Tongdu Xingshen needling improves post-stroke cognitive impairment by regulating glycolysis in rats based on the HIF-1α/PDK1 pathway

To observe the effect of Tongdu Xingshen (unblocking the Governor Vessel and refreshing the spirit) needling on hypoxia-induced factor-1α/pyruvate dehydrogenase kinase 1 (HIF-1α/PDK1) pathway and hippocampal glycolysis level in rats with cerebral ischemia-reperfusion injury (CIRI), so as to explore its mechanisms underlying improvement of learning and memory ability.

SD rats were randomly divided into sham operation, model, acupuncture and acupuncture + inhibitor groups (n=12 in each group). The CIRI model was established by middle cerebral artery occlusion/reperfusion (MCAO/R). EA (1 Hz/20 Hz) was applied to “Shenting” (GV24) and “Baihui” (GV20) for 30 min, once daily for 14 consecutive days. In the acupuncture + inhibitor group, 2ME2 (5 mg/kg) was injected intraperitoneally 30 min before modeling. Learning and memory ability were evaluated by using open field test and new object recognition experiment. TTC staining was used to detect cerebral infarction volume. The pathological changes of hippocampus were observed by HE staining. The contents of lactic acid and ATP in hippocampal tissue were detected by colorimetric assay kit. The protein and mRNA expression levels of HIF-1α, PDK1, hexokinase 2 (HK2), phosphofructokinase 1 (PFK1) and pyruvate kinase M2 (PKM2) in hippocampal tissues on the ischemic side were detected by Western blot and qPCR, respectively.

Compared with the sham operation group, the rats in the model group had a significant decrease in the proportion of central distance, the number of crossing platform and the new object preference index (P<0.01), and a significant increase in percentage of cerebral infarction volume (P<0.01). The content of lactic acid in hippocampus, the protein and mRNA expression of HIF-1α, PDK1, HK2, PFK1 and PKM2 were increased significantly (P<0.01), while the content of ATP was decreased (P<0.01) in the model group compared with those in the sham operation group. Following the interventions, modeling induced increase and decrease of the indexes mentioned above were all reversed in the acupuncture group (P<0.01), and the therapeutic effects of acupuncture + inhibitor were better than those of acupuncture alone (P<0.01, P<0.05). H. E. staining showed disordered cell arrangement, abnormal morphology, and evident nuclear rupture and nuclear pyknosis in the hippocampus tissue in the model group, which was relatively milder in the two intervention groups.

Tongdu Xingshen needling can improve the learning and memory function of CIRI rats, which may be associated with its function in down-regulating the expression of HIF-1α/PDK1 signaling pathway, inhibiting anaerobic glycolysis in the hippocampus, reducing lactic acid accumulation and increasing ATP production.