Electroacupuncture induced spinal plasticity is linked to multiple gene expressions in dorsal root deafferented rats

The underlying mechanism for electroacupuncture (EA) associated functional improvement in patients suffering from spinal cord injury (SCI) is largely unknown. Collateral sprouting is one plausible factor, where the cord microenvironment may contribute greatly. The present study evaluated the effects of EA on collateral sprouting from spared dorsal root ganglion (DRG), sensory functional restorations, and differential gene expressions in spinal cord after partial DRG removal in the rat. Following EA, N1 waveform latencies for cortical somatosensory evoked potential significantly shortened. The densities of terminal sprouting from the spared DRG significantly increased on the EA versus the non-EA side. Microarray analysis revealed that several genes were upregulated on the acupunctured side at different time points; they were ciliary neurotrophic factor (CNTF) at 1 day postoperation (dpo), fibroblast growth factor (FGF)-1, insulin-like growth factor (IGF) 1 receptor, neuropeptide Y, and FGF-13 at 7 dpo, and CNTF and calcitonin gene-related polypeptide-alpha at 14 dpo, respectively. Meanwhile, five genes (CNTF, p75-like apoptosis-inducing death domain protein, IGF-1, transforming growth factor-beta 2, and FGF-4) were downregulated at 7 dpo. Furthermore, reverse transcriptase polymerase chain reaction results supported the gene chip analysis. It was concluded that the EA induced sensory functional restorations following partial DRG ganglionectomies could be brought about by intraspinal sprouting from the spared DRG, as well as multiple differential gene expressions in the spinal cord. The results could have clinical application in EA treatment of patients after spinal injury.