Role of glutamate transporter 2 in electroacupuncture preconditioning-induced reduction of global cerebral ischemia-reperfusion injury in mice

Abstract

Objective To investigate the role of glutamate transporter 2 in electroacupuncture (EA) preconditioning-induced reduction of global cerebral ischemia-reperfusion (I/R) injury in mice.Methods Forty-eight adult male C57BL/6 mice,aged 12 weeks,weighing 18-23 g,were randomly assigned into 6 groups (n =8 each):I/R group,ceftriaxone sodium group (group CXT),normal saline group (group NS),EA preconditioning group,glutamate transporter 2 inhibitor dihydrokainate + EA group (group DHK + EA) and normal saline + EA group (group NS + EA).Ceftriaxone sodium 600 mg/kg was injected intraperitoneally once a day for 5 consecutive days in group CXT.Baihui acupiont (GV20) was electrically stimulated with 1 mA (frequency of sparse wave 2 Hz,frequency of dense wave 15 Hz,wave length 0.6 ms) for 30 min once a day for 5 days in groups EA,DHK+ EA and NS + EA.Dihydrokainate 200 μg/kg was injected via the lateral ventricle I h before ischemia in DHK + EA group.Global cerebral I/R was induced by occlusion of bilateral common carotid artery for 20 min followed by reperfusion at 24 h after preconditioning.Neurological function was assessed and scored at 24 h of reperfusion.The mice were then sacrificed and brains were removed and cut into sections which were stained with HE.The number of injured neurons in the CA 1 area in hippocampus was recorded under a light microscope.Results The neurological function scores were significantly higher and the number of injured neurons was smaller in CXT,NS + EA and EA groups than in I/R group (P ＜ 0.05),and there was no significant difference in the parameters mentioned above between NS and I/R groups (P ＞ 0.05).Compared with group EA,neurological function scores were significantly decreased and the number of injured neurons was increased in group DHK + EA (P ＜ 0.05),and no significant change was found in the parameters mentioned above in group NS + EA group (P ＞ 0.05).Conclusion EA preconditioning reduces global cerebral I/R injury through up-regulation of glutamate transporter 2 expression in mice. Key words: Excitatory amino acid transporter 2; Glutamic acid; Electroacupuncture; Ischemic preconditioning; Brain ischemia; Reperfusion injury