Closed-Head TBI Model of Multiple Morbidity

Abstract

Successful therapy for TBI disabilities awaits refinement in the understanding of TBI neurobiology, quantitative measurement of treatment-induced incremental changes in recovery trajectories, and effective translation to human TBI using quantitative methods and protocols that were effective to monitor recovery in preclinical models. Details of the specific neurobiology that underlies these injuries and effective quantitation of treatment-induced changes are beginning to emerge utilizing a variety of preclinical and clinical models (for reviews see (Morales et al., Neuroscience 136:971–989, 2005; Fujimoto et al., Neurosci Biobehav Rev 28:365–378, 2004; Cernak, NeuroRx 2:410–422, 2005; Smith et al., J Neurotrauma 22:1485–1502, 2005; Bose et al., J Neurotrauma 30:1177–1191, 2013; Xiong et al., Nat Rev Neurosci 14:128–142, 2013; Xiong et al., Expert Opin Emerg Drugs 14:67–84, 2009; Johnson et al., Handb Clin Neurol 127:115–128, 2015; Bose et al., Brain neurotrauma: molecular, neuropsychological, and rehabilitation aspects, CRC Press/Taylor & Francis, Boca Raton, 2015)). Preclinical models of TBI, essential for the efficient study of TBI neurobiology, benefit from the setting of controlled injury and optimal opportunities for biometric quantitation of injury and treatment-induced changes in the trajectories of disability. Several preclinical models are currently used, and each offer opportunities for study of different aspects of TBI primary and secondary injuries (for review see (Morales et al., Neuroscience 136:971–989, 2005; Xiong et al., Nat Rev Neurosci 14:128–142, 2013; Xiong et al., Expert Opin Emerg Drugs 14:67–84, 2009; Johnson et al., Handb Clin Neurol 127:115–128, 2015; Dixon et al., J Neurotrauma 5:91–104, 1988)). The closed-head, impact-acceleration model of TBI designed by Marmarou et al., 1994 (J Neurosurg 80:291–300, 1994), when used to produce mild to moderate TBI, produces diffuse axonal injuries without significant additional focal injuries of the brain (Morales et al., Neuroscience 136:971–989, 2005; Foda and Marmarou, J Neurosurg 80:301–313, 1994; Kallakuri et al., Exp Brain Res 148:419–424, 2003). Accordingly, use of this preclinical model offers an opportunity for (a) gaining a greater understanding of the relationships of TBI induced diffuse axonal injuries and associated long term disabilities, and (b) to provide a platform for quantitative assessment of treatment interactions upon the trajectories of TBI-induced disabilities. Using the impact acceleration closed head TBI model to induce mild/moderate injuries in the rat, we have observed and quantitated multiple morbidities commonly observed following TBI in humans (Bose et al., J Neurotrauma 30:1177–1191, 2013). This chapter describes methods and protocols used for TBI-induced multiple morbidity involving cognitive dysfunction, balance instability, spasticity and gait, and anxiety-like disorder.