Effects of Governor Vessel electroacupuncture on chloridion homeostasis in the cortex of rats with limb spasm after cerebral ischemia-reperfusion

Abstract

To observe the effect of electroacupuncture (EA) stimulation of Governor Vessel on chloridion (Cl-) homeostasis and the expression of γ-aminobutyric acid (GABA) and Na+-K+-Cl- cotransporter 1 (NKCC1) in the cerebral cortex of cerebral ischemia-reperfusion injury (CIRI) model rats, so as to explore its mechanism underl-ying alleviating limb spasm after stroke. Forty-five male SD rats were randomly divided into normal, sham-operation, model, EA and baclofen groups, with 9 rats in each group. The CIRI model was established by occlusion of the middle cerebral artery and reperfusion. EA(100 Hz) was applied to "Dazhui" (GV14), "Jizhong"(GV6) and "Houhui" for 30 min. Rats of the baclofen group received gavage of baclofen solution (0.4 mg/kg, 1 mL/100 g), once daily for 7 consecutive days. Neurological deficit score was assessed according to Zea Longa's method. The muscular tone of quadriceps femoris of the limb was evaluated by modified Ashworth scale and electrophysiological recor-ding methods, separately. TTC staining was used to detect cerebral infarction volume, and the brain water content of rats in each group was determined by wet and dry weight method. The contents of Cl- and GABA in the cerebral cortex were detected by colorimetric method, and the expression levels of NKCC1 mRNA and protein in the cerebral cortex were detected by quantitative real-time PCR and Western blot, separately. No significant differences were found between the normal and sham-operation groups in all the indexes. Compared with the normal and sham-operation groups, the neurological deficit score, modified Ashworth muscle tone score, brain water content, cerebral infarct volu-me percent, Cl- content and expression levels of NKCC1 mRNA and protein were all evidently increased (P<0.01), and muscle tone of electrophyiological electromyogram (EMG) signal and GABA content were strikingly decreased (P<0.01) in the model group. Compared with the model group, both EA and baclofen groups had an obvious increase in EMG signal displayed muscle tone, and GABA content (P<0.05, P<0.01), and a marked decrease in the neurological deficit score, modified Ashworth score, brain water content, cerebral infarct percent, Cl- content and expression levels of NKCC1 mRNA and protein (P<0.05, P<0.01). EA stimulation of acupoints of the Governor Vessel can improve the degree of limb spasm and reduce the degree of cerebral edema and infarction in rats with stroke, which may be related to its functions in protecting Cl- homeostasis, up-regulating GABA concentration, and down-regulating the expression of NKCC1 protein and mRNA in the cerebral cortex.