Effects of Electro-Acupuncture on IGF-I Expression in Spared Dorsal Root Ganglia and Associated Spinal Dorsal Horn in Cats Subjected to Adjacent Dorsal Root Ganglionectomies

The effects of electro-acupuncture (EA) on insulin-like growth factor-I (IGF-I) expression in the spared dorsal root ganglia (DRG) and associated spinal dorsal horns were explored in cats subjected to unilateral removal of L₁–L₅ and L₇–S₂ DRG, sparing the L₆ DRG. Immunohistochemistry revealed the presence of IGF-I immunoreactive products in the L₆ DRG neurons and some neurons and glial cells in the spinal cord. Western blot demonstrated that the level of IGF-I was significantly up-regulated both in the spared DRG and the dorsal horns of L₃ and L₆ cord segments at both 7 and 14 days post operation following EA. The present findings demonstrated the association between neuroplasticity and IGF-I expression, suggesting the possible role of IGF-I in EA promoted spinal cord plasticity.