[Electroacupuncture reduces neuronal apoptosis in rats with spinal cord injury by regulating GSK-3β expression and its phosphorylation].

Objectives: To observe the effect of electroacupuncture (EA) stimulation of "Dazhui"(GV14) and "Mingmen" (GV4) of the Governor Vessel (GV) on the apoptosis of neurons in rats with spinal cord injury (SCI) by regulating the expression of glycogen synthase kinase-3β (GSK-3β) protein and its phosphorylation level, so as to reveal partial mechanism for the treatment of SCI with EA of GV.
Methods: A total of 45 male SD rats were randomly divided into sham-operation, model and EA groups, 15 rats in each group. The SCI model was established by using the modified Allen's percussion device. EA stimulation (2 Hz, 1 mA) was applied to GV14 and GV4 for 20 min, once daily for 28 days. Basso-Beattie-Bresnahan (BBB) locomotor rating scale was used to assess the rat's hind limb motor function at the 1 ^st , 7 ^th , 14 ^th , 21 ^th and 28 ^th day after modeling. H.E. staining was used to observe the histopathological changes of the injured spinal cord tissue. The expressions of GSK-3β and its phosphorylation at Ser9 site in the spinal cord were detected by immunohistochemistry and Western blot, respectively. The TUNEL staining was used to observe the apoptosis of neuron in the spinal cord.
Results: In comparison with the control group, the BBB scores from day 1 to day 28, and the expression and immunoactivity of p-GSK-3β were significantly decreased ( P <0.01), while the expression and immunoactivity of GSK-3β and the apoptosis index were significantly increased ( P <0.01) in the model group. In contrast to the model group, the EA group had a remarkable increase in the BBB score from day 7 to day 28, and the expression and immunoactivity of p-GSK-3β ( P <0.05, P <0.01), and an obvious decrease ( P <0.05, P <0.01) in the expression and immunoactivity of GSK-3β and the apoptosis index. H.E. staining showed that in the model group, the spinal cord structure of the SCI region was disorganized, with tissue cavity, blurred gray matter boundary, severe inflammatory infiltration, reduction of normal neurons, loss of cytoplasm, and nuclear contraction, which was relatively milder in the EA group.
Conclusions: EA at GV14 and GV4 can improve the symptoms of neurological function injury and reduce the apoptosis of neurons in rats with SCI, which may be achieved by regulating GSK-3β protein and its phosphorylation level.