title: Nogo-A expression dynamically varies after spinal cord injury.
abstract: The mechanism involved in neural regeneration after spinal cord injury is unclear. The myelin-derived protein Nogo-A, which is specific to the central nervous system, has been identified to negatively affect the cytoskeleton and growth program of axotomized neurons. Studies have shown that Nogo-A exerts immediate and chronic inhibitory effects on neurite outgrowth. In vivo, inhibitors of Nogo-A have been shown to lead to a marked enhancement of regenerative axon extension. We established a spinal cord injury model in rats using a free-falling weight drop device to subsequently investigate Nogo-A expression. Nogo-A mRNA and protein expression and immunoreactivity were detected in spinal cord tissue using real-time quantitative PCR, immunohistochemistry and western blot analysis. At 24 hours after spinal cord injury, Nogo-A protein and mRNA expression was low in the injured group compared with control and sham-operated groups. The levels then continued to drop further and were at their lowest at 3 days, rapidly rose to a peak after 7 days, and then gradually declined again after 14 days. These changes were observed at both the mRNA and protein level. The transient decrease observed early after injury followed by high levels for a few days indicates Nogo-A expression is time dependent. This may contribute to the lack of regeneration in the central nervous system after spinal cord injury. The dynamic variation of Nogo-A should be taken into account in the treatment of spinal cord injury.
authors.affiliation: Wuxi Hospital of Traditional Chinese Medicine, Institute of Orthopedics and Traumatology of Nanjing University of Chinese Medicine, Wuxi, Jiangsu Province, China.
authors.forename: Jian-Wei
authors.initials: JW
authors.lastname: Wang
authors.affiliation: Wuxi Hospital of Traditional Chinese Medicine, Institute of Orthopedics and Traumatology of Nanjing University of Chinese Medicine, Wuxi, Jiangsu Province, China.
authors.forename: Jun-Feng
authors.initials: JF
authors.lastname: Yang
authors.affiliation: Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Ma
authors.affiliation: Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Hua
authors.affiliation: Wuxi Hospital of Traditional Chinese Medicine, Institute of Orthopedics and Traumatology of Nanjing University of Chinese Medicine, Wuxi, Jiangsu Province, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Guo
authors.affiliation: Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, China.
authors.forename: Xiao-Lin
authors.initials: XL
authors.lastname: Gu
authors.affiliation: Wuxi Hospital of Traditional Chinese Medicine, Institute of Orthopedics and Traumatology of Nanjing University of Chinese Medicine, Wuxi, Jiangsu Province, China.
authors.forename: Ya-Feng
authors.initials: YF
authors.lastname: Zhang
keywords: Nogo-A; axon growth; contusion; fluorescent quantitative PCR; immunohistochemistry; nerve regeneration; neural regeneration; spinal cord injury