Abstract: Objective To investigate the level of phosphorylated high-molecular-weight neurofilament (pNF-H) after spinal cord injury (SCI), and explore the relationship between pNF-H and severity of SCI. Methods 20 Sprague-Dawley rats were equally divided into control group (group A), mild SCI group (group B), moderate SCI group (group C) and severe SCI group (group D). The level of pNF-H in serum, BBB score and remaining area of white matter were obtained at different time points. Results The level of serum pNF-H in groups B, C and D arrived at peaks 12 hours and 3 days after SCI, and there was significant difference among them (P<0.05). Both BBB score and remaining area of white matter 14 days after SCI negatively correlated with the level of pNF-H 3 days after SCI (r=-0.987 and r=-0.978, respectively). Conclusion The pNF-H increases twice after SCI in rats, and may be associated with the severe of SCI, which can be considered as a biomarker.

Key words: spinal cord injury, neurofilament, molecular biological evaluation, rats