不同疗程电针干预对放射线照射小鼠海马神经干细胞增殖分化的影响

Effect of different courses of electroacupuncture intervention on recognition memory and proliferation and differentiation of hippocampal neural stem cells in mice with radiation-in-duced brain injury

目的:观察不同疗程电针干预对放射性脑损伤小鼠海马区内源性神经干细胞增殖和分化的影响,探讨其改善放射性脑损伤的作用机制。方法:30日龄C57BL/6J小鼠随机分为对照组、模型1组、模型2组、模型3组、电针1组、电针2组和电针3组,每组10只。除对照组外,其他6组给予放射线照射(8 Gy)10 min制备放射性脑损伤模型,造模后3个电针组分别给予电针"百会""风府"和双侧"肾俞"1周、2周和3周。用新物体认知实验检测各组小鼠认知功能,免疫组织化学法检测海马区5-溴脱氧尿嘧啶(BrdU)的阳性表达,免疫荧光法检测海马区神经元核抗原(NeuN)及胶质纤维酸性蛋白(GFAP)的阳性表达。结果:与同时点对照组比较,各模型组小鼠在训练结束90 min和24 h时对新物体的探索时间均显著减少(P<0. 01);90 min时,模型3组小鼠的的认知指数显著下降(P<0. 05),24 h时,各模型组小鼠的认知指数均显著下降(P<0. 05);模型1组和模型2组小鼠海马区BrdU阳性细胞表达明显下降(P<0. 01);各模型组小鼠BrdU/NeuN双标阳性细胞数量均显著减少(P<0. 05),模型1组和模型3组BrdU/GFAP双标阳性细胞表达显著降低(P<0. 05)。与同时点模型组比较,各电针组在两个时间点对新物体的探索时间均明显增加(P<0. 05,P<0. 01);90 min时,电针3组的认知指数显著高于模型3组(P<0. 05),24 h时,电针2组和电针3组小鼠认知指数显著高于同时点模型组(P<0. 01);各电针组小鼠海马区BrdU阳性细胞、BrdU/NeuN和BrdU/GFAP双标阳性细胞均比同时点模型组显著增加(P<0. 05,P<0. 01,P<0. 001)。结论:不同疗程电针干预均可改善放射线照射小鼠的认知功能,可能与其促进小鼠海马区神经干细胞的增殖和分化有关。

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.