Effects of Electro-acupuncture on PDGF Expression in Spared Dorsal Root Ganglion and Associated Dorsal Horn Subjected to Partial Dorsal Root Ganglionectomy in Cats

The effects of electro-acupuncture (EA) on the expression of platelet derived growth factor (PDGF) in spared dorsal root ganglion (DRG) and associated dorsal horns were evaluated in cats subjected to bilateral removal of L₁–L₅ and L₇–S₂ DRG, while sparing L₆ DRG and were demonstrated using Immunohistochemistry, Western blot and RT-PCR techniques. On the acupunctured side, there was a significant increase in the total number of PDGF positive neurons. Large neurons of the L₆ DRG at 7 days post operation (dpo), and small to medium-sized neurons at 14 dpo, as well as in the lamina II of the L₆ spinal cord at 14 dpo was observed. The expression of PDGF protein increased significantly in the L₆ DRG at 7 and 14 dpo and in the dorsal horn of the L₆ spinal cord at 14 dpo while the upregulation of PDGF mRNA was seen at 3 dpo in the L₆ DRG and the dorsal horn of the L₃ and L₆ spinal cord. These findings demonstrate that intrinsic PDGF has been upregulated in cats subjected to partial dorsal root ganglionectomy following EA, indicating endogenous PDGF is involved in promoting spinal plasticity following EA.