Effect of electro-acupuncture preconditioning on expression of protein kinase R-like endoplasmic reticulum kinase in hippocampus of mice following cerebral ischemia-reperfusion

Abstract

Objective To evaluate the effect of electro-acupuncture preconditioning on the expression of protein kinase R-like endoplasmic reticulum kinase(PERK)in the hippocampus of mice following cerebral ischemia-reperfusion(I/R). Methods A total of 120 healthy male C56BL/6 mice, aged 7 weeks, weighing 20-30 g, were divided into 3 groups(n=40 each)using a random number table method: sham operation group(group S), cerebral I/R group(group I/R)and electro-acupuncture preconditioning group(group EA). Cerebral I/R was induced by clamping bilateral common carotid arteries for 15 min followed by restoring cerebral blood flow in anesthetized mice.Dazhui and Baihui acupoints were stimulated with disperse-dense waves of 1 mA for 30 min once a day, lasting for 5 consecutive days, and cerebral I/R model was established at 24 h after the last stimulation in group EA.Animals were sacrificed at 24 and 48 h of reperfusion, brains were removed, and hippocampi were isolated for determination of apoptotic neurons in hippocampal CAl region(by TUNEL)and expression of PERK(by Western blot). Results Compared with group S, the neurological deficit score and the number of apoptotic neurons in hippocampal CAl region were significantly increased at each time point of reperfusion in I/R and EA groups(P<0.05). Compared with group I/R, the neurological deficit score and the number of apoptotic neurons in hippocampal CAl region were significantly decreased at each time point of reperfusion in group EA(P<0.05). Conclusion The mechanism by which electro-acupuncture preconditioning mitigates endoplasmic reticulum stress during cerebral I/R may be related to inhibiting PERK activity in mice. Key words: Electric stimulation therapy; Ischemic preconditioning; Reperfusion injury; Brain; Endoplasmic reticulum stress