Rodent Model of Chronic Central Pain After Spinal Cord Contusion Injury and Effects of Gabapentin

Abstract

Spinal cord injury (SCI) often results in abnormal pain syndromes in patients. We present a recently developed SCI mammalian model of chronic central pain in which the spinal cord is contused at T8 using the NYU impactor device (10-g rod, 2.0-mm diameter, 12.5-mm drop height), an injury which is characterized behaviorally as moderate. Recovery of locomotor function was assessed with an open field test and scored using the open field test scale (BBB scale). Somatosensory tests of paw withdrawal responses accompanied by supraspinal responses to both mechanical punctate (von Frey hairs) and nonpunctate (4 mm diameter blunt probe) as well as thermal (radiant heat) peripheral stimuli were performed. Comparisons at the level of the individual animal between precontusion and postcontusion responses indicated significant increases in reactions to low threshold punctate mechanical stimuli, non-punctate stimuli and thermal stimuli (p < 0.05). To demonstrate the validity of this model as a central pain model, gabapentin, an agent used clinically for central pain, was given i.p. at 10 or 30 mg/kg. Gabapentin treatment significantly and reversibly changed the responses, consistent with the attenuation of the abnormal sensory behavior, and the attenuated responses lasted for the duration of the drug effect (up to 6 h). These results support the use of the spinal contusion model in the study of chronic central pain after SCI.

Alleviation of chronic pain following rat spinal cord compression injury with multimodal actions of huperzine A

“…Animal models of neuropathic pain after SCI are rare, so that a standard battery of evaluable neuropathic pain behaviors specific to rodent SCI does not truly exist (29,36). As an index of neuropathic pain below the SCI level, we used hindpaw hypersensitivity, which is widely accepted as a general measure of rodent neuropathic pain behavior in peripheral mononeuropathy models involving injury to hindlimb nerves but also has been used in SCI models (2,(4)(5)(6)29). The moderate degree of compression injury in our model appeared to be ideally suited to the measurement of hindpaw-withdrawal thresholds, because the return of reflexive hindpaw function before reaching the chronic injury phase (Fig.…”

Common animal models for spasticity and pain

“…However, contusion injury and central cord lesions have demonstrated lowered thresholds for nocifensive behavior with stimulation of at-level dermatomes and tactile allodynia in skin responses [138,139], and in a few cases, use of paw withdrawal responses or vocalization to paw pressure in a moderate contusion [139][140][141]. Both contusion and transection have better used biochemical and electrophysiologic methods to assess markers of at-level neuropathic pain [41,[142][143][144][145].…”

Spinal cord injury causes rapid osteoclastic resorption and growth plate abnormalities in growing rats (SCI-induced bone loss in growing rats)

“…It has been used to determine the effects of various treatments on spinal cord recovery [24,25] as well as to study common sequelae of SCI ranging from neuropathic pain [26,27] to neurogenic bladder [28,29]. However, there are no studies of bone loss following contusion injury in rodents.…”