Background: Spinal cord injury (SCI), often characterized by sensory-motor dysfunction, is a major debilitating
disorder of the central nervous system. As no useful treatment for post-SCI complications has been approved thus far,
finding novel treatments is of great importance.
Objective: Considering the promising effects of melatonin (MEL) against destructive mechanisms in other models of brain
damage, in the current study we evaluated its ameliorative effects on sensory-motor outcomes, inflammatory mediators,
histological changes and other post-SCI complications.
Methods: Rats, in SCI and MEL groups, underwent laminectomy followed by a severe compression injury by an aneurysm
clip. Then, intrathecal treatment with vehicle (5% dimethyl sulfoxide) or MEL was carried out post-injury. Acetone drop,
von Frey, inclined plane, and BBB tests as well as weight changes and auricle temperature, were used to evaluate the
neuropathic pain, motor function, and other post-SCI complications. The effects of MEL on the activity of MMP-2 and
MMP-9 were assessed using gelatin zymography method every week till day 28 post-SCI. Histopathological assessments
were performed on days 14, 21, and 28.
Results: MEL treatment resulted in decreased motor dysfunction, mechanical and cold allodynia, auricle temperature, and
also ameliorated weight loss. Moreover, MEL suppressed MMP-9 activity while increasing that of MMP-2 post-SCI indicating its anti-neuroinflammatory effects. Also, MEL significantly preserved white matter myelinated areas and the
number of sensory neurons post-SCI.
Conclusion: The results suggest MEL as a promising candidate for medical therapies with advantageous effects on
improving functional recovery through suppressing inflammatory mediators, and attenuating spinal tissue damages.