Standardized Ginkgo biloba extract EGb 761® attenuates early brain injury following subarachnoid hemorrhage via suppressing neuronal apoptosis through the activation of Akt signaling.

Early brain injury (EBI) plays a critical role in determining the outcome of subarachnoid hemorrhage (SAH). The present study was designed to investigate the role of EGb 761, a standardized extract of Ginkgo biloba, in SAH-induced EBI and to explore its potential mechanism of action. A rat SAH model was established by the endovascular perforation process. Doses of 10, 50 and 100 mg/kg EGb 761 were injected intraperitoneally 2 h after SAH was induced. Mortality, SAH grade, neurological score and brain water content were measured 24 h after SAH was induced. A Western blot assay was performed to assess the expression of the apoptosis-related proteins Bax, Bcl-2, cleaved caspase-3, Akt and phosphorylated Akt (p-Akt). Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) and neuronal nuclei (NeuN) double immunofluorescence staining were used to detect apoptotic neurons. Animals suffered from serious neurological deficits and increased brain water content after induction of SAH. Rats treated with EGb 761 experienced dose-dependent attenuation of neurological dysfunction and decreased brain water content. In addition, EGb 761 significantly activated Akt signaling accompanied by increased Bcl-2 levels and decreased expression of Bax and cleaved caspase-3. Moreover, EGb 761 decreased the number of TUNEL/NeuN-positive cells in a dose-dependent manner. However, all the beneficial effects of EGb 761 for SAH were abolished by the Akt inhibitor MK2206. Our results indicated that EGb 761 could ameliorate SAH-induced EBI and that the neuroprotective effects of EGb 761 against SAH were exerted via suppression of neuronal apoptosis through activation of the Akt pathway.

Yu T ，Fan Y ，Xu Y ，Xu L ，Xu G ，Cao F ，Jiang H ... -  《-》

Hydrogen-Rich Saline Attenuated Subarachnoid Hemorrhage-Induced Early Brain Injury in Rats by Suppressing Inflammatory Response: Possible Involvement of NF-κB Pathway and NLRP3 Inflammasome.

Shao A ，Wu H ，Hong Y ，Tu S ，Sun X ，Wu Q ，Zhao Q ，Zhang J ，Sheng J ... -  《-》

Ceftriaxone alleviates early brain injury after subarachnoid hemorrhage by increasing excitatory amino acid transporter 2 expression via the PI3K/Akt/NF-κB signaling pathway.

Early brain injury (EBI) after subarachnoid hemorrhage (SAH) is characterized by a reduction in excitatory amino acid transporter 2 (EAAT2) expression and severe amino acid excitotoxicity. The aim of this study was to explore the neuroprotective effect of ceftriaxone (CEF), a potent compound that up-regulates EAAT2, against EBI and the potential mechanisms using in vitro experiments and a rat model of SAH. Intracisternal treatment with CEF significantly improved neurological outcomes and alleviated extracellular glutamate accumulation after SAH. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay (TUNEL) staining and Western blot analysis of cleaved caspase 3 showed that CEF decreased hippocampal neuronal apoptosis following SAH. Immunofluorescent staining and Western blotting revealed that CEF significantly reversed the down-regulation of EAAT2 expression following SAH. In Morris water maze (MWM) tests, CEF remarkably ameliorated the SAH-induced cognitive dysfunction in spatial learning memory and reference memory. CEF promoted the nuclear translocation of p65 as well as the activation of Akt in hippocampal astrocytes in vitro and in vivo. These findings suggest that CEF may exert significant protective effects against EBI following SAH by modulating the PI3K/Akt/NF-κB signaling pathway.

Feng D ，Wang W ，Dong Y ，Wu L ，Huang J ，Ma Y ，Zhang Z ，Wu S ，Gao G ，Qin H ... -  《-》

Pharmacological Inhibition of PERK Attenuates Early Brain Injury After Subarachnoid Hemorrhage in Rats Through the Activation of Akt.

Yan F ，Cao S ，Li J ，Dixon B ，Yu X ，Chen J ，Gu C ，Lin W ，Chen G ... -  《-》

Apelin-13 attenuates early brain injury following subarachnoid hemorrhage via suppressing neuronal apoptosis through the GLP-1R/PI3K/Akt signaling.

Apelin, an endogenous ligand for the orphan G-protein-coupled receptor APJ, possesses anti-apoptotic and neuroprotective properties. It has been shown to be a protective factor for different types of central nervous system insults, such as ischemia and traumatic brain injury. Here, we investigated the effects of apelin-13 on early brain injury (EBI) following subarachnoid hemorrhage (SAH), and the underlying molecular mechanisms involved. Apelin-13 was delivered to rats via intracerebroventricular administration. Neurological scores, brain water content and neuronal apoptosis were measured 24 h after SAH. The PI3K/Akt inhibitor LY294002 or GLP-1R siRNA were injected into the lateral cerebral ventricle before induction of SAH. Changes in the expression of p-Akt, GLP-1R and apoptosis-associated proteins (Bax, Bcl-2, cleaved caspase-3) were then investigated. Results showed that the levels of GLP-1R in neurons increased significantly, reaching a peak at 24 h after the induction of SAH. Treatment with apelin-13 improved neurological deficits, as well as alleviated brain edema and apoptotic cell death. Apelin-13 was also able to increase the levels of p-Akt, GLP-1R and Bcl-2, while inhibiting the expression levels of Bax and cleaved caspase-3. The anti-apoptotic and neuroprotective effects of apelin-13 were partially reversed by addition of LY294002 or GLP-1R siRNA. These results provide evidence that apelin-13 attenuates EBI following SAH via suppressing neuronal apoptosis, and that this effect may act partially via the activation of the GLP-1R/PI3K/Akt signaling pathway.

Liu Y ，Zhang T ，Wang Y ，Wu P ，Li Y ，Wang C ，Xu S ，Shi H ... -  《-》