Abstract presented at Society for Neuroscience Meeting, San Diego, October 2004.
Neurofilament subunit NF - H as a serum biomarker of neuronal damage and death following experimental traumatic brain injury.
K.J.Anderson1*; S.Scheff2; K.Miller2; K.Roberts2; G.Shaw3,4
1 Dept Physiol Sci, Univ Florida, Gainesville, FL, USA; 2 Anat. and Neurobiology, Univ Kentucky, Lexington, KY, USA; 3 Dept Neurosci, Univ Florida, Gainesville, FL, USA; 4 EnCor Biotechnology Inc., Alachua, FL, USA
Injured and dying neurons are expected to release their protein contents into the CSF and serum. We hypothesized that neurofilament NF-H, a major neuron-specific protein concentrated in axons, might be released from injured and dying neurons in amounts large enough to allow detection in serum. Accordingly, we developed an ELISA capture assay capable of detecting nanogram amounts of NF-H, and examined NF-H levels in sera of rats subjected to experimental traumatic brain injury (TBI), or appropriate controls. TBI animals were subjected to a variety of cortical contusion injuries using an IH impacting device, and blood samples were taken at defined times post injury. Control rats were sham operated or naive. NF-H was readily detectable in sera following TBI, while no signal was detectable in the sera of control animals. Serum NF-H was detected at 6 hours post injury, and serum levels rose to a peak at about 16 hrs post injury. A second somewhat larger peak was noted at 2 days post injury. NF-H levels then slowly decreased to baseline levels in the following several days. The results obtained are comparable to those we have recently obtained with rats given experimental spinal cord injuries, although the NF-H signal in TBI is about one order of magnitude lower. The cortex, the primary damage site for TBI, is not rich in large diameter NF-H rich axons, which are much more prevalent in the spinal cord. These findings do suggest, however, that the measurement of serum levels of NF-H may be a convenient method for assessing neuronal damage and death following brain injury.