The effect of chondroitinase ABC and photobiomodulation therapy on neuropathic pain after spinal cord injury in adult male rats

Abstract Introduction . The goal of the study was to test the effects of photobiomodulation therapy (PBMT) and intra-spinal injection of chondroitinase ABC (chABC) both alone and combined on pain induced by spinal cord injury (SCI) in rats. Material and methods : SCI was induced by compression using an aneurysm clip. PBMT used a 660 nm laser starting at 30 minutes after SCI and then daily for 2 week, and at the end of 1-week ChABC was injected into the spinal cord. Allodynia (mechanical and cold), hyperalgesia (mechanical and thermal) and functional recovery were measured. Molecular levels of IL6, BDNF, GDNF and Gad65 were evaluated. Results . Both ChABC, PBMT and the combination reduced allodynia and thermal hyperalgesia and improved functional recovery, but did not reduce mechanical hyperalgesia. Pain-related factors (BDNF and IL6) were decreased and anti-nociceptive factors (Gad65 and GDNF) were increased. Conclusion . Treatment of SCI by PBM is a non-invasive technique, and could be improved by ChABC injection to reduce neuropathic pain and improve movement.