Figure 8

Expression of TGF-β1, its receptor and signalling proteins-Smads in the spinal cord and DRG. A: The expression of endogenous TGF-β1 mRNA was not detected by in situ hybridization at different time points after nerve injury. B: Endogenous TGF-β1 protein within the spinal cord was not found by Western Blot, however, intrathecal infusion of recombinant TGF-β1 for 14 days resulted in a stable level in both spinal cord ventral and dorsal horns. C: Expression of TGF-β type I receptor (TGF-βRI) mRNA was observed in the spinal cord and DRG. High magnification microscopic analysis revealed that positive signals (silver grains) for TGFβRI mRNA were located on both ventral horn motor neurons and DRG sensory neurons (identified based on the position, appearance and size of cells, encircled in blue), and on some glial cells in both dorsal and ventral horns that were heavily stained with thionine. D-E: Recombinant TGF-β1 induced phosphorylation of Smad 2/3 (pSmad2/3) (D) and up-regulated the total level of Smad 4 in the spinal cord. Tissue samples were collected 7 days post-injury and TGF-β1 infusion. Data are shown as means ± SEM. **p < 0.01, ***p < 0.001, TGF-β1 treated vs. saline treated in their respective region.