Expression of TGFβ2 but not TGFβ1 correlates with the deposition of scar tissue in the lesioned spinal cord

Transforming growth factor-βs (TGFβs) are implicated in fibrotic pathologies. TGFβ1 and -β2 expression is increased around the glial/fibrotic scar in the injured brain. Moreover, local injection of TGFβ antagonists into cerebral wounds reduces glial scarring. Here, we monitored expression of TGFβ1 and -β2 mRNA and protein in the spinal cord after transection of the dorsal funiculi. Levels of TGFβ1 mRNA were most elevated over the acute inflammatory phase, while TGFβ2 mRNA levels were raised locally about the wound, particularly in astrocytes and neovascular endothelial cells, over the subacute period of scarring. TGFβ protein production also increased after injury. Both TGFβ1 and TGFβ2 were found in hematogenous inflammatory cells, while TGFβ1 was also neuron-associated, and high levels of TGFβ2 were localized to multiple cell types in the wound, including reactive astrocytes, during the period of glial/collagen scar formation. The cellular localization and temporal pattern of expression of TGFβ after spinal cord injury suggest that TGFβ1 modulates the inflammatory and neuronal responses, while TGFβ2 regulates glial/collagen scarring.