ABSTRACT
OBJECTIVE: To explore whether the protective mechanism of ginkgolide K on cerebral focal ischemia reperfusion injury in rats induced by middle cerebral artery occlusion (MCAO) was associated with the amelioration of mitochondrial calcium uniporter ( MCU) or not. METHODS: Sprague Dawley (SD) rats were divided into 5 big groups randomly: sham operation group, MCAO group, GK added into RR group, GK group and GK added into SM group. The MCAO rat model were established after cerebral artery ischemia for 2 h and reperfusion for 22 h. Zea Longa 5 score system was used to evaluate neurological deficit score; Determination of brain water content and cerebral infarction areas were determined using gravimetric method and by triphenyltetrazolium chloride(TTC) staining method, respectively. In addition, malondialdehyde (MDA) and superoxide dismutase (SOD), nitric oxide synthase (NOS), nitric oxide (NO) were detected by Elisa. Additionally, mitochondrial[Ca2+] i concentration was estimated with the fluorescence spectrophotomete. The morphological change of the injured brains were observed by HE staining. The expression of caspase-3/8/9 protein were detected by Western blot. RESULTS: Compared with GK group, GK + RR group relieved obviously the neurological deficit score and reduced the cerebral infarction areas, brain water content, mitochondrial[Ca2+]i concentration and MDA, caspase-3/8/9 protein expression while enhance SOD activity. However, the effect of SM on the GK protective activity in MCAO rat injury was the opposite in comparison to GK + RR group. CONCLUSION: The stimulative effect of RR and the inhibitory effect of SM on the GK protection in MCAO rat had proves that the protective mechanism of GK on MCAO rat injury is associate with its down-regulation of the transport capacity of MCU, leading the attenuation of mitochondrial[Ca2+]i influx.
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Objective To prepare and characterize ginkgolide K-loaded mPEG-PLGA [poly (D,L-lactide-co-gly-colide)-block-poly (ethylene glycol)] polymer nanoparticles (GK-mPEG-PLGA-NPs) and to evaluate its neuroprotective effect on the H2O2-induced PC12 cells injury in vitro. Methods The PLGA-PEG-COOH polymer was selected as carrier and double emulsion solvent evaporation technique was employed to prepare the stealth nanoparticles. The encapsulation efficiency (EE) and drug load (DL) of GK-mPEG-PLGA-NPs were investigated by HPLC. The size distribution, zeta potential, and surface morphology of GK-mPEG-PLGA-NPs were characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM), respectively. The in vitro release of GK-mPEG-PLGA-NPs was examined using phosphate buffer solution (pH 7.4) as the releasing medium for 24 h. The H2O2-induced PC12 cells injury models was established for the investigation of the protective effect of GK-mPEG-PLGA-NPs on nerve cells in vitro. Results EE and DL of GK-mPEG-PLGA-NPs was (83.40 ± 2.85)% and (3.26 ± 0.24) mg/g, respectively. The average diameter of GK-mPEG-PLGA-NPs was (93.19 ± 2.77) nm and zeta potential was (-11.93 ± 1.71) mV. The cumulative rate of drug release was (90.5 ± 4.0)% after 60 h in phosphate buffer solution. GK-mPEG-PLGA-NPs significantly inhibited the apoptosis of PC12 cells and the release of lactic dehydrogenase induced by H2O2. However, the protective action of GK-mPEG-PLGA-NPs on the H2O2-iduced PC12 cells injury was significantly weaker than that of GK. Conclusion Our results proved that GK-mPEG-PLGA-NPs had a sustained release behavior in vitro and the neuroprotective effect of GK-mPEG-PLGA-NPs on H2O2-induced PC12 cells, which indicates that GK-mPEG-PLGA-NPs has the prospect of application and deserves further research. Key words: ginkgolide K; mPEG-PLGA; in vitro release; in vitro neuroprotection; d
ABSTRACT
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.
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To investigate the effects of ginkgolide A (GA), ginkgolide B (GB) and ginkgolide K (GK) on platelet aggregation in rabbits, and compare the similarities and differences among these three components. The effects of different doses of ginkgolide A, B and K on platelet aggregation induced by platelet activating factor (PAF) were observed by using in vitro experiment. The results showed that three compounds could inhibit platelet aggregation induced by PAF in vitro, and the intensity was GK> GB> GA. It was further found that all of them can mobilize [Ca2+]i and enhance intracellular c-AMP level in a dose-dependent manner, which was consistent to the ability to antagonize PAF receptor. These findings indicated that GK was highly selective for PAF receptor, and may inhibit platelet aggregation by activating cAMP signaling pathway and inhibiting intracellular [Ca2+]i mobilization; GB and GA also had strong antagonism to PAF receptor, but the effect was weaker than that of GK.
ABSTRACT
To investigate the antagonism effects of different concentrations of ginkgolide K(GK) on platelet activating factor (PAF)-induced platelet aggregation and neuroprotective effect on cells and animal models of ischemia-reperfusion injury. GK-containing serum in rabbit was prepared, and the effects of GK-containing serum on PAF-induced platelet aggregation was observed by platelet aggregation assay. The effect of different concentrations of GK on apoptosis of SH-SY5Y cells injured by oxygen-glucose deprivation/reoxygenation (OGD/R) was investigated by Hoechst 33342/PI double staining in OGD/R cell model. The focal cerebral ischemia-reperfusion model (I/R)was established in rats to detect the effects of GK on neurobehavioral scores and cerebral infarction volume. GK could inhibit PAF-induced platelet aggregation, reverse the apoptosis induced by OGD/R injury and improve the neurobehavioral score and cerebral infarction volume after cerebral ischemia-reperfusion injury in rats in a dose-dependent manner. GK can inhibit PAF-induced platelet aggregation and improve nerve injury after cerebral ischemia-reperfusion.