Objective: To observe the effects of Xingnao Kaiqiao (regaining consciousness and opening orifices) acupuncture therapy on the expression of hypoxia-inducible factor 1α (HIF-1α) and Nod-like receptor protein 3 (NLRP3) in cerebral ischemia-reperfusion rats, and to explore the mechanism of acupuncture against cerebral ischemia-reperfusion injury.
Methods: Seventy-two male SD rats were randomly divided into a sham-operation group, a model group, an acupuncture group and a non-point acupuncture group, with 18 rats in each one. Using modified Longa thread embolization method, the rat model of acute focal cerebral ischemia was prepared; and after 2 h ischemia, the reperfusion was performed to prepared the model of cerebral ischemia-reperfusion. Immediately after reperfusion, Xingnao Kaiqiao acupuncture method was applied to bilateral "Neiguan" (PC 6) and "Shuigou" (GV 26) in the acupuncture group, while in the non-point acupuncture group, acupuncture was delivered at non-points and all of the needles were retained for 30 min in these two groups. The samples were collected 24 h after reperfusion in the rats of each group. Zea-Longa neurological deficit score was used to evaluate the degree of cerebral neurological impairment, TTC staining was adopted to observe the volume percentage of cerebral infarction, HE staining was provided to observe the morphological changes of brain, and Western blot was applied for detecting the expression of HIF-1α and NLRP3 proteins in the cerebral cortex on the right side.
Results: Compared with the sham-operation group, neurological deficit score and volume percentage of cerebral infarction were increased in the model group (P<0.01), and HIF-1α and NLRP3 protein expression was elevated (P<0.01). Compared with the model group, neurological deficit score and volume percentage of cerebral infarction were decreased (P<0.01), and HIF-1α and NLRP3 protein expression was lower (P<0.01) in the acupuncture group. There was no significant difference in above indexes in the non-point acupuncture group compared with the model group (P>0.05). Compared with the sham-operation group, the brain tissue of the rats in the model group and the non-point acupuncture group was loose and edema, and the nuclei were shriveled. The brain tissue morphology in the acupuncture group was similar to that of the sham-operation group.
Conclusion: Acupuncture can alleviate cerebral ischemia-reperfusion injury, and its mechanism may be related to the regulation of HIF-1α/NLRP3 signaling pathway to attenuate inflammatory response.
目的：观察“醒脑开窍”针法对脑缺血再灌注损伤大鼠缺氧诱导因子1α（HIF-1α）、Nod样受体蛋白3（NLRP3）表达的影响，探讨针刺抗脑缺血再灌注损伤的作用机制。方法：将72只雄性SD大鼠随机分为假手术组、模型组、针刺组及非穴位针刺组，每组18只。采用改良Longa线栓法建立急性局灶性脑缺血大鼠模型，缺血2 h后进行再灌注建立脑缺血再灌注大鼠模型。再灌注后即刻，针刺组采用“醒脑开窍”针法进行干预，穴取双侧“内关”及“水沟”，非穴位针刺组在非穴点行针刺干预，留针30 min。各组大鼠于再灌注后24 h取材。Zea-Longa神经功能缺损评分法对大鼠脑神经功能损伤程度进行评估，TTC染色法观察大鼠脑梗死体积百分比，HE染色法观察大鼠右侧大脑皮层组织形态，Western blot法检测大鼠右侧大脑皮层HIF-1α、NLRP3蛋白表达情况。结果：与假手术组比较，模型组大鼠神经功能缺损评分、脑梗死体积百分比升高（P<0.01），HIF-1α、NLRP3蛋白表达升高（P<0.01）。与模型组比较，针刺组大鼠神经功能缺损评分、脑梗死体积百分比降低（P<0.01），HIF-1α、NLRP3蛋白表达下降（P<0.01）；非穴位针刺组大鼠以上指标差异无统计学意义（P>0.05）。针刺组以上指标均优于非穴位针刺组（P<0.01）。与假手术组比较，模型组与非穴位针刺组大鼠脑组织疏松水肿，细胞核皱缩，针刺组大鼠脑组织形态趋近假手术组。结论：针刺干预可减轻脑缺血再灌注损伤，其作用机制可能与调控损伤侧大脑皮层HIF-1α、NLRP3表达从而减轻炎性反应有关。.
Keywords: Nod-like receptor protein 3 (NLRP3); acupuncture; cerebral ischemia-reperfusion injury; hypoxia-inducible factor 1α (HIF-1 alpha); inflammatory response.