Abstract
Objective:
Spinal cord edema contributes to the pathophysiological mechanisms underlying spinal cord injury (SCI) and is associated with functional recovery after SCI. Early myelotomy may be a promising surgical intervention for reducing SCI-induced edema. However, it remains unclear whether myelotomy can reduce SCI-induced edema. In addition, aquaporin-4 (AQP4) and aquaporin-9 (AQP9) have important roles in the regulation of water homeostasis. Here, we aimed to determine the effects of myelotomy on AQP4 and AQP9 expression and spinal cord edema in a rat model of moderate SCI.
Methods:
Rats were randomly assigned to three groups: the sham control group (n=22) receiving laminectomy alone; the contusion group (n=44) receiving laminectomy plus contusion; and the myelotomy group (n=44) receiving laminectomy plus contusion followed by myelotomy at 24 h. Functional recovery was estimated by the open-field and inclined plane tests. Spinal cord edema was determined by measuring the water content. The expression of AQP4 and AQP9 was determined by western blot.
Results:
Compared with the contusion group, myelotomy significantly improved the Basso, Beattie and Bresnahan scores in the open-field test and resulted in a higher mean angle value in the incline plane test. Myelotomy significantly reduced SCI-induced edema at 4 and 6 days after SCI, which was accompanied by downregulation of AQP4 and AQP9 expression.
Conclusion:
Myelotomy improves locomotor function, reduces edema in rats with SCI and is associated with decreased expression of AQP4 and AQP9.
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Acknowledgements
This work was supported by funds (Special Funds Projects for Basic Scientific Research Business Expenses of Central Public Welfare Research Institutes in Chinese: No. 2012CZ-1, State Natural Science Foundation: No. 81272164, the Supporting Program of the ‘Twelve Five-year Plan’ for Sci& Tech Research of China: 2012BAI34B02).
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Hu, AM., Li, JJ., Sun, W. et al. Myelotomy reduces spinal cord edema and inhibits aquaporin-4 and aquaporin-9 expression in rats with spinal cord injury. Spinal Cord 53, 98–102 (2015). https://doi.org/10.1038/sc.2014.209
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DOI: https://doi.org/10.1038/sc.2014.209
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