Omega-3 fatty acid, curcumin protect an injured spinal cord

Researchers from the Department of Neurosurgery at the David Geffen School of Medicine and the Department of Integrative Biology and Physiology at UCLA have found that a diet enriched with docosahexaenoic acid (DHA), an omega-3 fatty acid, and curcumin, a component of the Indian spice turmeric, can protect the injured spinal cord and minimize the clinical and biochemical effects of spinal cord myelopathy in rats. This finding is fleshed out in the article "Dietary therapy to promote neuroprotection in chronic spinal cord injury. Laboratory investigation," by Langston Holly, M.D., and colleagues, published today online in the Journal of Neurosurgery: Spine. DHA reduces inflammation and provides structural material to plasma membranes. Curcumin produces strong anti-inflammatory and antioxidant effects. Both agents are safe to use and have been documented to have positive effects on the injured brain. Thus the researchers hypothesized that the combined effects of DHA and curcumin could protect the spinal cord from the cascade of cellular and related biological injuries that result from chronic cord injury.

Cervical spondylotic myelopathy is the most common disorder of the spine found in middle-aged patients. Neurological deficits associated with this disorder are related to a primary mechanical spinal injury that is followed by a secondary biological injury. Wear and tear on the spine, due to age or congenital narrowing of the spinal canal, leads to mechanical compression of the spinal cord. This cord compression in turn leads to biological cell injury or death and consequent neurological dysfunction. The primary mechanical injury can usually be corrected by surgery or other management strategies; to date, the secondary biological injury has been more difficult to treat.

The authors set out to develop a noninvasive way to promote neuroprotection from the biological injury that follows spinal cord compression in cervical spondylotic myelopathy. In the laboratory, the authors studied three groups of rats. To simulate cervical spondylotic myelopathy, the researchers placed an expandable polyvinyl alcohol sponge between two laminae of the spine in the animals. This produced delayed myelopathy. After the procedure, the first group of rats was fed a "Western diet" (a form of rat chow high in saturated fats and sugar), whereas the second group was fed a diet enriched with DHA and curcumin. A third group was given a standard rat diet and the animal's spines were left intact.

The animals' walking ability was examined before the procedure and repeatedly for several weeks following it. The researchers compared each group's walking behavior before and after the procedure and noted any differences between groups. Animals fed the Western diet demonstrated significant gait dysfunction as early as three weeks postoperatively, which continued throughout the six-week test period. Animals fed a diet enriched with DHA and curcumin displayed no significant difference in walking ability compared with preoperatively and demonstrated significantly better gait function six weeks after the procedure than animals fed the Western diet. Accompanying this paper, the authors provide two videos showing differences in gait function between these two groups.

The authors also examined the effects of diet after spinal injury on the molecular level. They measured levels of 4-hydroxynonenal (4-HNE), brain-derived neurotrophic factor (BDNF), and syntaxin-3 in the region of the rat spine that was compressed as well as in a region lower in the spine—the lumbar enlargement—where nerves controlling the lower limbs are attached to the spinal cord. The lumbar enlargement was included because cord injury can extend downward from the original site. Significantly higher levels of 4-HNE, an indication of severe cellular membrane damage, were found in both spinal sites in rats fed the Western diet. There was no significant difference between the levels of 4-HNE found in rats fed a diet enriched with DHA and curcumin and control rats with intact spines. Levels of BDNF and syntaxin-3 were significantly lower in both spinal sites in rats fed the Western diet. There were no significant differences in the levels of BDNF and syntaxin-3 between rats fed the diet enriched with DHA and curcumin and control rats. BDNF is a key factor involved in neural repair and promotes the transmission of information across synapses. Syntaxin-3 plays an important role in the release of neurotransmitters into the synapses.

This study shows that diet can play an important role in the response of the rat body to spinal injury. Rats fed a diet enriched with DHA and curcumin displayed significantly better walking ability than animals fed a "Western diet" high in saturated fats and sugar. In addition, there were significant differences in the levels of 4-HNE, BDNF, and syntaxin-3 between rats fed the Western diet and rats fed the DHA and curcumin–enriched diet. On the other hand, there were no significant differences in any of the parameters examined between rats fed the enriched diet and control rats with intact spines.

On the basis of their findings, the authors conclude: "DHA and curcumin can counteract the effects of chronic spinal cord compression through several molecular mechanisms, resulting in the preservation of neurological function."