Melastoma dodecandrum lour. Protects against cerebral ischemia-reperfusion injury by ameliorating oxidative stress and endoplasmic reticulum stress.
Melastoma dodecandrum Lour. (MD), a traditional Chinese medicine used by the She ethnic group, has been used to treat cerebral ischemia-reperfusion (CIR) injury due to its efficacy in promoting blood circulation and removing blood stasiss; however, the therapeutic effects and mechanisms of MD in treating CIR injury remain unclear.
To investigate the protective effects of MD on CIR injury, in addition to its impact on oxidative stress, endoplasmic reticulum (ER) stress, and cell apoptosis.
The research was conducted using both cell experiments and animal experiments. The CCK-8 method, immunofluorescence staining, and flow cytometry were used to analyze the effects of MD-containing serum on oxygen-glucose deprivation/reperfusion (OGD/R)-induced PC12 cell viability, reactive oxygen species (ROS) clearance, anti-inflammatory, neuroprotection and inhibition of apoptosis. Furthermore, 2,3,5-Triphenyl tetrazolium chloride staining, hematoxylin and eosin staining, Nissl staining, and immunohistochemistry were used to detect infarct size, pathological changes, Nissl corpuscula and neuronal protein expression in middle cerebral artery occlusion (MCAO) rats. Polymerase chain reaction and Western Blotting were conducted in cell and animal experiments to detect the expression levels of ER stress-related genes and proteins.
The MD extract enhanced the viability of PC12 cells under OGD/R modeling, reduced ROS and IL-6 levels, increased MBP levels, and inhibited cell apoptosis. Furthermore, MD improved the infarct area in MCAO rats, increased the number of Nissl bodies, and regulated neuronal protein levels including Microtubule-Associated Protein 2 (MAP-2), Myelin Basic Protein (MBP), Glial Fibrillary Acidic Protein (GFAP), and Neurofilament 200 (NF200). Additionally, MD could regulate the expression levels of oxidative stress proteins malondialdehyde (MDA), nitric oxide (NO), superoxide dismutase (SOD), and catalase (CAT). Both cell and animal experiments demonstrated that MD could inhibit ER stress-related proteins (GRP78, ATF4, ATF6, CHOP) and reduce cell apoptosis.
This study confirmed that the therapeutic mechanism of the MD extract on CIR injury was via the inhibition of oxidative stress and the ER stress pathway, in addition to the inhibition of apoptosis.
Liu S
，Zhang X
，Lin B
，Mao J
，Zhan J
，Li Y
，Zhou J
，Wang N
，Qiu W
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Geraniin Protects against Cerebral Ischemia/Reperfusion Injury by Suppressing Oxidative Stress and Neuronal Apoptosis via Regulation of the Nrf2/HO-1 Pathway.
Geraniin, a polyphenol isolated from Phyllanthus amarus, possesses extensive biological and pharmaceutical activities. In this study, we investigated the protective effect against cerebral ischemia/reperfusion (I/R) injury of geraniin and explored its potential mechanism. Middle cerebral artery occlusion/reperfusion (MCAO/R) was used to simulate cerebral I/R injury in vivo, and oxygen-glucose deprivation/reoxygenation (OGD/R) was applied to establish an in vitro model of cerebral I/R injury. In this study, we performed TTC and HE staining and adopted a neurological score method to evaluate the neuroprotective effect of geraniin in vivo and used the CCK-8 assay to assess this effect in vitro. Indices of reactive oxidation capacity were measured in vivo and in vitro to verify the antioxidant capacity of geraniin. TUNEL staining and flow cytometry were applied to measure the apoptosis rate, and Western blotting was performed to assess the expression of apoptosis-related proteins. Finally, the expression of Nrf2 and HO-1 was evaluated in vivo and in vitro by Western blotting. Geraniin significantly reduced the infarct volume, decreased neurological deficit scores, alleviated pathological changes in neurons, and increased the cell survival rate. Geraniin increased the activity of superoxide dismutase (SOD) and decreased the activity of lactate dehydrogenase (LDH) and the contents of malondialdehyde (MDA), nitric oxide (NO), and neuronal nitric oxide synthase (nNOS) in vivo and in vitro. In addition, geraniin significantly reduced the apoptosis. Furthermore, geraniin also evidently increased Nrf2 (total and nuclear) and HO-1 protein expression in vivo and in vitro. Collectively, these results imply that geraniin may exert a protective effect against cerebral I/R injury by suppressing oxidative stress and neuronal apoptosis. The mechanism underlying the protective effect of geraniin is associated with activation of the Nrf2/HO-1 pathway. Our results indicate that geraniin may be a potential drug candidate for the treatment of ischemic stroke.
Yang Y
，He B
，Zhang X
，Yang R
，Xia X
，Chen L
，Li R
，Shen Z
，Chen P
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Phelligridimer A enhances the expression of mitofusin 2 and protects against cerebral ischemia/reperfusion injury.
Mitochondrial dysfunction and endoplasmic reticulum (ER) stress play pivotal roles in the pathology of cerebral ischemia. In this study, we investigated whether phelligridimer A (PA), an active compound isolated from the medicinal and edible fungus Phellinus igniarius, ameliorates ischemic cerebral injury by restoring mitochondrial function and restricting ER stress. An in vitro cellular model of ischemic stroke-induced neuronal damage was established by exposing HT-22 neuronal cells to oxygen-glucose deprivation/reoxygenation (OGD/R). An in vivo animal model was established in rats subjected to middle cerebral artery occlusion/reperfusion (MCAO/R). The results showed that PA (1-10 μM) dose-dependently increased HT-22 cell viability, reduced OGD/R-induced lactate dehydrogenase release, and reversed OGD/R-induced apoptosis. PA reduced OGD/R-induced accumulation of reactive oxygen species, restored mitochondrial membrane potential, and increased ATP levels. Additionally, PA reduced the expression of the 78-kDa glucose-regulated protein (GRP78) and the phosphorylation of inositol-requiring enzyme-1α (p-IRE1α) and eukaryotic translation-initiation factor 2α (p-eIF2α). PA also inhibited the activation of the mitogen-activated protein kinase (MAPK) pathway in the OGD/R model. Moreover, treatment with PA restored the expression of mitofusin 2 (Mfn-2), a protein linking mitochondria and ER. The silencing of Mfn-2 abolished the protective effects of PA. The results from the animal study showed that PA (3-10 mg/kg) significantly reduced the volume of cerebral infarction and neurological deficits, which were accompanied by an increased level of Mfn-2, and decreased activation of the ER stress in the penumbra of the ipsilateral side after MCAO/R in rats. Taken together, these results indicate that PA counteracts cerebral ischemia-induced injury by restoring mitochondrial function and reducing ER stress. Therefore, PA might be a novel protective agent to prevent ischemia stroke-induced neuronal injury.
Li X
，Xu B
，Long L
，Li Y
，Xiao X
，Qiu S
，Xu J
，Tian LW
，Wang H
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