alpha-asarone and Reperfusion-Injury

Alpha-asarone, a major active component isolated from Acorus gramineus, can affect brain functions and behaviors by multiple mechanisms. However, the effect of alpha-asarone on cerebral ischemia-reperfusion (CIR) stroke has not been reported. The present study aimed to investigate the neuroprotective effect of alpha-asarone and the involved mechanisms against CIR stroke. Rats were subjected to middle cerebral occlusion (MCAO) for 2 h. Then the drug or drug-free vehicle was intravenously injected to corresponding groups. After reperfusion for 24 h, the infarct volume was evaluated by Triphenyl Tetrazolium Chloride (TTC) staining. The neurofunctional recovery and post-stroke epilepsy were evaluated. Nissl and Hematoxylin-Eosin (H&E) staining were used for histological observation. We investigated the protective mechanism of alpha-asarone against the stroke. The results showed that alpha-asarone exhibited a desirable neuroprotective effect, manifested as reducing infarct volume and post-stroke epilepsy and improving neurological function. Histological and flow cytometry analysis revealed that alpha-asarone treatment alleviated cell injury and apoptosis in vivo and in vitro. Furthermore, alpha-asarone decreased GFAP, Iba-1, and LC3II/LC3I expression and increased the expression of p62. These results suggested that alpha-asarone attenuated the CIR stroke injury via ameliorating glial activation and autophagy.

Topics: Allylbenzene Derivatives; Animals; Anisoles; Apoptosis; Autophagy; Brain Ischemia; Infarction, Middle Cerebral Artery; Neuroprotective Agents; Rats; Reperfusion; Reperfusion Injury; Stroke

Beta-asarone has significant pharmacological effects on the central nervous system. It can attenuate neuronal apoptosis, but its effects on the brain ischemia-reperfusion-induced autophagy have not been reported yet. Our study was a two-stage procedure: evaluation of β-asarone effects on the autophagy at first, and then analysis of the possible mechanism. The middle cerebral artery occlusion (MCAO) model was adopted to make the brain injure and Beclin 1 was used to evaluate the autophagy. We hypothesized that the mechanism might be related to c-Jun N-terminal kinases (JNK), phospho-JNK (p-JNK), Bcl-2 and Beclin 1. To test this hypothesis, we evaluated JNK, p-JNK, Bcl-2 and Beclin 1 levels with flow cytometry. Additionally, we divided the brain into three regions: ischemic region, ischemic penumbra, and normal region, and analyzed them respectively. We found, compared to both groups II (model control) and III (low dose), Beclin 1 levels in groups IV (medium dose) and V (high dose) were significantly decreased. Beclin 1, JNK and p-JNK levels in groups VII (β-asarone) and VIII (JNK inhibitor) were significantly decreased, but Bcl-2 levels were significantly increased. Additionally, Beclin 1, JNK, p-JNK and Bcl-2 levels among the three regions had no significant differences. We conclude that β-asarone can attenuate the autophagy in a dose-dependent manner. The mechanism is likely that β-asarone can decrease JNK and p-JNK levels at first, and then increase Bcl-2 level, finally interfere with the functions of Beclin 1 during the execution of autophagy. Additionally, β-asarone can attenuate autophagy in a widespread manner.

Topics: Allylbenzene Derivatives; Animals; Anisoles; Apoptosis; Apoptosis Regulatory Proteins; Autophagy; Beclin-1; Brain; Brain Ischemia; Infarction, Middle Cerebral Artery; JNK Mitogen-Activated Protein Kinases; Middle Cerebral Artery; Phosphopyruvate Hydratase; Phosphorylation; Proto-Oncogene Proteins c-bcl-2; Rats; Rats, Sprague-Dawley; Reperfusion Injury

To explore the effects of β-asarone from Acorus Tatarinowii Schott on autophagy in an ischemic stroke model of PC12 cells.. The ischemic stroke model of PC12 cells was made by OGD/R (2 h oxygen-glucose deprivation followed by 24 h reperfusion). Drug administration was started 1 h before OGD and last for 3 h. Then the cells were incubated in the drug-free and full culture medium under normoxic conditions for 24 h. After the treatments, Beclin-1, intracellular free calcium concentration ([Ca(2+)](i)) and mitochondrial membrane potential (MMP) were analyzed using flow cytometry. Cell viability was measured using MTT assay. Cell morphology was studied under inverted phase contrast microscope, and autophagosomes were observed under transmission electron microscope.. Pretreatment with β-asarone (20, 30, or 45 μg/mL) or the calcium channel antagonist nimodipine (10 μmol/L) significantly increased the cell viability and MMP, and decreased Beclin-1 expression and [Ca(2+)](i) in OGD/R-treated PC12 cells. Under inverted phase contrast microscope, pretreatment with β-asarone or nimodipine dramatically increase the number of cells and improved the cellular morphology. Autophagosomes were found in OGD/R-treated PC12 cells as well as in drug plus OGD/R-treated PC12 cells.. β-Asarone protects PC12 cells against OGD/R-induced injury partly due to attenuating Beclin-1-dependent autophagy caused by decreasing [Ca(2+)](i) and increasing MMP.

Topics: Acorus; Allylbenzene Derivatives; Animals; Anisoles; Apoptosis Regulatory Proteins; Autophagy; Beclin-1; Brain Ischemia; Calcium; Calcium Channel Blockers; Cell Survival; Glucose; Membrane Potential, Mitochondrial; Neuroprotective Agents; Nimodipine; Oxygen; PC12 Cells; Rats; Reperfusion Injury