Local inhibition of matrix metalloproteinases reduced M2 macrophage activity and impeded recovery in spinal cord transected rats after treatment with fibroblast growth factor-1 and nerve grafts

This study investigates how blocking the movement of macrophages, a type of immune cell, affects recovery in rats with spinal cord injuries treated with nerve grafts and a growth factor. The researchers found that inhibiting the migration of M2 macrophages, which are believed to help with tissue repair, reduced the benefits of the treatment. This suggests that the movement of these M2 macrophages is crucial for the treatment's success and needs to be considered when developing new spinal cord injury therapies.

• 1
  MMP-9, but not MMP-2, was upregulated in the graft area of rats treated with fibroblast growth factor-1 and peripheral nerve grafts, suggesting a role in the regenerative process.
• 2
  Local application of an MMP inhibitor reduced the ratio of arginase-1 (M2 macrophage subset)/inducible nitric oxide synthase-postive cells, indicating a decrease in M2 macrophage activity.
• 3
  Inhibition of MMPs at 8 weeks postoperation led to a loss of partial functional recovery and a decrease in brain-derived neurotrophic factor levels in the nerve graft.