Acupuncture mediated miR-34c-5p regulates the autophagy of hippocampal neurons in rats with cerebral ischemia/reperfusion injury

Abstract

To observe the effect of acupuncture on the expression of miR-34c-5p, autophagy-related proteins and apoptosis rate in hippocampus of rats with cerebral ischemia/reperfusion injury (CI/RI), so as to explore its mechanism in regulating autophagy in hippocampal neurons in CI/RI rats. SD rats were randomly divided into sham operation, model, medication and acupuncture groups, with 20 rats in each group. The rat model of CI/RI was established by occlusion of the middle cerebral artery. In the acupuncture group, "Dazhui" (GV14), "Baihui" (GV20) and "Shuigou" (GV26) were punctured with filiform needles and stimulated manually once every 15 min, for 30 min. The rats of the medication group were intraperito-neally injected with edaravone (5 mg/kg). The treatment was conducted once every 12 h for a total of 7 times. The neurological de-ficit score of all the rats were evaluated according to Garcia's methods, and TTC staining was employed to assess the cerebral ischemic area (percentage of cerebral infarct area, CIA). Transmission electron microscopy (TEM) was used to observe the ultrastructural changes of hippocampal neurons. The expression of hippocampal miR-34c-5p was measured by real-time PCR, and the protein expressions of hippocampal LC3B, Beclin1 and p62 were measured by Western blot. The apoptosis rate of ischemic brain tissue was observed by TUNEL staining. Compared with the sham operation group, the neurological deficit score, the expressions of miR-34c-5p, Beclin1, p62 and LC3B-Ⅱ/LC3B-Ⅰ were significantly decreased (P<0.01, P<0.05), and the CIA and the apoptosis rate significantly increased (P<0.01) in the model group. Compared with the model group, the neurological deficit scores, the expressions of miR-34c-5p, Beclin1, p62 and LC3B-Ⅱ/LC3B-Ⅰ were significantly increased (P<0.01, P<0.05), and the CIA and the apoptosis rate significantly decreased (P<0.01) in the medication and acupuncture groups. Compared with the medication group, the expression of miR-34c-5p was significantly increased (P<0.01). The results of electron microscope showed that the neurons in the acupuncture and medication groups were less damaged than those in the model group, the cells showed mild edema, and the structures were relatively complete. Some normal organelles could be seen, and autophagy bodies, autophagy lysosomes and their encapsulated organelles could still be observed. Acupuncture can improve the neurological deficit and reduce the area of cerebral infarction in CI/RI rats, which is closely with its effect in promoting hippocampal neuronal autophagy and anti-apoptosis via up-regulating the expression of miR-34c-5p.