Characterization of traumatic spinal cord injury model in relation to neuropathic pain in the rat.

ABSTRACT

Purpose/aim: Neuropathic pain following spinal cord injury (SCI) has a tremendous impact on patient's quality of life, and frequently is the most limiting aspect of the disease. In view of the severity of this condition and the absence of effective treatments, the establishment of a reliable animal model that reproduces neuropathic pain after injury is crucial for a better understanding of the pathophysiology and for the development of new therapeutic strategies. Thus, the objective of the present study was to standardize the traumatic SCI model in relation to neuropathic pain. MATERIALS AND METHODS: Wistar rats were submitted to SCI of mild intensity (pendulum height 12.5 mm) or moderate intensity (pendulum height 25 mm) using the New York University Impactor equipment. Behavioural assessment was performed during 8 weeks. Thereafter, spinal cords were processed for immunohistochemistry. RESULTS: The animals of the moderate injury group in comparison with mild injury had a greater motor function deficit, worse mechanical allodynia, and latter bladder recovery; moreover, histological analysis revealed more extensive lesions with lower neuronal population. CONCLUSIONS: Our study suggests that moderate SCI causes a progressive and long-lasting painful condition (at least 8 weeks), in addition to motor impairment, and thus represents a reliable animal model for the study of chronic neuropathic pain after SCI.