Delayed Exercise is Ineffective at Reversing Aberrant Nociceptive Afferent Plasticity or Neuropathic Pain after Spinal Cord Injury in Rats

Neurorehabil Neural Repair, 2016 · DOI: 10.1177/1545968315619698 · Published: August 1, 2016

Spinal Cord Injury Pain Management Rehabilitation

Simple Explanation

This study investigates whether delayed exercise intervention, initiated after pain onset, can alleviate spinal cord injury (SCI)-induced pain in rats. The findings suggest that exercise therapy started at early stages of pain is ineffective and may even induce pain in previously pain-free rats. The data indicate a critical therapeutic window where exercise is most beneficial for retaining normal sensation after SCI, closing before 14 days post-injury.

Study Duration

56 dpi

Participants

162 adult, female Sprague-Dawley rats

Evidence Level

Not specified

Key Findings

1
Exercise therapy initiated at early stages of allodynia is ineffective at attenuating neuropathic pain.
2
Exercise can induce allodynia and aberrant afferent plasticity in previously pain-free rats.
3
There is a critical therapeutic window when exercise therapy may be effective at treating SCI-induced allodynia.

Research Summary

The study determined if delaying exercise intervention until pain is detected would similarly ameliorate established SCI-induced pain. The results show that delaying exercise until allodynia develops or is more fully established neither reversed or attenuated allodynic behavior nor aberrant changes in the topographic distribution of nociceptive afferents in the dorsal horn. These data, combined with our previous results suggest that there is a critical therapeutic window when exercise therapy may be effective at treating SCI-induced allodynia and that there are post-injury periods when exercise can be deleterious.

Practical Implications

Timing of Intervention

Exercise therapy should be initiated within a specific therapeutic window post-SCI to be effective, likely before 14 days.

Potential Harm of Delayed Exercise

Delaying exercise until after allodynia is established may not only be ineffective but could also worsen the condition or induce pain in previously unaffected individuals.

Personalized Medicine

Individual injury situations may require a unique combination of intensity or duration of exercise in order to see beneficial anti-allodynic effects.

Study Limitations

1
The study used a rat model, and results may not directly translate to humans.
2
The specific mechanisms underlying exercise-induced afferent plasticity are not fully elucidated.
3
The optimal exercise parameters (duration, intensity, frequency) for reducing neuropathic pain require further investigation.

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