Protection of Momordica charantia polysaccharide against intracerebral hemorrhage-induced brain injury through JNK3 signaling pathway.

It has been well documented that Momordica charantia polysaccharide (MCP) has multiple biological effects such as immune enhancement, anti-oxidation and anti-cancer. However, the potential protective effects of MCP on stroke damage and its relative mechanisms remain unclear. Our present study demonstrated that MCP could scavenge reactive oxygen species (ROS) in intra-cerebral hemorrhage damage, significantly attenuating the neuronal death induced by thrombin in primary hippocampal neurons. Furthermore, we found that MCP prevented the activation of the c-Jun N-terminal protein kinase (JNK3), c-Jun and caspase-3, which was caused by the intra-cerebral hemorrhage injury. Taken together, our study demonstrated that MCP had a neuroprotective effect in response to intra-cerebral hemorrhage and its mechanisms involved the inhibition of JNK3 signaling pathway.

Cardioprotection of ginsenoside Rb1 against ischemia/reperfusion injury is associated with mitochondrial permeability transition pore opening inhibition.

OBJECTIVE: To investigate the role of ginsenoside Rb1 (Gs-Rb1) in cardioprotection against ischemia/reperfusion (I/R) or hypoxia/reoxygenation (H/R) injury and to explore whether the cardioprotective action is mediated via attenuating the formation of mitochondrial permeability transition pore (mPTP). METHODS: A Langendorff-perfused model of rat heart was employed. I/R injury was induced by breaking off perfusion for 40 min then reperfusion for 60 min. Gs-Rb1 (100 µmol/L) were administrated for 10 min before I/R. Infarct size was estimated by the 2,3,5-triphenyl tetrazolium chloride (TTC) staining. Lactate dehydrogenase (LDH) and creatine kinase (CK) released from effluents were measured. Transmission electron microscopy was performed to assess morphological difference between cardiac mitochondrial isolated from I/R rats and Gs-Rb1 pretreated rats. Western blot analysis was used to determine phosphorylation of protein kinase B/Akt, and its downstream target glycogen synthase kinase 3ß (GSK-3ß). Incubation isolated cardiac mitochondria with Gs-Rb1, Ca2+-induced opening of the mPTP was assessed by the reduction of absorbance at 520 nm (A520). Neonatal rat cardiomyocytes were subjected to hypoxia 9 h followed by reoxygenation 4 h to induce H/R injury. After pretreated with different concentration of Gs-Rb1 (6.25, 25, 100 µmol/L ), cell viability was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) method. The membrane potential was estimated by Rh123 fluorescence. mPTP opening was measured using the probe calcein-AM. RESULTS: Gs-Rb1 100 µmol/L significantly reduced the infarct size of hearts (26.39%±11.67% vs. I/R group 56.68%±5.88%, P<0.01). Compared with the I/R group, Gs-Rb1 pretreatment decreased LDH and CK levels in the coronary effluent (P<0.05 or P<0.01) as well as attenuated destructive ultrastructure induced by I/R. The protective effect of Gs-Rb1 involved in phosphorylating protein kinase B/PKB (Akt) and GSK-3ß. In mitochondria isolated from rat hearts, significant inhibition of Ca2+-induced swelling was observed in samples that were pretreated with Gs-Rb1 (6.25, 25, 100, 400 µmol/L) for 10 min. When cardiomyocytes were isolated from neonatal rat and subjected to H/R, cell viability was increased with treatment of Gs-Rb1 (6.25, 25, 100 µmol/L ). Gs-Rb1 inhibited mPTP opening and restored subsequent loss of mitochondrial membrane potential. CONCLUSION: Gs-Rb1 presents cardioprotective effect against I/R or H/R injury which involves in activating Akt, phosphorylating GSK-3ß and inhibiting mPTP opening.

Protease activated receptor 1 (PAR1) enhances Src-mediated tyrosine phosphorylation of NMDA receptor in intracerebral hemorrhage (ICH).

It has been demonstrated that Src could modulate NMDA receptor, and PAR1 could also affect NMDAR signaling. However, whether PAR1 could regulate NMDAR through Src under ICH has not yet been investigated. In this study, we demonstrated the role of Src-PSD95-GluN2A signaling cascades in rat ICH model and in vitro thrombin challenged model. Using the PAR1 agonist SFLLR, antagonist RLLFS and Src inhibitor PP2, electrophysiological analysis showed that PAR1 regulated NMDA-induced whole-cell currents (INMDA) though Src in primary cultured neurons. Both in vivo and in vitro results showed the elevated phosphorylation of tyrosine in Src and GluN2A and enhanced interaction of the Src-PSD95-GluN2A under model conditions. Treatment with the PAR1 antagonist RLLFS, AS-PSD95 (Antisense oligonucleotide against PSD95) and Src inhibitor PP2 inhibited the interaction among Src-PSD95-GluN2A, and p-Src, p-GluN2A. Co-application of SFLLR and AS-PSD95, PP2, or MK801 (NMDAR inhibitor) abolished the effect of SF. In conclusion, our results demonstrated that activated thrombin receptor PAR1 induced Src activation, enhanced the interaction among Src-PSD95-GluN2A signaling modules, and up-regulated GluN2A phosphorylation after ICH injury. Elucidation of such signaling cascades would possibly provide novel targets for ICH treatment.

Danhong injection protects cardiomyocytes against hypoxia/reoxygenation- and H2O2-induced injury by inhibiting mitochondrial permeability transition pore opening.

ETHNOPHARMACOLOGICAL RELEVANCE: Danhong injection (DHI), a Chinese medical product extracted from Radix et Rhizoma Salviae Miltiorrhizae (Salvia miltiorrhiza Bge., Labiatae, Danshen in Chinese) and Flos Carthami (Carthamus tinctorius L., Compositae, Honghua in Chinese), has been widely used for the treatment of ischemic heart disease, and clinical and experimental studies have demonstrated the protective effects against myocardial ischemia/reperfusion injury. Nevertheless, the underlying cellular mechanisms responsible for this protective effect are poorly understood. AIM OF THE STUDY: The present study aimed to examine the mechanism of DHI in regulating hypoxia/reoxygenation- and H2O2-induced cardiomyocytes injury. MATERIALS AND METHODS: Neonatal rat cardiomyocytes were subjected to hypoxia (9h)-reoxygenation (2h) or H2O2 (100 µM) in the presence or absence of DHI (2.5, 5, 10 µg/mL). Intracellular reactive oxygen species (ROS), cytosolic and mitochondrial Ca(2+) concentrations, mitochondrial membrane potential (ΔΨm) and mitochondrial permeability transition pore (mPTP) opening were monitored using CMH2DCFDA, Fluo-4 and rhod-2, JC-1 and calcein, respectively. Cell survival was evaluated using the 2-(4,5-dimethylthiazol-2-yl)-2,5 -diphenyltetrazolium bromide (MTT) assay and apoptosis was detected by Annexin V/propidium iodide (PI) staining. RESULTS: DHI improved cell survival following H/R and H2O2 injury and reduced H/R-induced cytochrome c release and apoptosis when compared with non-DHI treated cells. In addition, DHI attenuated H/R-induced ROS generation, H2O2-induced cytosolic and mitochondrial Ca(2+) overload, and cellular ROS generation when compared with H/R- and H2O2-only groups. Moreover, DHI significantly inhibited both mPTP opening and ΔΨm depolarization. CONCLUSION: These data demonstrate that the protective mechanism of DHI against H/R- and H2O2-induced injury is mediated by the inhibition of mPTP opening via mitigating Ca(2+) overload and ROS generation.

The coronary dilation effect of shen fu injection was mediated through NO.

OBJECTIVES: Shen Fu Injection (SF), which consisted of Red ginseng extraction injection (RG) and prepared aconite extraction injection (RA), is a traditional Chinese medicine mainly used for various cardiac diseases. This study is to analyse SF's effects on cardiac performance and coronary circulation. And the coronary dilating effect and mechanism of the above three injections were also explored. METHODS: Mature male guinea pigs were used as our animal model. We employed two types of perfusion methods (constant pressure and constant flow) in vitro, using Langendorff heart preparations to observe the cardiac function and coronary response to SF (1/200). The coronary dilation effects of the above three injections (1/800, 1/400 and 1/200) were recorded at basal coronary resting tone and when coronary vessels were pre-contracted with a thromboxane A2 analogue (U46619), in the presence or the absence of the inhibitor of nitric oxide synthesis (L-NAME, 10-4 M), the blocker of Ca2+-activated potassium channel(TEA, 10-3 M), or the blocker of adenosine triphosphate (ATP)-sensitive potassium channel (glybenclamide) (10-5 M). RESULTS: When perfused with constant pressure, SF significantly increased coronary flow, left ventricular developed pressure (LVDP) and the rate-pressure product (RPP). When perfused with constant flow, SF produced a significant reduction in the coronary perfusion pressure (CPP), LVDP and RPP. The coronary vasodilatation response of the above three injections can be reduced by L-NAME but was unaffected by TEA or glybenclamide when coronary vessels were pre-contracted with U46619 but not at resting tone. SF, RG and RA can all up-regulate eNOS expression in the human umbilical vein cells (EA.hy926). CONCLUSION: We demonstrated that SF does not contribute to the inotropic change of myocardium whose improvement is due to alternation of coronary flow. The coronary dilation effect of SF was mediated through RG and RA, via promoting NO release.