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
... -
《-》
Dexmedetomidine alleviates cerebral ischemia-reperfusion injury by inhibiting endoplasmic reticulum stress dependent apoptosis through the PERK-CHOP-Caspase-11 pathway.
Dexmedetomidine (Dex) has the neuroprotective effect on cerebral ischemia-reperfusion injury (CIRI). But the mechanism is not yet clear. In this study, we established a model of middle cerebral artery occlusion (MCAO) and treated primary cortical neurons with oxygen glucose deprivation (OGD), followed by Dex treatment. Neurological protection of Dex was then assessed by neurological deficit score, brain edema, TTC staining, TUNEL assay, Western blot analysis, immunohistochemistry, and RT-PCR. The results showed that Dex significantly reduced the neurological deficit score, brain edema and cerebral infarction area due to CIRI. After Dex treatment, the expression levels of ER stress-related apoptosis pathway proteins (GRP78, p-PERK, CHOP and Cleaved-caspase-3) were significantly decreased and the apoptosis of brain cells was also significantly reduced. Immunohistochemistry showed that expression and nuclear localization of CHOP decreased significantly after the application of Dex. The downstream apoptotic protein caspase-11 mediated by PERK-CHOP was also markedly inhibited by Dex. In conclusion, our results suggested that Dex reduced ER stress-induced apoptosis after CIRI. Its protective mechanism may be related to PERK-CHOP-Caspase-11 dependent signaling pathway.
Liu C
，Fu Q
，Mu R
，Wang F
，Zhou C
，Zhang L
，Yu B
，Zhang Y
，Fang T
，Tian F
... -
《-》
The Role of the GRP78/PERK/ATF4 Pathway in the Ability of Gua Lou Gui Zhi Decoction to Attenuate Apoptosis by Inhibiting Endoplasmic Reticulum Stress after Ischemia-Reperfusion Injury.
Endoplasmic reticulum stress (ERS) is a key part of the apoptotic cascade that is initiated after cerebral ischemia-reperfusion injury and is very important for research on poststroke rehabilitation. In addition, the unfolded protein response (UPR) plays an important role in ERS because it activates downstream apoptotic signal transduction and induces apoptosis through the glucose-regulated protein 78 (GRP78)/protein kinase R (PKR)-like ER kinase (PERK)/activating transcription factor 4 (ATF4) pathway. The Gua Lou Gui Zhi Decoction (GLGZD) ameliorated neuronal apoptosis of ischemia-reperfusion injury caused by middle cerebral artery occlusion (MCAO) had been proved in our previous study. The present study aims to underly the regulatory ability of GLGZD in ERS-induced apoptosis mediated by the GRP78/PERK/ATF4 pathway.
GLGZD was analyzed by HPLC. The effects of GLGZD were obversed on MCAO-induced ischemic rats. The cerebral infarct volume was detected by 2,3,5-Triphenyl-2H-Tetrazolium Chloride (TTC) Staining. Terminal Deoxynucleotidyl Transferase-Mediated dUTP-Biotin Nick End Labeling (TUNEL) were used to detect apoptosis. Transmission Electron Microscopy (TEM), Ca2+ levels and reactive oxygen species (ROS) detection were used to determine the function of endoplasmic reticulum. The GRP78/PERK/ATF4 signaling pathway was assessed by western blotting and immunohistochemistry.
Our results showed that GLGZD exerted its effects on ischemia-reperfusion injury by significantly promoting the restoration of the quantity and morphology of the rough ER and reducing the neuronal apoptosis rate in the ischemic cortex. Moreover, both of the intracellular ROS and Ca2+ levels in ischemic cortical cells were found significantly reduced by GLGZD. The GLGZD-treated group showed increased levels of phosphorylation in both of PERK and eukaryotic translation initiation factor 2α (eIF2α), activation of cysteinyl aspartate-specific proteinase-3 (Caspase-3), upregulation of the total protein levels of sarcoplasmic/endoplasmic Ca2+ ATPase 2α (SERCA 2α) and B-cell leukemia/lymphoma gene 2 (Bcl-2).
These findings suggest that GLGZD reduces oxidative stress-induced injury and promotes a dynamic calcium balance, thereby inhibiting ERS and exerting an antiapoptotic effect on neuronal ischemic injury, which are closely related to the activation of GRP78/PERK/ATF4 signaling pathway.
Chen Y
，Chen Z
，Cheng W
，Cao Y
，Xu W
，Lai W
，Zhang Y
，Huang M
，Nan L
... -
《-》
ResearchGate
(全网免费下载)
钛学术
(全网免费下载)
