Ginkgo biloba leaf extract (EGb-761) elicits neuroprotection against cerebral ischemia/reperfusion injury by enhancement of autophagy flux in neurons in the penumbra

EGb761 suppressed vascular dementia via modulating Wnt/β-catenin signaling pathway-induced apoptosis and autophagy in hippocampal neuronal cells

OBJECTIVES

The study aimed to explore the effects of EGb761 on vascular dementia (VD) rats and the mechanisms of action.

METHODS

The Morris water maze test was utilized to assess the spatial learning and memory abilities of the rats; Hematoxylin and Eosin (HE) staining and electron microscopy were used to observe changes in hippocampal neuron cells; Immunohistochemistry was performed to detect the expression of cleaved caspase-3 and microtubule-associated proteins light chain 3 (LC3-II) positive cells in hippocampal neurons; immunofluorescence staining was carried out to determine the immunofluorescence intensity of IRGM in hippocampal neurons; western blotting was used to measure the expression of related proteins.

RESULTS

EGb761 significantly improved the cognitive function of vascular dementia rats (P < 0.01) and reduced the apoptosis of hippocampal neurons.Furthermore, EGb761 suppressed ROS, thereby promoting the expression of proteins related to the Wnt/β-catenin signaling pathway and inhibiting the expression of C-Jun N-terminal Kinase (p-JNK), c-Jun N-terminal kinase (p-c-JUN), Protein 53 (P53), immunity-related GTPase M (IRGM), Transcription Factor EB (TFEB), microtubule-associated proteins light chain 3 (LC3), Lysosomal Associated Membrane Protein 1 (LAMP1), and Sequestosome 1 (SQSTM1).

CONCLUSIONS

Ginkgo Biloba Extract 761 (EGb761) mediated the Wnt/β-catenin signaling pathway to inhibit apoptosis and autophagy in hippocampal neurons in VD rats.

Sodium formononetin-3'-sulphonate alleviates cerebral ischemia-reperfusion injury in rats via suppressing endoplasmic reticulum stress-mediated apoptosis

BACKGROUND

Sodium formononetin-3'-sulphonate (Sul-F) may alleviate I/R injury in vivo with uncertain mechanism. Endoplasmic reticulum (ER) stress-mediated apoptosis participates in the process of cerebral ischemia-reperfusion (I/R) injury. Our aim is to figure out the effect of Sul-F on cerebral I/R injury and to verify whether it works through suppressing ER stress-mediated apoptosis.

RESULTS

The cerebral lesions of middle cerebral artery occlusion (MCAO) model in SD rats were aggravated after 24 h of reperfusion, including impaired neurological function, increased infarct volume, intensified inflammatory response and poor cell morphology. After intervention, the edaravone (EDA, 3 mg/kg) group and Sul-F high-dose (Sul-F-H, 80 mg/kg) group significantly alleviated I/R injury via decreasing neurological score, infarct volume and the serum levels of inflammatory factors (TNF-α, IL-1β and IL-6), as well as alleviating pathological injury. Furthermore, the ER stress level and apoptosis rate were elevated in the ischemic penumbra of MCAO group, and were significantly blocked by EDA and Sul-F-H. In addition, EDA and Sul-F-H significantly down-regulated the ER stress related PERK/eIF2α/ATF4 and IRE1 signal pathways, which led to reduced cell apoptosis rate compared with the MCAO group. Furthermore, there was no difference between the EDA and Sul-F-H group in terms of therapeutic effect on cerebral I/R injury, indicating a therapeutic potential of Sul-F for ischemic stroke.

CONCLUSIONS

Sul-F-H can significantly protects against cerebral I/R injury through inhibiting ER stress-mediated apoptosis in the ischemic penumbra, which might be a novel therapeutic target for ischemic stroke.

EGCG protects the mouse brain against cerebral ischemia/reperfusion injury by suppressing autophagy via the AKT/AMPK/mTOR phosphorylation pathway

Stroke remains one of the leading reasons of mortality and physical disability worldwide. The treatment of cerebral ischemic stroke faces challenges, partly due to a lack of effective treatments. In this study, we demonstrated that autophagy was stimulated by transient middle cerebral artery occlusion/reperfusion (MCAO/R) and oxygen-glucose deprivation/reoxygenation (OGD/R). Treatment with (−)-epigallocatechin-3-gallate (EGCG), a bioactive ingredient in green tea, was able to mitigate cerebral ischemia/reperfusion injury (CIRI), given the evidence that EGCG administration could reduce the infarct volume and protect poststroke neuronal loss in MCAO/R mice in vivo and attenuate cell loss in OGD/R-challenged HT22 cells in vitro through suppressing autophagy activity. Mechanistically, EGCG inhibited autophagy via modulating the AKT/AMPK/mTOR phosphorylation pathway both in vivo and in vitro models of stroke, which was further confirmed by the results that the administration of GSK690693, an AKT/AMPK inhibitor, and rapamycin, an inhibitor of mTOR, reversed aforementioned changes in autophagy and AKT/AMPK/mTOR signaling pathway. Overall, the application of EGCG relieved CIRI by suppressing autophagy via the AKT/AMPK/mTOR phosphorylation pathway.