Effect of electroacupuncture at Ganshu (BL 18) and Shenshu (BL 23) on the expression of EphB2 protein in cortex around cerebral infracted area of rat

Abstract

To observe the effect of electroacupuncture (EA) on the expression of erythropoie-tin-producing hepatocyte receptor B2 (EphB2) in the cortex around the infracted area of middle cerebral artery occlusion (MCAO) rats at different timing, and to reveal the possible mechanism of acupuncture in the treatment of cerebral ischemia. A total of 180 male Sprague-Dawley (SD) rats were randomly divided into a sham operation group, a model group, an acupoint group and a non-acupoint group, with 45 rats in each group. Rats in each group were further divided into three subgroups: postoperative 3 d, postoperative 14 d and postoperative 21 d groups, with 15 rats in each subgroup. The MCAO model was made by the modified occlusion method. The neurological function score, 2,3,5-triphenyl tetrazolium chloride (TTC) staining, immunohistochemistry assay, immunofluorescence double labeling method and Western blot were used to detect the corresponding indicators. The neurological impairment of rats was most obvious at postoperative 3 d, and then gradually improved with time, which was more significant in the acupoint group (P<0.05). The change of infarcted volume was consistent with the neurological function impairment. The number of EphB2 positive cells (EphB2+) around the infarcted area was decreased significantly at postoperative 3 d, and then gradually improved with time, which returned to the same level as that in the sham operation group at postoperative 21 d. The increase was most significant in the acupoint group (P<0.05), and the positive cell number was higher than that in the sham operation group (P<0.01). Western blot and immunohistochemistry results were basically consistent. Immunofluorescence displayed that EphB2+ and postsynaptic density-95 positive (PSD-95+) were co-expressed, after the MCAO operation, in the cortical neuron around the infracted area, and the number of co-expressing cells was increased gradually with time, which was most significant in the acupoint group (P<0.05). Electroacupuncture at Ganshu (BL 18) and Shenshu (BL 23) can significantly improve the neurological function and cerebral infarcted volume ratio of MCAO rats, which may be related to the activation of EphB2 expression in cortex around the infracted area and the promotion of synaptic remodeling.