Grb2 Expression in Acute Spinal Cord Injury After Methylprednisolone Intrathecal Injection in Rats

Objective: This study aims to investigate the effect of methylprednisolone (MP) intrathecal injection on a rat model of acute spinal cord injury (ASCI). Methods: Allen's frame was used to establish a rat model of ASCI. MP and normal saline were intrathecally injected to Sprague-Dawley rats at 0, 3, 6, 8, 12, and 24 hours after ASCI, and injured spinal cord tissues were sterilely extracted after 24 hours of treatment. Isobaric tags for relative and absolute quantitation (iTRAQ) were coupled with 2-dimensional liquid chromatography tandem mass spectrometry to separate and identify differentially expressed proteins. Results: The expression of growth factor receptor- bound protein 2 (Grb2) was downregulated in the MP groups at 0 hours (iTRAQ ratio = 0.996), 3 hours (iTRAQ ratio = 0.737), 8 hours (iTRAQ ratio = 0.763), and 24 hours (iTRAQ ratio = 0.908) after injury compared with that in the control groups. No significant difference in Grb2 expression was observed between the control groups at 6 and 12 hours after ASCI. Conclusions: Standardized MP intrathecal injection after ASCI treatment reduces Grb2 activation in a rat ASCI model. Further studies should determine whether or not the same effect can be observed in human ASCIs.