ginkgolide-k and Brain-Ischemia

To investigate the best active compatibility of ginkgolide A, B and K (GA，GB，GK). The effects of GA, GB, GK alone, combinations of each two of them, and combinations of these three components on platelet-activating factor (PAF)-induced platelet aggregation activity and rat cerebral ischemia reperfusion model (tMCAO) were compared in this study. Different compatibilities of GA, GB and GK could significantly reduce the maximum aggregation rate of PAF-induced platelet aggregation, and the effect was most obvious in combination of the three. Different compatibilities of GA, GB and GK could alleviate the neural function, cerebral infarction volume and cerebral edema in the tMCAO model of rats to different degrees, and the effect of combinations of the three was stronger than those of combinations of two and single use. The combination of all of GA, GB and GK had the strongest effect on nerve injury caused by anti-platelet aggregation in tMCAO rats.

Topics: Animals; Brain Ischemia; Ginkgolides; Lactones; Platelet Activating Factor; Platelet Aggregation; Rats; Reperfusion Injury

The purpose of the present study was to explore the protective effect and functional mechanism of ginkgolide K (GK: C20H22O9) on cerebral ischemia. SH‑SY5Y cells were exposed to oxygen‑glucose deprivation (OGD) to simulate an ischemic model in vitro. Cell viability, reactive oxygen species (ROS), nuclear staining with Hoechst 33258 and mitochondrial membrane potential were detected following 4 h of exposure to OGD. Subsequently, the expression levels of the apoptosis‑related proteins, caspase‑9, caspase‑3, Bcl‑2, Bax, p53 and c‑Jun, as well as the mitogen‑activated protein kinases (MAPKs) signaling molecules were detected by western blot analysis. GK significantly elevated the cell viability and decreased the generation of ROS and the number of apoptotic cells in a dose‑dependent manner. Furthermore, GK markedly decreased the protein expression levels of p‑p38, p‑JNK, p‑p53, p‑c‑Jun and the expression levels of Bcl‑2, Bax, cleaved caspase‑9 and caspase‑3. In conclusion, GK demonstrated a neuroprotective effect on the simulated cerebral ischemia in vitro, and this effect was mediated through the inhibition of the mitochondria‑mediated apoptosis pathway triggered by ROS‑evoked p38 and JNK activation.

Topics: Apoptosis; Brain Ischemia; Cell Line; Cell Survival; Ginkgolides; Glucose; Humans; Lactones; MAP Kinase Signaling System; Membrane Potential, Mitochondrial; Neuroprotective Agents; Oxygen

Ginkgolide K (GK) belongs to the ginkgolide family of natural compounds found in Ginkgo biloba leaves, which have been used for centuries to treat cerebrovascular and cardiovascular diseases. We evaluated the protective effects of GK against neuronal apoptosis by assessing its ability to sustain mitochondrial integrity and function. Co-immunoprecipitation showed that Drp1 binding to GSK-3β was increased after an oxygen-glucose deprivation/reperfusion (OGD/R) insult in cultured neuroblastoma cells. This induced Drp1 and GSK-3β translocation to mitochondria and mitochondrial dysfunction, which was attenuated by GK. GK also reduced mitochondrial fission by increasing Drp1 phosphorylation at Ser637 and inhibiting mitochondrial Drp1 recruitment. In addition, GK exposure induced GSK-3β phosphorylation at Ser9 and enhanced the interaction between adenine nucleotide translocator (ANT) and p-GSK-3β. This interaction suppressed the interaction between ANT and cyclophilin D (CypD), which inhibited mitochondrial permeability transition pore (mPTP) opening. Similarly, suppression of mitochondrial fission by Mdivi-1 also inhibited GSK-3β-induced mPTP opening. Treating mice with GK prevented GSK-3β and Drp1 translocation to mitochondria and attenuated mitochondrial dysfunction after middle cerebral artery occlusion. We therefore propose that by inhibiting mitochondrial fission and attenuating mPTP opening, GK exerts neuroprotective effects that mitigate or prevent neuronal damage secondary to ischemic stroke.

Topics: Animals; Apoptosis; Brain Ischemia; Cell Line; Cytochromes c; Dynamins; Ginkgolides; Glucose; Glycogen Synthase Kinase 3 beta; Ion Channel Gating; Lactones; Male; Mice; Mitochondrial Dynamics; Mitochondrial Membrane Transport Proteins; Mitochondrial Permeability Transition Pore; Neurons; Neuroprotective Agents; Oxygen; Protein Transport; Reactive Oxygen Species; Reperfusion Injury; Stroke

Mitochondria and oxidative stress play important roles in neuronal cell death associated with cerebral ischemia. Elevated level of reactive oxygen species (ROS) and mitochondrial dysfunction are thought to be responsible for cerebral ischemia injury along with neural cells death through several apoptotic mechanisms. In this study, exposure of rat pheochromocytoma (PC12) cells to hydrogen peroxide (H2O2) at the concentration of 0.3 mM for 24 h caused significant loss of cell viability, lactate dehydrogenase (LDH) release from cells, ascent of ROS level and mitochondrial membrane potential (MMP) decrease. Moreover, the activities of caspase-9, caspase-8 and caspase-3 all were increased in H2O2-induced PC12 cells. However, pretreatment with ginkgolide K (GK) solutions of different concentrations (10, 50, 100 µM) for 24 h prior to exposuring to H2O2 significantly increased cells viability, suppressed LDH release, attenuated ROS level, prevented cytochrome c release from mitochondria and boosted MMP expression. In addition, ginkgolide K notably inhibited the caspase-3 and caspase-9 but not caspase-8 activities in exogenous H2O2-treated PC12 cells. These results demonstrated that ginkgolide K protected PC12 cells from H2O2-induced apoptosis by restoring MMP expression, ameliorating oxidative stress and subsequently leading to inhibit the activity of caspase-3 protein. Therefore, the present study supported that ginkgolide K may be a promising neuroprotective compound for cerebral ischemia treatment.

Topics: Animals; Antioxidants; Apoptosis; Brain Ischemia; Caspases; Cell Survival; Cytochromes c; Ginkgo biloba; Ginkgolides; Hydrogen Peroxide; L-Lactate Dehydrogenase; Lactones; Membrane Potential, Mitochondrial; Mitochondria; Neuroprotective Agents; Oxidative Stress; PC12 Cells; Phytotherapy; Plant Extracts; Proto-Oncogene Proteins c-bcl-2; Rats; Reactive Oxygen Species

Ginkgolide K, a natural platelet-activating factor receptor antagonist, was isolated from the leaves of Ginkgo biloba. However, little is known about its neuroprotective effect in ischemia-reperfusion (I/R)-induced cerebral injury. Hence, the present study was carried out to investigate the effect of ginkgolide K on neuroprotection and the potential mechanisms in the rat I/R model induced by middle cerebral artery occlusion (MCAO). The rats were pretreated with ginkgolide K 2, 4 and 8 mg/kg (i.v.) once a day for 5 days before MCAO. Neurological deficit score (NDS), brain water content, 2,3,5-triphenyltetrazolium chloride (TTC) staining and pathology of brain tissue, as well as indexes of oxidative stress [superoxide dismutase (SOD), malondialdehyde (MDA), nitric oxide (NO) and nitric oxide synthase (NOS)] were measured at 24 h after ischemia. The results indicated that pretreatment with ginkgolide K significantly diminished the volume of infarction and brain water content, and improved NDS. Moreover, ginkgolide K markedly reversed the level of MDA, NO, NOS and SOD to their normal state in serum or cerebral ischemic section. In addition, hematoxylin and eosin staining showed the neuronal injury was significantly improved after being pretreated with ginkgolide K. These findings demonstrate that ginkgolide K exhibits neuroprotective properties through its antioxidative action in MCAO rats.

Topics: Animals; Antioxidants; Brain; Brain Edema; Brain Ischemia; Disease Models, Animal; Ginkgolides; Infarction, Middle Cerebral Artery; Lactones; Male; Malondialdehyde; Neuroprotective Agents; Nitric Oxide; Nitric Oxide Synthase; Oxidative Stress; Rats; Rats, Sprague-Dawley; Stroke; Superoxide Dismutase