[Effects of electro-acupuncture on neuronal apoptosis and associative function in rats with spinal cord injury]

To explore the effect of electro-acupuncture to improve the bladder function after acute spinal cord injury in rats and its possible mechanism.

Sixty healthy adult male SD rats of SPF grade, with body weight of 220 to 250 g, one week after feeding adaptation, were randomly divided into sham operation group, model group, electro-acupuncture group, electro-acupuncture control group with 15 rats in each group. Sham operation group underwent no stimulation, and the moderate damage model of spinal cord injury were made in other three groups according to modified Allens method. The model group were not treated, electro-acupuncture group were treated with electro-acupuncture on Zhibianxue and Shuidaoxue, and electro-acupuncture control group were treated with electro-acupuncture on 0.5 inch next to Zhibianxue and Shuidaoxue. The frequency of 2/100 Hz, current of 1 mA, stimulation time of 15 min, once a day, left and right alternately stimulate every time, for a total of 7 times. The changes of residual urine volume and urine output in rats at the 1st and the 7th days after operation were observed. And 7 d later, the rats were sacrificed and the injured spinal cord were taken out to observe the apoptosis, and to detect the changes of Bcl-2, Bax, Bad content.

After modeling,the rats of three groups showed different bladder dysfunction. In electro-acupuncture group and electro-acupuncture control group, the residual urine volume of the 7th day after operation was significant lower than the 1st day after operation (P < 0.001), and there was statistically significant difference on the 7th day after operation between two groups (P < 0.001). Compared with model group, the urine output of electro-acupuncture group and electro-acupuncture control group was significantly increased on the 7th day after operation, and there was sig- nificant difference between electro-acupuncture group and electro-acupuncture control group (P < 0.001). Electro-acupuncture can inhibit apoptosis of spinal cord neurons by TUNEL detection. Postoperative at 7 d, the rate of nerve cell apoptosis in electro -acupuncture group and electro-acupuncture control group was significant increased than model group (P < 0.01, P < 0.05), and there was significant difference between electro-acupuncture group and electro-acupuncture control group (P < 0.005). Compared with model group, the positive expression rate of Bax, Bad decreased (P < 0.01, P < 0.05), and Bcl-2 increased (P < 0.01) in electro-acupuncture group and electro-acupuncture control group,there was significant difference between electro-acupuncture group and electro-acupuncture control group (P < 0.01).

Electro-acupuncture can obviously promote the repair of acute spinal cord injury,its mechanism may be through increasing Bcl-2, inhibiting the expression of Bax, Bad, which inhibits the apoptosis of spinal cord neurons.