HISTOLOGY AND HISTOPATHOLOGY

Cellular and Molecular Biology

 

Review

Molecular mechanisms in the pathogenesis of traumatic brain injury

S.K. Ray1, C.E. Dixon2 and N.L. Banik1

1Department of Neurology, Clinical Science Building, Medical University of South Carolina, Charleston, SC, USA and
2Department of Neurosurgery, Brain Trauma Research Center, University of Pittsburgh, Pittsburgh, PA, USA

Offprint requests to: Naren L. Banik, Ph.D., Department of Neurology, Clinical Science Building, Medical University of South Carolina, 96 Jonathan Lucas Street, Suite 309, Charleston, SC 29425, USA. Fax: 843-792-8626. e-mail: baniknl@musc.edu

 

Summary. Traumatic brain injury (TBI) is a serious neurodisorder commonly caused by car accidents, sports related events or violence. Preventive measures are highly recommended to reduce the risk and number of TBI cases. The primary injury to the brain initiates a secondary injury process that spreads via multiple molecular mechanisms in the pathogenesis of TBI. The events leading to both neurodegeneration and functional recovery after TBI are generalized into four categories: (i) primary injury that disrupts brain tissues; (ii) secondary injury that causes pathophysiology in the brain; (iii) inflammatory response that adds to neurodegeneration; and (iv) repair-regeneration that may contribute to neuronal repair and regeneration to some extent following TBI. Destructive multiple mediators of the secondary injury process ultimately dominate over a few intrinsic protective measures, leading to activation of cysteine proteases such as calpain and caspase-3 that cleave key cellular substrates and cause cell death. Experimental studies in rodent models of TBI suggest that treatment with calpain inhibitors (e.g., AK295, SJA6017) and neurotrophic factors (e.g., NGF, BDNF) can prevent neuronal death and dysfunction in TBI. Currently, there is still no precise therapeutic strategy for the prevention of pathogenesis and neurodegeneration following TBI in humans. The search continues to explore new therapeutic targets and development of promising drugs for the treatment of TBI.. Histol. Histopathol. 17, 1137-1152 (2002)

Key words: TBI, Secondary injury, Calpain, Neurodegeneration, Calpain inhibitors


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