Folium Ginkgo extract and tetramethylpyrazine sodium chloride injection (Xingxiong injection) protects against focal cerebral ischaemia/reperfusion injury via activating the Akt/Nrf2 pathway and inhibiting NLRP3 inflammasome activation.

CONTEXT: Folium Ginkgo extract and tetramethylpyrazine sodium chloride injection (Xingxiong injection) is a compound preparation commonly used for treating cerebral ischaemia/reperfusion injury in ischaemic stroke in China. However, its potential mechanisms on ischaemic stroke remain unknown. OBJECTIVE: This study explores the potential mechanisms of Xingxiong injection in vivo or in vitro. MATERIALS AND METHODS: Sprague-Dawley (SD) rats were randomly assigned to five groups: the sham (normal saline), the model (normal saline) and the Xingxiong injection groups (12.5, 25 or 50 mL/kg). The rats were subjected to 2 h of middle cerebral artery occlusion (MCAO) followed by reperfusion for 14 d. Xingxiong injection was administered via intraperitoneal (i.p.) injection immediately after ischaemia induction for 14 d. Afterwards, rats were sacrificed at 14 d induced by administration of Xingxiong injection. RESULTS: Xingxiong injection significantly reduces infarct volume (23%) and neurological deficit scores (93%) compared with the MCAO/R group. Additionally, Xingxiong injection inhibits the loss in mitochondrial membrane potential (43%) and reduces caspase-3 level (44%), decreases NOX (41%), protein carbonyl (29%), 4-HNE (40%) and 8-OhdG (41%) levels, inhibits the expression of inflammatory factors, such as TNF-α (26%), IL-1ß (34%), IL-6 (39%), MCP-1 (36%), CD11a (41%) and ICAM-1 (43%). Moreover, Xingxiong injection can increase p-Akt/Akt (35%) and Nrf2 (47%) protein expression and inhibit NLRP3 (42%) protein expression. CONCLUSIONS: Xingxiong injection prevents cerebral ischaemia/reperfusion injury via activating the Akt/Nrf2 pathway and inhibiting NLRP3 inflammasome. These findings provide experimental evidence for clinical use of drugs in the treatment of ischaemic stroke.

Notoginsenoside R1 activates the NAMPT-NAD+-SIRT1 cascade to promote postischemic angiogenesis by modulating Notch signaling.

Nicotinamide phosphoribosyltransferase (NAMPT) maintains mitochondrial function and protects against cerebral ischemic injury by improving energy metabolism. Notoginsenoside R1 (R1), a unique constituent of Panax notoginseng, has been shown to promote the proliferation and tube formation of human umbilical vein endothelial cells. Whether R1 has proangiogenesis on the activation of NAMPT in ischemic stroke remains unclear. The purpose of this study was to investigate the pharmacodynamic effect and mechanism of R1 on angiogenesis after ischemic stroke. We used male Sprague-Dawley (SD) rats subjected to middle cerebral artery occlusion/reperfusion (MCAO/R). R1 was administered via intraperitoneal (i.p.) injection immediately after ischemia induction. The promotion of R1 on angiogenesis were detected by immunofluorescence staining, 3D stereoscopic imaging and transmission electron microscopy detection. HBMEC cells were pretreated with different concentrations of R1 for 12 h before oxygen-glucose deprivation/reoxygenation (OGD/R) exposure. Afterward, scratch assay, EdU staining and tube formation were determined. Western blot analyses of proteins, including those involved in angiogenesis, NAMPT-SIRT1 cascade, VEGFR-2, and Notch signaling, were conducted. We showed that R1 significantly restored cerebral blood flow, improved mitochondrial energy metabolism and promoted angiogenesis. More importantly, incubation with 12.5-50 µM R1 significantly increased the migration, proliferation and tube formation of HBMECs in vitro. The promotion of R1 on angiogenesis were associated with the NAMPT-NAD+-SIRT1 cascade and Notch/VEGFR-2 signaling pathway, which was partially eliminated by inhibitors of NAMPT and SIRT1. We demonstrated that R1 promotes post-stroke angiogenesis via activating NAMPT-NAD+-SIRT1 cascade. The modulation of Notch signaling and VEGFR-2 contribute to the post-stroke angiogenesis. These findings offer insight for exploring new therapeutic strategies for neurorestoration via R1 treatment after ischemic stroke.

Cassane diterpenoid derivative induces apoptosis in IDH1 mutant glioma cells through the inhibition of glutaminase in vitro and in vivo.

BACKGROUND: Glioblastoma multiforme (GBM) is the most frequent, lethal and aggressive tumour of the central nervous system in adults. The discovery of novel anti-GBM agents based on the isocitrate dehydrogenase (IDH) mutant phenotypes and classifications have attracted comprehensive attention. PURPOSE: Diterpenoids are a class of naturally occurring 20-carbon isoprenoid compounds, and have previously been shown to possess high cytotoxicity for a variety of human tumours in many scientific reports. In the present study, 31 cassane diterpenoids of four types, namely, butanolide lactone cassane diterpenoids (I) (1-10), tricyclic cassane diterpenoids (II) (11-15), polyoxybutanolide lactone cassane diterpenoids (III) (16-23), and fused furan ring cassane diterpenoids (IV) (24-31), were tested for their anti-glioblastoma activity and mechanism underlying based on IDH1 mutant phenotypes of primary GBM cell cultures and human oligodendroglioma (HOG) cell lines. RESULTS: We confirmed that tricyclic-type (II) and compound 13 (Caesalpin A, CSA) showed the best anti-neoplastic potencies in IDH1 mutant glioma cells compared with the other types and compounds. Furthermore, the structure-relationship analysis indicated that the carbonyl group at C-12 and an α, ß-unsaturated ketone unit fundamentally contributed to enhancing the anti-glioma activity. Studies investigating the mechanism demonstrated that CSA induced oxidative stress via causing glutathione reduction and NOS activation by negatively regulating glutaminase (GLS), which proved to be highly dependent on IDH mutant type glioblastoma. Finally, GLS overexpression reversed the CSA-induced anti-glioma effects in vitro and in vivo, which indicated that the reduction of GLS contributed to the CSA-induced proliferation inhibition and apoptosis in HOG-IDH1-mu cells. CONCLUSION: Therefore, the present results demonstrated that compared with other diterpenoids, tricyclic-type diterpenoids could be a targeted drug candidate for the treatment of secondary IDH1 mutant type glioblastoma through negatively regulating GLS.

Xuesaitong injection (lyophilized) combined with aspirin and clopidogrel protect against focal cerebral ischemic/reperfusion injury in rats by suppressing oxidative stress and inflammation and regulating the NOX2/IL-6/STAT3 pathway.

BACKGROUND: Combination of aspirin (ASA) and clopidogrel (CLP) [dual antiplatelet therapy (DAPT)] has been limited in reducing early recurrent stroke events. Xuesaitong injection (lyophilized) (XST) made of total saponins from P. notoginseng, which significantly improves cerebral circulation and has been widely used in clinical applications for decades to treat and prevent ischemic stroke. Here, we confirmed the protective effect and mechanism of XST combined with DAPT (XST+ASA+CLP) on cerebral ischemia/reperfusion injury, exploring their better pharmacological action for clinical patients. METHODS: Sprague-Dawley rats (SD rats) (n=9 in each group) were randomly assigned to three groups and pretreated with XST, ASA+CLP, or XST+ASA+CLP for 7 days. Then rats were subjected to 2 h of middle cerebral artery occlusion (MCAO) followed by reperfusion for 24 h. Therapeutic effect of XST+ASA+CLP was measured by infarct volume, neurological behavior and regional cerebral blood flow (rCBF). Inhibition of neuronal apoptosis and glial cells was determined by immunofluorescent staining. We studied the protein levels of neurotrophic factors, neuroplasticity-related factors, oxidative stress indicators and inflammatory factors by ELISA assay. RESULTS: XST+ASA+CLP group showed significant reduction in infarct volumes and neurological deficit scores. XST+ASA+CLP group also had higher levels in rCBF and synaptic growth, and showed remarkable inhibition of microglia and astrocytes activation and the neuronal apoptosis. In addition, XST+ASA+CLP group had lower levels of NADPH, protein carbonyl, 4-hydroxynonenal (4-HNE), 8-hydroxydeoxyguanosine (8-OHdG) and several inflammatory cytokines. Moreover, XST+ASA+CLP group also had lower levels of NOX2, inducible nitric oxide synthase (iNOS), interleukin (IL)-6, and p-STAT3/STAT3. CONCLUSIONS: These results demonstrate that a combination of XST, ASA, and CLP effectively protected rats against middle cerebral artery occlusion/reperfusion (MCAO/R) injury by suppressing the NOX2/IL-6/ STAT3 pathway. These novel findings provide theoretical basis and experimental evidence for the rationality of clinical combined use of drugs in the treatment of ischemic stroke.

Xuezhitong capsule, an extract of Allium macrostemon Bunge, exhibits reverse cholesterol transport and accompanies high-density lipoprotein levels to protect against hyperlipidemia in ApoE-/- mice.

BACKGROUND: Xuezhitong capsules (XZT) are derived from Xie Bai and used for abnormal lipid homeostasis treatment through maintained metabolic balance. However, their mechanisms are largely unknown. Here, we mainly assessed the contribution of reverse cholesterol transport (RCT) and the accompanying increase in the high-density lipoprotein (HDL) effects of XZT to cholesterol dysfunction amelioration in mice. METHODS: We assessed serum lipids by using enzymatic kits. We observed atherosclerotic plaque formation by hematoxylin-eosin (HE) and Oil Red O staining. We studied the lipid metabolism, fatty acid synthase (FAS), HDL, low-density lipoprotein receptor (LDLR), triglyceride (TG) metabolic enzyme expression levels, and RCT function in various tissues upon stimulation with high-fat diet, XZT, and some positive drugs by ELISA. RESULTS: After 34 weeks of high-fat diet administration, blood lipids levels increased because attenuated by XZT treatment (800 and 1,600 mg/kg, i.g.). XZT improved the lipid metabolism instability, induced RCT activation, and subsequently increased the HDL levels in hyperlipidemic mice (P<0.05). FAS (P<0.05) and LDLR (P<0.01) levels also remarkably improved. The effects of XZT were closely associated with RCT activation and the accompanying increase in the HDL levels, as characterized by XZT-induced preservation in ATP-binding cassette transporter member 1 (ABCA1), scavenger receptor class B type 1 (SRB1), acyl coenzyme A: cholesterol acyltransferase (ACAT), lecithin cholesterol acyltransferase (LCAT), apolipoprotein A I (ApoA1) and apolipoprotein B (ApoB). However, XZT showed no effect on high fat diet-activated TG metabolic enzyme expression levels (P>0.05). CONCLUSIONS: XZT are promising drugs in balancing the cholesterol dysfunction from hyperlipidemia through RCT activation and accompanying increase in HDL levels.

Protective effects of Araloside C against myocardial ischaemia/reperfusion injury: potential involvement of heat shock protein 90.

The present study was designed to investigate whether Araloside C, one of the major triterpenoid compounds isolated from Aralia elata known to be cardioprotective, can improve heart function following ischaemia/reperfusion (I/R) injury and elucidate its underlying mechanisms. We observed that Araloside C concentration-dependently improved cardiac function and depressed oxidative stress induced by I/R. Similar protection was confirmed in isolated cardiomyocytes characterized by maintaining Ca2+ transients and cell shortening against I/R. Moreover, the potential targets of Araloside C were predicted using the DDI-CPI server and Discovery Studio software. Molecular docking analysis revealed that Araloside C could be stably docked into the ATP/ADP-binding domain of the heat shock protein 90 (Hsp90) protein via the formation of hydrogen bonds. The binding affinity of Hsp90 to Araloside C was detected using nanopore optical interferometry and yielded KD values of 29 µM. Araloside C also up-regulated the expression levels of Hsp90 and improved cell viability in hypoxia/reoxygenation-treated H9c2 cardiomyocytes, whereas the addition of 17-AAG, a pharmacologic inhibitor of Hsp90, attenuated Araloside C-induced cardioprotective effect. These findings reveal that Araloside C can efficiently attenuate myocardial I/R injury by reducing I/R-induced oxidative stress and [Ca2+ ]i overload, which was possibly related to its binding to the Hsp90 protein.

Convergent synthesis of oligosaccharides on the gram-scale using cetyl thioglycoside based on a hydrophobically assisted switching phase method.

A hydrophobically assisted switching phase (HASP) method is an efficient strategy for the synthesis of carrier-loaded oligosaccharides. We improved this method by using cetyl thioglycoside as the carrier, which made it possible to use the synthetic oligosaccharide block directly as the donor. We applied this improved HASP method in the successful assembly of a gp120-associated nona-mannoside. Our results indicated that the HASP method is an efficient strategy for the synthesis of complex oligosaccharides and glycoconjugates.

[Protective effects and underlying mechanisms of Panax notoginseng saponins against SH-SY5Y cell apoptosis induced by 6-hydroxydopamine].

The aim of this study is to investigate the protective effects of Panax notoginseng saponins (PNS) against 6-hydroxydopamine(6-OHDA)-induced apoptosis in SH-SY5Y cells and the possible underlying mechanisms. Cell viability was examined by MTT assay. The levels of lactate dehydrogenase(LDH), reactive oxygen species (ROS), malondialdehyde (MDA) and the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase(GSH-Px) were measured using the respective assay kits. Apoptosis was measured by TUNEL kit, JC-1 and ROS was measured by staining with fluorescent dyes. The activation of caspase-3 was measured with the caspase-3 assay kit. The expression of nuclear protein Nrf2 and HO-1 were determined by Western blot. PNS had significant protective effects against 6-OHDA-induced apoptosis in SH-SY5Y cells in a time- and dose-dependent manner. PNS could attenuate 6-OHDA-induced suppression of SOD, GAT, GSH-Px (P < 0.01). PNS reduced the level of LDH, decreased the levels of ROS, MDA and increased cell viability and the mitochondrial membrane potential (P < 0.01). PNS also inhibited DNA fragmentation, mitochondrial response and the activation of caspase-3 (P < 0.01). Moreover, PNS pretreatment increased the expression of the nuclear Nrf2 and up-regulate HO-1. The protective effects of PNS could be inhibited by HO-1 inhibitor SnPP. In conclusion, PNS has significant protective effects against 6-OHDA- induced apoptosis in SH-SY5Y cells. The possible mechanisms of PNS are due to PNS-mediated activation of Nrf2, up-regulation of HO-1 and inhibition of oxidative stress.

[Effects of Qizhi Jiangtang capsule on protein expressions of InsR, PI3K, GLUT2 and p-JNK in hepatic tissues of rats with type 2 diabetes].

To observe the hypoglycemic effect of Qizhi Jiangtang capsule in rats with type 2 diabetes, and investigate the preliminary mechanism of its hypoglycemic effect, type 2 diabetes rat models were established by high glucose and high fat combined with small dose of streptozotocin (STZ). After continuous administration for 6 weeks, blood glucose, and glycosylated serum protein (GSP) levels were detected in all of the animals; immunohistochemistry assay was used to detect the number of islet ß cells; Western blot assay was used to detect the protein expression levels of insulin receptor (InsR), phosphoinositide-3 kinases (PI3K), glucose transporter-2 (GLUT2) and phosphorylated Jun N-terminal kinases (p-JNK)in hepatic tissues. The results showed that Qizhi Jiangtang capsule could reduce the blood sugar and GSP levels in serum in animals with type 2 diabetes mellitus, increase the level of insulin in serum and number of islet ß cells, increase the protein expression levels of InsR, PI3K and GLUT2, and reduce the level of p-JNK protein expression. In conclusion, Qizhi Jiangtang capsule has relatively stable hypoglycemic effect, and the mechanism may be associated with increasing the number of islet ß cells and level of insulin in serum, up-regulating the protein expression levels of InsR, PI3K and GLUT2, down-regulating the level of p-JNK protein expression in hepatic tissues, and reducing the level of insulin in hepatic tissues.

[Effects of Qizhi Jiangtang capsule on dermal ulcer in type 2 diabetic rats].

The effect of Qizhi Jiangtang vapsule (QJC) on degree of dermal ulcer cicatrization in 2 type diabetic rats was studied. Except the rats for blank group, other male Wistar rats were used to establish type 2 diabetic model by feeding with high sugar and high fat diet for four weeks and intraperitonally injecting with 30 mg•kg⁻¹ streptozotocin (STZ). After that, the rats were divided into balanced groups according to blood sugar, and received corresponding drugs for treatment for 8 weeks. At the end of week 8, 2 cm diameter circular incision was done on the back of rats. After that, the rats were administered continuously for10 days. Area of ulcer surface was detected every two days. After the last administration, wound granulation tissues were cut down to conduct pathological examination and detect the expression of VEGF, PI3K, p-ERK protein in wound tissues. The results showed that compared with the model group, after application of Qizhi Jiangtang capsule (2.24 g•kg⁻¹), the wound was significantly reduced on day 6 and day 10 of wound formation; inflammation reaction on ulcer surface was significantly reduce; Qizhi Jiangtang capsule can increase VEGF expression in the wound tissues of diabetic rats, and inhibit ERK phosphorylation. It can be concluded that Qizhi Jiangtang capsule can promote skin ulcer healing for diabetes rats, and its mechanism may be related to regulating the expression of VEGA and p-ERK proteins.

Efficient assembly of oligomannosides using the hydrophobically assisted switching phase method.

The hydrophobically assisted switching phase (HASP) method was applied in the assembly of oligomannosides. A new mannosyl donor with high reactivity was selected after a series of optimization studies, which was suitable for the synthesis of oligomannosides via the HASP method. The practicability of the HASP method towards the synthesis of branched oligosaccharides was explored and two branched penta-mannosides were assembled efficiently.

Myricitrin attenuates endothelial cell apoptosis to prevent atherosclerosis: An insight into PI3K/Akt activation and STAT3 signaling pathways.

Blood vessel endothelial dysfunction induced by oxidized low-density lipoprotein (ox-LDL) has been implicated in the pathogenesis of atherosclerosis and vasculopathy. The ox-LDL-elicited reactive oxygen species (ROS) release has been assumed to serve a critical function in endothelial damage. Myricitrin (from Myrica cerifera) is a natural antioxidant that has strong anti-oxidative, anti-inflammatory, and anti-nociceptive activities. However, the protective effect of myricitrin on ROS-induced endothelial cell injury and its related molecular mechanisms have never been investigated. This study demonstrates that myricitrin can inhibit ox-LDL-induced endothelial apoptosis and prevent plaque formation at an early stage in an atherosclerotic mouse model. The administration of myricitrin in vivo decreases the thickness of the vascular wall in the aortic arch of ApoE-/- mice. In vitro study shows that ox-LDL-induced human umbilical vein endothelial cell apoptosis can be reduced upon receiving myricitrin pre-treatment. Treatment with myricitrin significantly attenuated ox-LDL-induced endothelial cell apoptosis by inhibiting LOX-1 expression and by increasing the activation of the STAT3 and PI3K/Akt/eNOS signaling pathways. At the same time, our result demonstrates that myricitrin treatment optimizes the balance of pro/anti-apoptosis proteins, including Bax, Bad, XIAP, cIAP-2, and survivin. Our study suggests that myricitrin treatment can effectively protect cells from ox-LDL-induced endothelial cell apoptosis, which results in reduced atherosclerotic plaque formation. This result indicates that myricitrin can be used as a drug candidate for the treatment of cardiovascular diseases.

Elatoside C protects the heart from ischaemia/reperfusion injury through the modulation of oxidative stress and intracellular Ca²âº homeostasis.

BACKGROUND: We have previously shown that Elatoside C reduces cardiomyocyte apoptosis during ischaemia/reperfusion (I/R). Here, we investigated whether Elatoside C improves heart function in isolated rat hearts subjected to I/R and elucidated the potential mechanisms involved in Elatoside C-induced protection. METHODS AND RESULTS: Isolated rat hearts were subjected to global ischaemia followed by reperfusion in the absence or presence of Elatoside C. We found that Elatoside C significantly attenuated cardiac dysfunction and depressed oxidative stress induced by I/R. Consistently, Elatoside C prevented I/R-induced mitochondrial dysfunction, which was evident by the inhibition of mitochondrial ROS production, mitochondrial permeability transition pore (mPTP) opening, cytochrome c release from the mitochondria and Bax translocation. Moreover, Elatoside C improved abnormal calcium handling during I/R, including increasing sarcoplasmic reticulum Ca(2+) ATPase (SERCA2) activity, alleviating [Ca(2+)]ER depletion, and reducing the expression levels of ER stress protein markers. All of these protective effects of Elatoside C were partially abolished by the PI3K/Akt inhibitor LY294002, ERK1/2 inhibitor PD98059, and JAK2/STAT3 inhibitor AG490. Further assessment in isolated cardiomyocytes showed that Elatoside C maintained the Ca(2+) transients and cell shortening against I/R. CONCLUSIONS: Elatoside C protects against cardiac injury during I/R by attenuating oxidative stress and [Ca(2+)]i overload through the activation of both the reperfusion injury salvage kinase (RISK) pathway (including PI3K/Akt and ERK1/2) and the survivor activating factor enhancement (SAFE) pathway (including JAK2/STAT3) and, subsequently, inhibiting the opening of mPTPs.

Evaluation of hypoglycemic efficacy of tangningtongluo formula, a traditional Chinese Miao medicine, in two rodent animal models.

Traditional Chinese medicines largely lack adequate and scientifically rigorous evidence regarding efficacy and functional mechanisms. The present study was aimed to confirm the hypoglycemic effect of Tangningtongluo (TNTL) formula, a traditional Chinese Miao medicine, in two animal models: high-fat diet and streptozotocin- (STZ-) induced diabetic rats and C57BL/KsJ-db/db diabetic mice. After 4 weeks, TNTL intervention in STZ-induced diabetic rats yielded in significant improvement on the glucose tolerance test. Moreover, the islet histopathology showed that oral TNTL reduced the severity of islet necrosis in pancreases tissue. Compared with diabetic controls, a 12-week TNTL treatment regimen (dosages = 0.9, 1.8, and 3.6 g/kg) in db/db mice significantly decreased fasting glucose and HbA1c. Additionally, oral glucose tolerance in TNTL-treated mice improved significantly, compared with diabetic mice receiving metformin. Finally, tissue histopathology and biochemical index evaluations revealed significant improvement in TNTL-treated mice. Taken together, our results show that TNTL exerted a strong hypoglycemic effect in two diabetic rodent animal models, preserving ß-cells in the pancreas islet and reducing the risk of diabetic retinopathy and nephropathy.

Elatoside C protects against hypoxia/reoxygenation-induced apoptosis in H9c2 cardiomyocytes through the reduction of endoplasmic reticulum stress partially depending on STAT3 activation.

Endoplasmic reticulum (ER) stress-induced apoptosis has been suggested to contribute to myocardial ischemia-reperfusion (I/R) injury. Elatoside C is one of the major triterpenoid compounds isolated from Aralia elata that is known to be cardioprotective. However, its effects on I/R injury to cardiac myocytes have not been clarified. This study aimed to investigate the possible protective effect of Elatoside C against hypoxia/reoxygenation (H/R)-induced H9c2 cardiomyocyte injury and its underlying mechanisms. H9c2 cardiomyocytes were subjected to H/R in the presence of Elatoside C. Our results showed that Elatoside C (25 µM) treatment provided significant protection against H/R-induced cell death, as evidenced by improved cell viability, maintained mitochondrial membrane potential, diminished mitochondrial ROS, and reduced apoptotic cardiomyocytes (P < 0.05). These changes were associated with the inhibition of ER stress-associated apoptosis markers (GRP78, CHOP, Caspase-12 and JNK), as well as the increased phosphorylation of STAT3 and an increased Bcl2/Bax ratio. Moreover, these effects of Elatoside C were prevented by the STAT3 inhibitor Stattic. Taken together, these results suggested that Elatoside C can alleviate H/R-induced cardiomyocyte apoptosis most likely by activating the STAT3 pathways and reducing ER stress-associated apoptosis.

Adaptable synthesis of C-lactosyl glycoclusters and their binding properties with galectin-3.

We report here the syntheses of mono- to tetravalent glycoclusters containing 1-methylene-C-ß-lactose. The 1-methylene-C-ß-lactose moiety has been synthesized from octa-acetyl-ß-lactose using the key carbonyl insertion reaction and linked to a series of alkynlated scaffolds via CuAAC reaction to afford mono- to tetravalent glycoclusters. The binding affinities of the final products to galectin-3 were found in the range of 10-100 µM.

Aconitine-induced Ca2+ overload causes arrhythmia and triggers apoptosis through p38 MAPK signaling pathway in rats.

Aconitine is a major bioactive diterpenoid alkaloid with high content derived from herbal aconitum plants. Emerging evidence indicates that voltage-dependent Na(+) channels have pivotal roles in the cardiotoxicity of aconitine. However, no reports are available on the role of Ca(2+) in aconitine poisoning. In this study, we explored the importance of pathological Ca(2+) signaling in aconitine poisoning in vitro and in vivo. We found that Ca(2+) overload lead to accelerated beating rhythm in adult rat ventricular myocytes and caused arrhythmia in conscious freely moving rats. To investigate effects of aconitine on myocardial injury, we performed cytotoxicity assay in neonatal rat ventricular myocytes (NRVMs), as well as measured lactate dehydrogenase level in the culture medium of NRVMs and activities of serum cardiac enzymes in rats. The results showed that aconitine resulted in myocardial injury and reduced NRVMs viability dose-dependently. To confirm the pro-apoptotic effects, we performed flow cytometric detection, cardiac histology, transmission electron microscopy and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay. The results showed that aconitine stimulated apoptosis time-dependently. The expression analysis of Ca(2+) handling proteins demonstrated that aconitine promoted Ca(2+) overload through the expression regulation of Ca(2+) handling proteins. The expression analysis of apoptosis-related proteins revealed that pro-apoptotic protein expression was upregulated, and anti-apoptotic protein BCL-2 expression was downregulated. Furthermore, increased phosphorylation of MAPK family members, especially the P-P38/P38 ratio was found in cardiac tissues. Hence, our results suggest that aconitine significantly aggravates Ca(2+) overload and causes arrhythmia and finally promotes apoptotic development via phosphorylation of P38 mitogen-activated protein kinase.

P90RSK and Nrf2 Activation via MEK1/2-ERK1/2 Pathways Mediated by Notoginsenoside R2 to Prevent 6-Hydroxydopamine-Induced Apoptotic Death in SH-SY5Y Cells.

6-Hydroxydopamine (6-OHDA) is known to contribute to neuronal death in Parkinson's disease. In this study, we found that the preincubation of SH-SY5Y cells for 24 h with 20 µ M notoginsenoside R2 (NGR2), which is a newly isolated notoginsenoside from Panax notoginseng, showed neuroprotective effects against 6-OHDA-induced oxidative stress and apoptosis. NGR2 incubation successively resulted in the activation of P90RSK, inactivation of BAD, and inhibition of 6-OHDA-induced mitochondrial membrane depolarization, thus preventing the mitochondrial apoptosis pathway. NGR2 incubation also led to the activation of Nrf2 and subsequent activity enhancement of phase II detoxifying enzymes, thus suppressing 6-OHDA-induced oxidative stress, and these effects could be removed by Nrf2 siRNA. We also found that the upstream activators of P90RSK and Nrf2 were the MEK1/2-ERK1/2 pathways but not the JNK, P38, or PI3K/Akt pathways. Interestingly, NGR2 incubation could also activate MEK1/2 and ERK1/2. Most importantly, NGR2-mediated P90RSK and Nrf2 activation, respective downstream target activation, and neuroprotection were reversed by the genetic silencing of MEK1/2 and ERK1/2 by using siRNA and PD98059 application. These results suggested that the neuroprotection elicited by NGR2 against 6-OHDA-induced neurotoxicity was associated with NGR2-mediated P90RSK and Nrf2 activation through MEK1/2-ERK1/2 pathways.

[Protect effects and the underlying mechanisms of myricitrin against vascular endothelial cells apoptosis induced by oxidative stress].

This study is to report the study of protective effects of myricitrin against oxidative stress-induced apoptosis of vascular endothelial cells and the investigation of the possible mechanisms of action of myricitrin. The model of H2O2-induced apoptosis of vascular endothelial cells was used to determine the protective effects of myricitrin. The levels of LDH, MDA and the activities of SOD, NO were measured using the respective kits. The H2O2-induced apoptosis of vascular endothelial cells was detected using MTT reduction, TUNEL assay, JC-1 and ROS staining. The activation of Caspase-3 was also measured by fluorometry. The expression of apoptosis-related proteins was determined with Western blotting assay. Myricitrin had significant protective effects against H2O2-induced apoptosis of vascular endothelial cells in a time- and dose-dependent manner. The results show that myricitrin could attenuate H2O2-induced decrease in the activities of SOD (P < 0.01). Myricitrin could decrease the levels of LDH, MDA and increase cell viability and the mitochondrial membrane potential (P < 0.01). Myricitrin had protective effects in a dose-dependent manner between 32 micromol x L(-1) to 64 micromol x L(-1). Myricitrin pretreatment could attenuate H2O2-induced increase of p-ERK. Moreover, myricitrin pretreatment could up-regulate the expression of the anti-apoptotic protein Bcl-2, down-regulate the expression of the pro-apoptotic protein Bax, and decrease the expression of Caspase-3, 9. In conclusion, myricitrin had significant protective effects against H2O2-induced apoptosis of vascular endothelial cells. Myricitrin can enhance the activities of anti-oxidative enzymes and decrease the production of free radicals. The possible mechanisms of action of myricitrin are due to myricitrin-mediated inhibition of phosphorylation of the apoptosis signaling pathways-related kinase ERK, up-regulation of the expression of the anti-apoptotic protein, and down-regulation of the expression of the pro-apoptotic protein.