Effects of lipopolysaccharide-induced inflammation on expression of growth-associated genes by corticospinal neurons

This study explores whether inflammation can promote nerve regeneration in corticospinal neurons, which usually don't regenerate well after spinal cord injury. The researchers applied lipopolysaccharide (LPS), a substance that causes inflammation, to the motor cortex of rats to see if it would stimulate these neurons to express genes associated with growth. The application of LPS induced inflammation in the motor cortex, leading to increased expression of certain growth-associated genes like c-Jun, SCG10, and GAP-43 in corticospinal neurons. However, it had limited effects on the expression of ATF3 in neurons, although glial cells in the subcortical white matter did show increased ATF3 expression. Despite the increased expression of growth-associated genes, the inflammation caused by LPS was not enough to promote the regeneration of the corticospinal tract after spinal cord injury. The corticospinal axons did not grow into or beyond the lesion site.

• 1
  Application of LPS induced a gradient of inflammation throughout the motor cortex.
• 2
  LPS promoted increased expression of c-Jun and SCG10 for up to 2 weeks, and GAP-43 upregulation for 3 days by many corticospinal neurons.
• 3
  LPS did not promote sprouting of anterogradely labelled corticospinal axons, which did not grow into or beyond a cervical lesion site.