In Vivo Neuroprotective Effect of Histidine-Tryptophan-Ketoglutarate Solution in an Ischemia/Reperfusion Spinal Cord Injury Animal Model

Evaluation of spinal cord protective threshold of serum memantine, an NMDA receptor antagonist, in a rabbit model of paraplegia

Purpose

To evaluate the threshold of serum memantine for prevention of spinal cord injury (SCI) in a rabbit paraplegic model.

Methods

Forty-two New Zealand white rabbits were divided into 7 groups. Preoperatively, oral memantine was given starting from 60 mg OD for 7 days in the initial group, then reducing the dose and/or duration to 60 mg OD for 5 days, 30 mg OD for 5 days, 30 mg OD for 3 days, 15 mg OD for 3 days, 30 mg single dose, and 60 mg single dose, in subsequent 6 groups. A paraplegic model was created by clamping both infrarenal aorta and inferior vena cava (IVC) for 45 min. Motor evoked potentials (MEPs), modified Tarlov score (0-5), serum memantine concentration, and histopathology of the spinal cord were evaluated.

Results

Half of all rabbits (21/42) showed spinal protection. Receiver operating characteristic (ROC) curve analysis showed serum level of 4.5 ng/ml as a cutoff value for spinal protection (sensitivity 86%, specificity 62%, area under the curve (AUC) 0.785, P = .002). Sixteen rabbits had serum level ≥ 4.5 ng/ml (group A), with 26 rabbits having < 4.5 ng/ml (group B). Further comparison was done between groups A and B. The mean modified Tarlov score at 6, 24, 48, and 72 h was 4.5 ± 0.9 and 2.4 ± 1.6, in groups A and B, respectively (P < .001). The modified Tarlov score showed positive correlation with serum memantine level (Spearman's rho = 0.618, P = .01). Results of MEP and histopathology were significantly better for group A.

Conclusions

We showed that memantine is protective against SCI at serum levels ≥ 4.5 ng/ml in a rabbit model; thus, it can be a potential adjunct for spinal protection during thoracic/thoracoabdominal aortic surgeries.

Kinematic and kinetic gait analysis to evaluate functional recovery in thoracic spinal cord injured rats

The recovery of walking function following spinal cord injury (SCI) is of major importance to patients and clinicians. In experimental SCI studies, a rat model is widely used to assess walking function, following thoracic spinal cord lesion. In an effort to provide a resource which investigators can refer to when seeking the most appropriate functional assay, the authors have compiled and categorized the behavioral assessments used to measure the deficits and recovery of the gait in thoracic SCI rats. These categories include kinematic and kinetic measurements. Within this categorization, we discuss the advantages and disadvantages of each type of measurement. The present review includes the type of outcome data that they produce, the technical difficulty and the time required to potentially train the animals to perform them, and the need for expensive or highly specialized equipment. The use of multiple kinematic and kinetic parameters is recommended to identify subtle deficits and processes involved in the compensatory mechanisms of walking function after experimental thoracic SCI in rats.

Nanofiber Scaffolds as Drug Delivery Systems to Bridge Spinal Cord Injury

The complex pathophysiology of spinal cord injury (SCI) may explain the current lack of an effective therapeutic approach for the regeneration of damaged neuronal cells and the recovery of motor functions. A primary mechanical injury in the spinal cord triggers a cascade of secondary events, which are involved in SCI instauration and progression. The aim of the present review is to provide an overview of the therapeutic neuro-protective and neuro-regenerative approaches, which involve the use of nanofibers as local drug delivery systems. Drugs released by nanofibers aim at preventing the cascade of secondary damage (neuro-protection), whereas nanofibrous structures are intended to re-establish neuronal connectivity through axonal sprouting (neuro-regeneration) promotion, in order to achieve a rapid functional recovery of spinal cord.