Transgenic mice with high endogenous omega-3 fatty acids are protected from spinal cord injury

Omega-3 polyunsaturated fatty acids have been shown to have therapeutic potential in a variety of neurological disorders, including acute traumatic injury of the spinal cord. We addressed the question whether the neuroprotective effect of these compounds after spinal cord injury could also be seen when their level is raised in tissues prophylactically, prior to injury. In this study we used transgenic fat-1 mice to examine whether enriching spinal cord tissue in endogenous omega-3 polyunsaturated fatty acids has an effect on the outcome after compression spinal cord injury. The results demonstrate that after thoracic compression spinal cord injury, fat-1 mice display better locomotor recovery compared with the wild-type mice on a high omega-6 diet (high omega-6 polyunsaturated fatty acids in tissues), and wild-type mice on a normal diet (controls). This is associated with a significant increase in neuronal and oligodendrocyte survival and a decrease in non-phosphorylated neurofilament loss. The protection from spinal cord injury in fat-1 mice was also correlated with a reduction in microglia/macrophage activation and in pro-inflammatory mediators. In vitro experiments in dorsal root ganglia primary sensory neurons further demonstrated that a fat-1 tissue background confers robust neuroprotection against a combined mechanical stretch and hypoxic injury. In conclusion, our studies support the hypothesis that a raised omega-3 polyunsaturated fatty acid level and an altered tissue omega-6/omega-3 ratio prior to injury leads to a much improved outcome after spinal cord injury.