针刺对创伤性脑损伤大鼠神经损伤的影响

Effect of acupuncture intervention on neurological function,cerebral microglia activation and secondary nerve damage in traumatic brain injury rats

目的:通过观察小胶质细胞表达状态探讨针刺对创伤性颅脑损伤大鼠神经损伤的影响机制。方法:54只SD雄性大鼠按随机数字表分成正常组、模型组和针刺组,每组各18只。参照Feeney自由落体撞击法制备创伤性颅脑损伤大鼠模型。针刺组给予针刺"百会""水沟""风府"透"哑门"、双侧"合谷"穴,每天1次。治疗第3、7、14天后,分别进行改良大鼠神经功能缺损评分(mNSS),HE染色和免疫荧光标记法检测脑损伤的程度和小胶质细胞的表达量,采用酶联免疫法(ELISA)检测血清神经元特异性烯醇化酶(NSE)和勿动蛋白A(Nogo-A)含量的变化。结果:与正常组比较,模型组第1、3、7、14天mNSS显著升高(P<0.01);与模型组比较,针刺组第3、7、14天mNSS显著降低(P<0.05,P<0.01)。HE染色和免疫荧光标记结果可见,与正常组比较,模型组3个时点的组织结构持续破坏,神经元坏死,小胶质细胞大量活化(P<0.05);与模型组比较,针刺组3个时点组织结构破坏程度减轻,小胶质细胞活化减少(P<0.05)。与正常组比较,模型组3个时点血清NSE、Nogo-A含量显著升高(P<0.01);与模型组比较,针刺组3个时点血清NSE含量显著降低(P<0.01),第7、14天血清Nogo-A含量显著降低(P<0.01)。结论:针刺可能通过抑制小胶质细胞的表达及活化,继而抑制继发神经损害,促进神经功能恢复。

Objective To observe the effect of acupuncture on activities of microglia in traumatic brain injury(TBI)rats.Methods Fifty-four male SD rats were randomly and equally divided into normal control,model and acupuncture groups according to the random number table(n=18 rats in each group).The TBI model was established by using a free fall brain injury striking device after exposing the local cranial bone(to induce the left parietal cerebral contusion).Acupoints"Baihui"(GV20),"Shuigou"(GV26),"Fengfu"(GV16),"Yamen"(GV15)and bilateral"Hegu"(LII4)were stimulated intensively by twirling the filiform needles with force at a range of>360°and a frequency of 160-180 cycles/min for 10 sec in every acupoint,once every5 min during the 15 minutes’ needle retaining.The treatment was given once every day for successive 14 days.The rats of the normal and model groups were grabbed and fixed with the same procedure.The behavioral changes were tested using modified neurological severity score(mNSS).The histopathological changes of the injured cerebral cortex tissues were observed by using hematoxylin-eosin(H.E.)staining,and the fluorescence intensity of Iba-1(marker of microglia)positive products in the surrounding tissue of the cerebral focus was displayed by immunofluorescence staining,and the contents of neuron specific enolate(NSE)and neurite outgrowth inhibitor-A(Nogo-A)in serum(indicating a secondary nerve damage)were assayed by ELISA.Results The mNSS scores were significantly increased on day 1,3,7 and 14 in the model group in comparison with the normal group(P<0.01)and considerably decreased at the 4 time-points after acupuncture intervention relevant to the model group(P<0.05,P<0.01).H.E.staining showed that modeling induced pathological changes such as the excursion of cell nucleus,cellular swelling,vacuole-like change,neuron death,karyopyknosis dissolution,and proliferation of fibrous tissue were relatively milder in the acupuncture group.The average fluorescence intensity values of Iba-1-positive products,serum NSE and Nogo-A contents on day3,7 and 14 were significantly higher in the model group than in the normal group(P<0.05,P<0.01),and notably down-regulated in the acupuncture group than in the model group(P<0.05,P<0.01,except Nogo-A on day 3).Conclusion Acupuncture intervention may accelerate neurological function recovery in TBI rats,which is closely related to its effects in inhibiting the activation of microglia and secondary nerve damage.