Effect of electroacupuncture stimulation on apoptosis of nerve cells in a rat model of spinal cord contusion / 中国组织工程研究

ABSTRACT

BACKGROUND:Electroacupuncture has promoting effects on the functional recovery of the injured spinal cord, can decrease pain, and elevate postoperative effect after acute spinal cord contusion.OBJECTIVE:To observe the effect of electroacupuncture on apoptosis in the injured site after spinal cord contusion, and analyze its neuroprotective effects on neurological function in rats with spinal cord contusion. METHODS:A total of 66 adult female Sprague-Dawley rats were randomly divided into sham surgery group (n=20), spinal cord contusion group (n=20), electroacupuncture stimulation group (n=20) because six rats were excluded due to modeling failure and death. Before model establishment, at 1, 3 days, 1, 2, 3 and 4 weeks after model establishment, motor functions were evaluated by BBB score and the inclined plate test. At 3 days after model establishment, apoptosis of nerve cels could be detected in the site of injury in each experimental group using TUNEL assay. mRNA and protein expression of bax, bcl-2 and caspase-3 was detected surrounding the injury site using RT-PCR and western blot assay. Morphological changes in the site of injury could be observed using hematoxylin-eosin staining. The regeneration of nerve fibers was observed using HRP tracing. RESULTS AND CONCLUSION:(1) Motor function score was significantly increased at various time points in the 2nd week of treatment in the electroacupuncture stimulation group than in the spinal cord contusion group (P< 0.05). (2) Apoptotic index was significantly lower in the electroacupuncture stimulation group than in the spinal cord contusion group at 3 days after model establishment (P < 0.05). (3) mRNA and protein expression of bax and caspase-3 was significantly lower in the electroacupuncture stimulation group than in the spinal cord contusion group at 72 hours (P < 0.05); bcl-2 gene and protein expression was significantly higher (P < 0.05). (4) The number of HRP-positive nerve fibers was highest in the sham surgery group, folowed by electroacupuncture stimulation group, and lowest in the spinal cord contusion group at 4 weeks (P < 0.05). Results indicated that electroacupuncture plays a protective role on the spinal cord contusion by reducing apoptosis of nerve cels at the site of injury.