针刺调控CIRI大鼠缺血侧海马组织差异表达circRNAs的功能研究

Research on function of acupuncture regulating differential expression of circRNAs in hippocampus of CIRI rats

目的:探讨针刺对脑缺血再灌注损伤(CIRI)大鼠脑组织的保护作用,观察针刺对CIRI大鼠缺血侧海马组织环状RNAs(circRNAs)差异表达的影响,并对其进行基因本体(GO)分析。方法:6~8周龄SD大鼠54只,运用随机数字法随机分为造模组和假手术组(sham组),造模成功后再随机分为模型组(model组)和针刺组(AC组),每组18只。采用改良Longa线栓法制备大脑中动脉闭塞再灌注(MCAO/R)模型,激光散斑成像仪监测造模前、MCAO手术后及再灌注后脑血流量,假手术组只剥离血管,不插入线栓;干预期间模型组和假手术组只捆绑不针刺,针刺组捆绑+针刺。采用改良加西亚(Garcia)评分法对神经功能进行评定,TTC染色法检测脑梗死面积,Western blot法检测神经元核抗原(NeuN)的表达,尼氏染色法观察缺血侧海马组织神经元损伤程度,基因芯片微阵列分析筛选出缺血侧海马组织差异表达的circRNAs,并对模型组/假手术组、针刺组/模型组共同差异表达circRNAs的来源基因进行GO分析。结果:与假手术组比较,模型组大鼠脑梗死面积比显著升高(P<0.01),Garcia神经功能评分、NeuN表达量和海马CA1区尼氏染色阳性细胞数显著降低(P<0.05或P<0.01);与模型组比较,针刺组脑梗死面积比显著降低(P<0.01),神经功能评分、NeuN表达量和尼氏染色阳性细胞数显著升高(P<0.05或P<0.01)。芯片筛选结果显示,与假手术组比较,模型组上调的circRNAs个数为288,下调个数为315;与模型组比较,针刺组上调的差异表达circRNAs个数为33,下调个数为18(FC>1.25,P<0.05);其中模型组/假手术组、针刺组/模型组共同差异表达的circRNAs个数为23个;GO分析显示共同差异表达circRNAs的来源基因功能涉及神经系统发育,神经元的产生、发育、分化及投射,头部、大脑及海马的发育,突触的形成、发育、延伸及运输等。结论:CIRI大鼠缺血侧海马组织circRNAs在造模后及针刺干预后均存在差异表达。针刺能显著改善CIRI大鼠的神经功能和脑梗死面积,减轻海马组织神经元损伤,其机制可能与针刺调控缺血侧海马组织多种circRNAs的差异表达及激发其促进神经元发育分化、抗神经损伤等功能有关。

AIM: To explore the protective effect of acupuncture on brain tissue of rats with cerebral ischemia reperfusion injury(CIRI), observe the effect of acupuncture on the differential expression of circular RNA(circRNA) in the hippocampus of the ischemic side of CIRI rats, and carry out gene ontology(GO) analysis on it. METHODS: Fifty four 6~8 week old SD rats were randomly divided into modeling group and sham operation group(sham group). CIRI rats were randomly divided into model group(model group) and acupuncture group(AC group) with 18 rats in each group. Establishment of middle cerebral artery occlusion reperfusion(MCAO/R) model by using Longa monofilament method. The cerebral blood flow was monitored by laser speckle imager. In the sham operation group, only the blood vessels were stripped without inserting thread plugs. The acupuncture group was bound+acupuncture every 12 h, 30 minutes for 7times, during which twirling manipulation was performed. The nerve function was evaluated by the modified Garcia scoring method. Cerebral infarction area was measured by TTC staining. Detection of the expression of neuronal nuclear antigen(NeuN) by Western blot. Observation of neuronal damage in ischemic hippocampus by Nissl staining. Gene chip microarray analysis was used to screen out the circRNA differentially expressed in the hippocampus of ischemic side, and GO analysis was performed on the source genes of common differentially expressed circRNA in model group vs sham group and AC group vs model group. RESULTS: Before intervention, compared with the sham group, the Garcia neural function score in the modeling group was significantly lower(P<0. 01). After intervention, compared with the sham group, the score of the Model group decreased significantly(P<0. 01). Compared with the model group, the score of AC group increased significantly(P<0. 01). Compared with before intervention, the score of AC group increased significantly after intervention(P<0. 01). Compared with the sham group, the area ratio of cerebral infarction in the model group was significantly increased(P<0. 01), the expression of NeuN was significantly decreased(P<0. 01), and the number of Nielsen staining positive cells in hippocampal CA1 neurons in the ischemic side was significantly decreased(P<0. 05). Compared with the model group, the area ratio of cerebral infarction in the AC group was significantly reduced(P<0. 01), the expression of NeuN was significantly increased(P<0. 05), and the number of neurons with positive Nissl staining was significantly increased(P<0. 05). The results of circRNA chip screening showed that, compared with the sham group, the number of up regulated circRNA in the model group was 288, and the number of down regulated circRNA was 315. Compared with the model group, the number of differential expression circRNA up-regulated and down-regulated in the AC group was 33and 18 respectively(FC>1. 25, P<0. 05). The number of common differential expression circRNA in model group vs sham group and AC group vs model group is 23. GO analysis showed that the source genes with common differential expression of circRNA may regulate cerebral ischemia-reperfusion injury by participating in the development of nervous system, the generation, development, differentiation and projection of neurons, the development of head, brain and hippocampus, and the formation, development, extension and transportation of synapses. CONCLUSION: Acupuncture improves the neurological function score and cerebral infarction area ratio of CIRI rats, and reduce neuronal damage in the hippocampus. The mechanism may be related to acupuncture regulating the differential expression of multiple circRNA in the ischemic hippocampus.