Altered expression of Smad family members in injured motor neurons of rat

We examined changes in the expression of Smad family members, which transduce signals from TGF-β superfamily ligands, following hypoglossal nerve injury. RT–PCR and in situ hybridization revealed that Smad1, 2, 3 and 4 mRNAs were significantly up-regulated in injured side, whereas Smad8 mRNA was down-regulated. Immunohistochemistry and Western blotting analysis confirmed the alterations of Smad1, 2 and 4 in injured neurons. These results suggest that the Smad signaling may be important for nerve regeneration.