Electroacupuncture ameliorates cerebral ischemia/reperfusion injury by suppressing autophagy via the SIRT1-FOXO1 signaling pathway.

Cerebral ischemia/reperfusion (CIR) injury occurs when blood flow is restored in the brain, causing secondary damage to the ischemic tissues. Previous studies have shown that electroacupuncture (EA) treatment contributes to brain protection against CIR injury through modulating autophagy. Studies indicated that SIRT1-FOXO1 plays a crucial role in regulating autophagy. Here we investigated the mechanisms underlying the neuroprotective effect of EA and its role in modulating autophagy via the SIRT1-FOXO1 signaling pathway in rats with CIR injury. EA pretreatment at "Baihui", "Quchi" and "Zusanli" acupoints (2/15Hz, 1mA, 30 min/day) was performed for 5 days before the rats were subjected to middle cerebral artery occlusion, and the results indicated that EA pretreatment substantially reduced the Longa score and infarct volume, increased the dendritic spine density and lessened autophagosomes in the peri-ischemic cortex of rats. Additionally, EA pretreatment also reduced the ratio of LC3-II/LC3-I, the levels of Ac-FOXO1 and Atg7, and the interaction of Ac-FOXO1 and Atg7, but increased the levels of p62, SIRT1, and FOXO1. The above effects were abrogated by the SIRT1 inhibitor EX527. Thus, we presume that EA pretreatment elicits a neuroprotective effect against CIR injury, potentially by suppressing autophagy via activating the SIRT1-FOXO1 signaling pathway.

[Electroacupuncture pretreatment alleviated cerebral ischemia-reperfusion injury via suppressing autophagy in cerebral cortex tissue in rats].

OBJECTIVE: To investigate the effect of electroacupuncture (EA) preconditioning on autophagy in cerebral cortex tissues of rats with cerebral ischemia-reperfusion injury (CIRI), so as to explore its mechanisms underlying improvement of CIRI. METHODS: Thirty-three male Sprague-Dawley rats were randomly divided into sham operation, model and EA groups (n=11 in each group). EA (2 Hz/15 Hz, 1 mA) was applied to "Baihui"(GV20), "Quchi" (LI11) and "Zusanli" (ST36) for 30 min, once daily for 5 days, followed by establishment of CIRI model by occlusion of the middle cerebral artery (MCAO) for 1.5 h and reperfusion for 24 h. The neurological deficit score was assessed in reference to Longa's methods, and the infarct volume assessed by 2,3,5-triphenyltetrazolium chloride staining. The density of dendrite spines of neurons in the ischemic cerebral cortex tissue was detected by Golgi's staining, the autophagosome observed by electron microscopy, and the expression levels of microtubule-associated protein 1 light chain 3 (LC3) and p62 (a selective autophagy substrate) were detected by Western blot. RESULTS: Compared with the sham operation group, the neurological deficit score and infarct volume were significantly increased (P<0.01), the number of autophagosomes and the ratio of LC3-Ⅱ/LC3-Ⅰ also significantly increased (P<0.01), while the expression level of p62 was notably decreased in the model group (P<0.01). Following the intervention and in comparison with the model group, the neurological deficit score and infarct volume were significantly reduced (P<0.01), the number of autophagosomes and the ratio of LC3-Ⅱ/LC3-Ⅰ obviously decreased (P<0.01), and the expression of p62 was significantly up-regulated in the EA group (P<0.01). CONCLUSION: EA pretreatment is effective in improving CIRI in rats, which may be realized through suppressing autophagy in the ischemic cerebral cortex tissue.

[Coal tar pitch smoke extract-induced pyroptosis in human bronchial epithelial cells].

OBJECTIVE: To explore whether coal tar pitch smoke extract (CTP) induced pyroptosis in human bronchial epithelial cells (BEAS-2B). METHODS: BEAS-2B cells were treated with different concentrations of CTP (1, 3 µg/ml) for 8h and 24 h, respectively. Lactic dehydrogenase (LDH) activity and interleukin-1 beta (IL-1ß) levels in the supernatants of cell culture media were measured with LDH activity or human IL-1ß ELISA kit, respectively. The activity of Caspase-1 was measured with Caspase-1 colorimetric assay kit. RESULTS: The activity of caspase-1 in 1 and 3 µg/ml CTP groups were (9.29 ± 0.30) and (8.67 ± 0.59) µmol/ml respectively which were both significantly increased compared to that (7.42 ± 0.59) µmol/ml in the control group (P < 0.05) after 8 h exposure, but there was no significant difference in the activity of LDH and levels of IL-1ß in the cell culture media among the CTP and control groups. 24 h after exposure, the activity of LDH in the CTP (1, 3 µg/ml) groups were (1323.03 ± 28.53) and (1148.45 ± 16.42) U/dl respectively which were significantly higher than that (1091.93 ± 26.64) U/dl in the control group (P < 0.05), and the levels of IL-1ß in the CTP (1 and 3 µg/ml) groups were (125.37 ± 25.00) pg/ml and (92.04 ± 19.09) pg/ml respectively which were significantly higher than that (46.20 ± 14.43) pg/ml in the control group (P < 0.05), but there was no significant difference in the activity of Caspase-1 among CTP and control groups (P < 0.05). CONCLUSION: CTP treatment induced early increase in caspase-1 activity followed by the increase in LDH activity and IL-1 levels, indicative of pyroptosis in human bronchial epithelial cells.