DO NEUROPROTECTIVE STRATEGIES PROTECT KEY TISSUES TO PRESERVE FUNCTION?
W. Dalton Dietrich, Ph.D. • Helen M. Bramlett, Ph.D. • Martin Oudega, Ph.D.
John R. Bethea, Ph.D. • Patrick M. Wood, Ph.D. • Mary B. Bunge, Ph.D.

In developing neuroprotective strategies, clarifying changes in the nervous system and identifying the specific tissues that need protection is important to the goal of preserving or restoring function. We also need to understand the immediate and delayed damage following injury. Drs. Bramlett and Dietrich examined the structural changes of the nervous system in brain injured animals one year after injury. They designed this study to help determine the course of progressive tissue loss following chronic central nervous system (CNS) injury. They found that both gray and white matter was affected. White matter damage may be the reason for some long term deficits experienced by patients with CNS injury.

In another study of spinally injured animals, researchers evaluated the effects of two well-known neuroprotective agents. Methylprednisolone (MP) is a drug commonly given to people within hours of their SCI. IL-10 is an anti-inflammatory drug tested in animals and shown to reduce tissue loss at the site of the lesion. Dr. Bunge and her colleagues evaluated the effects of MP and IL-10 administered alone or in combination. They looked at the volume of spared spinal tissue, nerve fiber preservation, and functional recovery. All combinations of the drugs produced similar results in increasing the volume of spared gray matter and preserving the number of axons. None of the treatment strategies, however, resulted in significant improvement in hindlimb function. Clearly, neuroprotective strategies to reduce gray matter damage are important, however, the lack of improvement in function seen in this study points to the importance of also developing treatments to limit white matter damage. This knowledge may lead to the design of new therapies to repair specific tissues that may be essential to recovery of function.