Biomechanics of nerve injury in traumatic and blast injury

By integrating biological, engineering, and computational methods we are interested in developing biomechanical models of brain and spinal cord tissue to better understand the structural damage, and more importantly, capable of predicting functional loss resulting from various trauma, such as mechanical (compression, contusion) and blast injury.

Mechanical or blast injuries to the brain and spinal cord often results in tissue damage that lead to various functional loss. Effective prognosis and treatment of these types of injury is virtually non-existent because of poor understanding of the mechanisms of injury and the mechanical properties of the CNS tissues. Computational models are a valuable tool that can predict the extent of structural damage to the spinal cord and the consequent loss of nerve function. Development of an effective model requires a rigorous interdisciplinary effort that takes into account the anatomical mechanisms of injury as well as the mechanical behavior of the tissue. Engineers can characterize the tissue properties and biologists can monitor anatomical and functional changes. These disciplines have been brought together to in our lab to build an effective model. We have established an interdisciplinary research team working together to understand the mechanisms of various traumatic injuries and establish models that can predict the severity of tissue damage at given external load and also guild treatments.

Selected publications related to the topic:

Shi, R. and Blight, A.R. Compression injury of mammalian spinal cord in vitro and the dynamics of action potential conduction failure. J. Neurophysiol. 76:1572-1580, 1996.

Controls of membrane sealing in injured mammalian spinal cord axons. J. Neurophysiol. 84: 1763-1769, 2000.
Shi, R. and Pryor, J.D. Temperature dependence of membrane sealing in mammalian spinal cord axons. Neuroscience 98: 157-166, 2000.

Shi, R., Qiao, X., Emerson, N. and Malcom, A. Dimethylsulfoxide enhances CNS neuronal plasma membrane resealing after injury in low temperature or low calcium.
J. Neurocytol. 30: 829-839, 2001.

Shi, R. and Pryor J.D. Pathological changes of isolated spinal cord axons in response to mechanical stretch. Neuroscience 110: 765-777, 2002.

Li, M. and Shi. R. A device for the electrophysiological recording of peripheral nerves in response to stretch. J. Neurosci. Meth. 154: 102-108. 2006.

Shi, R. and Whitebone, j. conduction deficits and membrane disruption of spinal cord axons as a function of magnitude and rate of strain. J. Neurophysiol. 95, 3384-3390. 2006.

Li, M. and Shi, R. Stretch induced conduction deficits in Guinea Pig ex-vivo nerve J. Biomechanics. 40: 569-578. 2007.

Galle, B., Ouyang, H., Shi, R., and Nauman, E. Correlation between tissue-level stress and strains and cellular damage within the guinea pig spinal cord white matter. J. Biomechanics. 40: 3029-3033. 2007.

Ouyang, H., Galle, B., Li, J., Nauman, E., and Shi, R. Biomechanics of spinal cord injury: a multimodal investigation using ex vivo guinea pig spinal cord white matter. J Neurotrauma. 25: 19-29. 2008

Ouyang, H., Galle, B., Li, J., Nauman, E., and Shi, R. Critical roles of decompression in functional recovery of ex vivo spinal cord white matter. Journal of Neurosurgery Spine. 10: 161-170. 2009.

Ouyang, H., Sun, W., Fu, Y., Li, J., Cheng, J., Nauman, E., and Shi, R. Compression induces acute demyelination and potassium channel exposure in spinal cord. J. Neurotrauma. 27: 1109-20. 2010.

Galle, B., Ouyang, H., Shi, R., and Nauman, E. A transversely isotropic constitutive model of excised guinea pig spinal cord white matter. J. Biomechanics. 43: 2839-43. 2010

Connell, S, Ouyang, H., and Shi, R. Modeling Blast Induced Neurotruama in Isolated Spinal Cord White Matter. J Medical Systems. 35: 765-770, 2011.

Connell, S., Gao, J., Chen, J., and Shi, R. Novel model to investigate blast injury in the central nervous system. J Neurotrauma. 28: 1229-1236, 2011.

Rickett, T., Connell, S., Bastijanic , J., Hegde, S., and Shi, R. "Functional and Mechanical Evaluation of Nerve Stretch Injury," J Medical Systems. 35: 787-793, 2011.

Sun, W., Fu, Y., Shi, Y., Cheng, J., Cao, P., and Shi, R. Paranodal myelin damage following acute stretch in guinea pig spinal cord. J Neurotrauma. In press