Can minor trauma cause asymptomatic cervical spinal cord compression leading to severe cervical spinal cord injury in rats?

The study aimed to determine whether asymptomatic rats with cervical spinal cord compression (CSCC) experience more severe cervical spinal cord injury (SCI) compared with rats without CSCC under the same degree of minor trauma. Four weeks after the polyvinyl alcohol-polyacrylamide hydrogel was implanted into the C5 vertebral canal, asymptomatic rats were selected based on locomotor function score. Mild cervical SCI was subsequently established based on CSCC. The motor function, morphology, neuron loss, myelin destruction, nerve cell apoptosis, microglia activation, and neuroinflammation were evaluated after SCI. Under the same injury conditions, rats in the CSCC group exhibited more severe motor dysfunction compared with those without CSCC. Similarly, asymptomatic CSCC rats showed significant damage to spinal cord tissue, neurons, and myelin. Finally, compared with rats without CSCC, asymptomatic CSCC rats experienced increased nerve cell apoptosis, microglial activation, and neuroinflammation following the same SCI. In asymptomatic CSCC rats, the same degree of minor trauma resulted in more severe cervical SCI compared with rats without CSCC. This was evidenced by increased nerve cell apoptosis, microglial activation, neuron death, myelin destruction, and a strong neuroinflammatory response, leading to severe motor dysfunction.