不同疗程电针对放射性脑损伤模型小鼠认知功能及海马神经元凋亡的影响

Effects of Different Courses of Electroacupuncture Intervention on Cognitive Function and Hippocampal Neuron Apoptosis in Radiation Brain Injury Model Mice

目的从海马区神经元凋亡的角度探讨不同疗程电针干预在放射性脑损伤小鼠认知功能的作用及相关机制。方法50只30日龄C57BL/6J小鼠随机分成对照组、放射性脑损伤模型组(8Gy)、电针组1(1周),电针组2(2周),电针组3(3周),每组10只。新物体认知方法检测各组小鼠认知功能,TUNEL方法检测凋亡细胞数,免疫组化方法检测各组小鼠海马区神经元凋亡相关指标caspase-3、凋亡诱导因子(AIF)平均光密度值。结果与对照组比较,模型组小鼠认知功能显著受损,表现为对新物体探索时间缩短(P<0.01,P<0.001),物体认知指数明显下降(P<0.05);而与模型组比较,电针1周、2周及3周组在90 min和24 h时探索新物体时间均不同程度增加(P<0.05,P<0.05,P<0.01)、(P<0.01,P<0.01,P<0.05),认知指数均不同程度提高(P<0.05,P<0.01,P<0.05)。TUNEL方法结果显示与对照组比较,模型组小鼠海马区神经元凋亡显著性增加(P<0.01);而与模型组比较,电针2周及3周组细胞凋亡数量明显减少(P<0.01,P<0.05);免疫组化结果显示与对照组比较,模型组小鼠海马区caspase-3阳性细胞数显著增加(P<0.01),而电针2、3周组阳性细胞数较模型组显著减少(P<0.01,P<0.05);与对照组比较,模型组AIF阳性细胞数显著增加(P<0.001),而电针各组较模型组均显著减少(P<0.001,P<0.01,P<0.01)。结论不同疗程电针干预可改善放射线照射对小鼠认知功能的损伤,可能与抑制海马区神经元凋亡有关,其中电针2周及3周效果最为显著。

Objective To explore the role of different courses of electroacupuncture in cognitive function and related mechanisms in mice with radiation brain injury from the perspective of neuronal apoptosis in the hippocampus.Methods Postnatal day 30 C57 BL/6 J mice were randomly divided into the control group,radioactive brain injury model groups(8 Gy),electroacupuncture group 1(EA 1),electroacupuncture group 2(EA 2)and electroacupuncture 3(EA 3),with 10 mice in each group.The cognitive function was evaluated by using novel object recognition test.The neuronal apoptosis and expression of caspase-3 and AIF in the hippocampus was observed by immunohistochemical analysis.Results Compared with the control group,the cognitive function of the model group was significantly impaired,as shown by the shortened exploration time for new objects(P<0.01,P<0.001)and a significantly decreased object cognitive index(P<0.05);Compared with the model group,the time of exploring new objects at 90 min and 24 h in EA1,EA 2 and EA 3 increased to varying degrees(P<0.05,P<0.05,P<0.01),(P<0.01,P<0.01,P<0.05),the cognitive index increased to varying degrees(P<0.05,P<0.01,P<0.05).The results of TUNEL method showed that compared with the control group,the apoptosis of neurons in the hippocampus of the model group increased significantly(P<0.01);Compared with the model group,the amount of apoptosis in EA 2 and EA 3 was significantly reduced(P<0.01,P<0.05);Immunohistochemical results showed that compared with the control group,the number of caspase-3 positive cells in the hippocampus of the model group was significantly increased(P<0.01),while the number of positive cells in EA 2 and EA 3 was significantly reduced(P<0.01,P<0.05);Compared with the control group,the number of AIF positive cells in the model group was significantly increased(P<0.001),while the electroacupuncture groups were significantly reduced compared to the model group(P<0.001,P<0.01,P<0.01).Conclusion Different courses of electroacupuncture intervention could improve the damage of cognitive function induced by radioactive exposure,and the effects may be related to the inhibition of neuronal apoptosis in hippocampus.The electroacupuncture had the most significant effects at 2 and 3 weeks.