Objective To observe the influence of different courses of electroacupuncture(EA)intervention on recognition memory and the proliferation and differentiation of hippocampal neural stem cells in mice with radiation-induced brain injury

so as to explore its mechanisms underlying improving radiation-induced brain injury.MethodsSeventy 30-day old C57BL/6 J mice were randomly divided into control

model and EA groups

and the latter two groups were further divided into 1 week(W)

2 W and 3 W subgroups(n=10 in the control group and each subgroup). The radiation-induced brain injury model was established by radiating the mouse'left head at a dose of 8 Gy for 10 min by using a radiation linear accelerator. EA(1. 5 V

2 Hz/10 Hz)was applied to"Baihui"(GV20)

"Fengfu"(GV14)and bilateral"Shenshu"(BL23)for 30 min

once daily for 1

2 and 3 weeks

respectively. The learning-cognition memory ability was detected by using novel object recognition test in an open test box to record the time for exploring a novel object(TN)and a familiar object and to calculate the recognition index(RI). The neural stem cells' proliferation and differentiation in the hippocampus tissues were evaluated by counting the number of bromodeoxyuridine(BrdU)-labeled cells

neuronal nuclei(NeuN)/BrdU-positive cells and BrdU/glia fibrillary acidic protein(GFAP)-positive cells under microscope after immunofluorescence stain.ResultsAfter modeling

the TN at 90 min and 24 h and RI of the model subgroup 3 W at 90 min and RI of the model subgroup 1

2 and 3 W at 24 h were significantly decreased in comparison with those of the control group(P<0. 01

P<0. 05). Moreover

the number of BrdU-positive cells in the model subgroup 1 W and 2 W

the BrdU/NeuN double-labeled cells in the 3 model subgroups and BrdU/GFAP double-labeled cells in the model subgroup 1 W and 3 W were significantly decreased(P<0. 01

P<0. 05). Following EA interventions

the TN in the 3 EA subgroups at both 90 min and 24 h

and RI of EA subgroup 3 W at 90 min and EA subgroup 2 W and 3 W at 24 h were considerably increased compared with those of the corresponding 3 model subgroups(P<0. 05

P<0. 01). The numbers of BrdU-positive cells as well as BrdU/NeuN and BrdU/GFAP double-labeled cells were significantly increased in the 3 EA subgroups(P<0. 05

P<0. 01

P<0. 001).ConclusionEA of GV20

GV14 and BL23 can improve the recognition memory ability of mice with radiation-induced brain injury

which may be related to its effect in promoting the proliferation and differentiation of stem cells in the hippocampus.