One. 2009; 4(11): e7754.
- Lebl DR, Hughes A, Cammisa FP, et al. Cervical spondylotic myelopathy: pathophysiology, clinical presentation, and treatment. HSS J. 2011; 7(2): 170–178.
- Tator CH, Fehlings MG. Review of the secondary injury theory of acute spinal cord trauma with emphasis on vascular mechanisms. J Neurosurg. 1991; 75(1): 15–26.
- Beattie MS, Bresnahan JC. Cell death, repair, and recovery of function after spinal cord contusion injuries in rats. In: Neurobiology of spinal cord injury. Humana Press, New Jersey; 2000.
- Yu WRu, Fehlings MG. Fas/FasL-mediated apoptosis and inflammation are key features of acute human spinal cord injury: implications for translational, clinical application. Acta Neuropathol. 2011; 122(6): 747–761.
- Kettenmann H, Ransom B. The concept of neuroglia: a historical prespective. In: Neuroglia. Oxford University Press, New York; 2005.
- Liu H, Shubayev VI. Matrix metalloproteinase-9 controls proliferation of NG2+ progenitor cells immediately after spinal cord injury. Exp Neurol. 2011; 231(2): 236–246.
- Tian Ds, Xie Mj, Yu Zy, et al. Cell cycle inhibition attenuates microglia induced inflammatory response and alleviates neuronal cell death after spinal cord injury in rats. Brain Res. 2007; 1135(1): 177–185.
- Wilhelmsson U, Bushong EA, Price DL, et al. Redefining the concept of reactive astrocytes as cells that remain within their unique domains upon reaction to injury. Proc Natl Acad Sci U S A. 2006; 103(46): 17513–17518.
- Fawcett JW, Asher RA. The glial scar and central nervous system repair. Brain Res Bull. 1999; 49(6): 377–391.
- Göritz C, Dias DO, Tomilin N, et al. A pericyte origin of spinal cord scar tissue. Science. 2011; 333(6039): 238–242.
- Fitch MT, Doller C, Combs CK, et al. Cellular and molecular mechanisms of glial scarring and progressive cavitation: in vivo and in vitro analysis of inflammation-induced secondary injury after CNS trauma. J Neurosci. 1999; 19(19): 8182–8198.
- Zhao X, Ahram A, Berman RF, et al. Early loss of astrocytes after experimental traumatic brain injury. Glia. 2003; 44(2): 140–152.
- Wei Lp, He Fc, Chen Xw, et al. Osmic acid staining of myelin sheath in normal and regenerated peripheral nerves. Chin J Traumatol. 2007; 10(2): 86–89.
- Vaquero J, Zurita M, Oya S, et al. Early administration of methylprednisolone decreases apoptotic cell death after spinal cord injury. Histol Histopathol. 2006; 21(10): 1091–1102.
- Huang SQ, Tang CL, Sun SQ, et al. Demyelination initiated by oligodendrocyte apoptosis through enhancing endoplasmic reticulum-mitochondria interactions and Id2 expression after compressed spinal cord injury in rats. CNS Neurosci Ther. 2014; 20(1): 20–31.
- Stikov N, Campbell JSW, Stroh T, et al. In vivo histology of the myelin G-ratio with magnetic resonance imaging. Neuroimage. 2015; 118: 397–405.
- Gu Z, Li F, Zhang YiP, et al. Apolipoprotein E mimetic promotes functional and histological recovery in lysolecithin-induced spinal cord demyelination in mice. J Neurol Neurophysiol. 2013; 2014(Suppl 12): 10.
- Totoiu MO, Keirstead HS. Spinal cord injury is accompanied by chronic progressive demyelination. J Comp Neurol. 2005; 486(4): 373–383.
