A combination of a silicon implant, which releases a drug, and treadmill rehabilitation shows promise for treating complete spinal injuries in rats. The results, published in the open access journal Molecular Brain, suggest that the combination worked better than the drug alone.
The scientists were investigating the clinical applications of a semaphorin3A inhibitor to treat severed spinal cords in rats. Previous studies have shown similar inhibitors to be effective and they wanted to work out the best way of delivering the treatment, so that they could make the most of potential human trials.
Spinal cord injuries, where the spinal cord is damaged, disrupting the passage of signals around the body, primarily affect young adults. Car accidents are the most frequent cause, but falls and sports injuries are also common causes. There are currently no effective treatments, though surgery and rehabilitation therapy can help repair some damage.
The scientists from Keio University, Japan, investigated how well the treatment improved walking in adult rats with completely severed spinal cords. A silicon implant, which releases the Semaphorin 3A inhibitor slowly and continuously to the injury site, proved to be a highly effective delivery system. Some rats also received the treatment alongside repeated treadmill walking training, and this group showed the best recovery of all treatment conditions.
The researchers believe the reason is that while the drug helped general neural repair, the treadmill training targeted precise repair to the central pattern generators – centres in the spinal column that coordinate repetitive movements like walking. They hope that if these results are confirmed in humans, this might suggest effective new treatment methods for serious spinal injuries.
Rewiring of regenerated axons by combining treadmill training with semaphorin3A inhibition, Liang Zhang, Shinjiro Kaneko, Kaoru Kikuchi, Akihiko Sano, Miho Maeda, Akiyoshi Kishino, Shinsuke Shibata, Masahiko Mukaino, Yoshiaki Toyama, Meigen Liu, Toru Kimura, Hideyuki Okano and Masaya Nakamura, Molecular Brain 2014.