Evaluating Locomotor and Sensory Recovery in a Cervical Spinal Cord Injury Rat Model using Standardized methods.

Johana Bastidas¹, Megan R. Detloff², Linda Jones³, Marco Baptista³, Karim Fouad⁴, Wolfram Tetzlaff⁵, Taleen Hanania¹.

¹ Psychogenics, Paramus, New Jersey, US.
² Department of Neurobiology & Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, Pennsylvania, US,
³ Christopher & Dana Reeve Foundation, Short Hills, New Jersey, US.
⁴ University of Alberta, Department of Physical Therapy, Edmonton, Alberta, CA.
⁵ University of British Columbia, Vancouver, CA.

Spinal cord injury (SCI) is a debilitating condition that significantly impacts the quality of life. Incomplete tetraplegia, resulting from cervical spinal cord lesions, is the most common SCI type and often leads to varying degrees of paralysis, including in the upper limbs. For many individuals, regaining arm and hand function is essential for improving daily life. Reliable preclinical SCI models that assess forelimb function are crucial for developing effective therapeutics.

In collaboration with the Christopher and Dana Reeve Foundation and Drexel University, PsychoGenics validated a unilateral cervical SCI model in female Sprague Dawley rats. The model used a controlled lesion method (IH impactor) to create two lesion severities (150 and 200Kdyn). A laminectomy on the right C5 vertebra was followed by contusion SCI. Functional recovery was assessed over five weeks using a variety of locomotor tests, including the Martinez scale, Cylinder test, and horizontal ladder test. Skilled forelimb locomotion was measured using the Irvine, Beattie, and Bresnahan Forelimb Scale (IBB) and lever-pull tasks. Gait changes were analyzed using the Neurocube platform, and sensory responses to mechanical (VF test), cold (acetone), and heat (Hargreaves test) stimuli were evaluated.

Sham-lesioned animals showed minimal changes, while those with 150 and 200Kdyn lesions displayed significant deficits. Differences between SCI severities were most noticeable in the Martinez Open Field test and IBB score. Sensitivity to mechanical and cold stimuli increased in both hindlimbs, especially at five weeks post-injury.

This validated model offers a valuable platform for assessing cervical SCI and evaluating therapeutic interventions.