Electro-acupuncture Reduces Neuronal Apoptosis Linked to Bax and Bcl-2 Expression in the Spinal Cords of Cats Subjected to Partial Dorsal Root Ganglionectomy

While electro-acupuncture (EA) has been well known to contribute towards neuroplasticity occurring in both the central and the peripheral nervous system after injury, the underlying mechanism remains largely unknown. This study evaluated the effects and the possible mechanism of EA on neuronal apoptosis in the spinal cords of cats subjected to the removal of L₁–L₅ and L₇–S₂ dorsal root ganglion, sparing the L₆ dorsal root ganglion. EA treatment decreased the number of TUNEL-positive apoptotic cells in lamina II of the L₃ and L₆ cord segments at 7 and 14 days post operation (dpo). This EA-mediated neuroprotection is associated with a decrease in the number of Bax immunoreactive neurons and an increase in the number of Bcl-2 immunoreactive neurons. Furthermore, Western blot and RT-PCR analysis revealed a significant downregulation of Bax protein and its mRNA, but an upregulation of Bcl-2 in the dorsal horn of L₃ and L₆ cords at both 7 and 14 dpo. The present findings suggest that EA could inhibit neuronal apoptosis in dorsal root deafferentated cat spinal cords, possibly by Bax downregulation and Bcl-2 upregulation. Wei Zhao and Qi Zhao contributed equally to this work.