AIM: To demonstrate the mechanisms underlying cardioprotection induced by ischemic postconditioning(I-postC) via studying the alteration of calreticulin(CRT)/calcineurin(CaN) signaling pathway in rat heart subjected to ischemia/reperfusion(I/R).METHODS: The model of myocardial I/R injury in vivo was made by occluding the left anterior descending artery for 45 min followed by 24 h of reperfusion in Wistar rats.Hemodynamics and activity of lactate dehydrogenase(LDH) and creatine kinase-MB(CK-MB) in plasma were measured.Myocardial infarct size was measured by 2,3,5-triphenyltetrazolium chloride(TTC) staining and cardiomyocyte apoptosis was detected using in situ TDT-mediated dUTP nick end labeling(TUNEL).The activity of CaN,the expressions of CaN and CRT in myocardium were detected by enzyme reaction phosphorus measurement and Western blotting analysis,respectively.RESULTS: Cyclosporin A,the inhibitor of CaN,limited significantly myocardial infarct size and cardiomyocyte apoptosis induced by I/R,but had no significant effect on cardiac function.I-postC ameliorated significantly the cardiac dysfunction induced by I/R.Compared with those in I/R group,the myocardial infarct size,the LDH and CK-MB activities in plasma and the cardiomyocyte apoptotic index were significantly reduced in I-postC group.In addition,I/R-induced upregulation of CaN activity,CaN and CRT expression were relieved by I-postC.No significant difference was found between I-postC and ischemic preconditioning groups.I-postC had stronger protective effect on the reperfused heart compared with cyclosporin A.CONCLUSION: The findings indicate that I-postC protects myocardium against I/R injury,at least in part,via inhibiting the CRT/CaN signaling pathway.

AIM:To investigate the ameliorative effect of ischemic postconditioning (I-postC) on pia mater microcirculation in rats subjected to cerebral ischemia reperfusion (I/R) and its mechanisms. METHODS:Thirty-two male Wistar rats were randomly divided into sham,I/R,I-postC,and ischemic preconditioning (IPC) groups. The global cerebral I/R injury was induced by shunting carotid artery in rats. Pia mater microcirculation and cerebral microcirculatory perfusion were measured after reperfusion. The content of soluble intercellular adhesion molecule-1 (sICAM-1) in plasma was detected using enzyme linked-immunosorbent assay (ELISA). Myeloperoxidase (MPO),malondialdehyde (MDA),and superoxide dismutase (SOD) in cerebral tissue were detected. The expressions of vascular endothelial cell cadherin (VE-cadherin) and NF-?B p65 in cerebral tissue were assayed by Western blotting. RESULTS:(1) The disturbance of the blood flow in microvessel induced by I/R was improved significantly by I-postC. In addition,I-postC alleviated significantly the decrease in diameters of microvesseles,cerebral microcirculatory perfusion and cerebral VE-cadherin content induced by I/R (P

Atherosclerosis is a multifactorial process associated with endothelial cell injury and dysfunction , inflammation, oxidative stress, cell proliferation, angiogenesis and so on , all of which play a crucial role in atherosclerosis . Wnt/β-catenin signaling pathway is highly conservative in the development of body , abnormal activation of which is related to types of diseases including cancer .Accumulating studies have shown that Wnt/β-catenin signaling pathway is involved in inflammation, oxidative stress and so on .This article would make a review about the role of Wnt/β-catenin signaling path-way in atherosclerosis based on the pathogenic mechanisms underlying atherosclerosis as mentioned above .

AIM: To investigate the ameliorative effect of water extract of propolis (WEP) preconditioning on mesenteric microcirculation of rats subjected to small intestinal ischemia reperfusion (I/R). METHODS: Thirty-two male Wistar rats were randomly divided into sham, I/R and WEP (100, 200 mg/kg) preconditioning groups. Model of small intestinal I/R injury was made by clamping super mesenteric artery for 45 min followed by 120 min of reperfusion in rats. Mesenteric microcirculation was detected at the end of reperfusion. The degree of small intestinal injury was The content of soluble intercellular adhesion molecule-1 (sICAM-1) in plasma and myeloperoxidase (MPO) activity in intestinal tissue were detected using enzyme linked-immuno-sorbent assay (ELISA) and spectrophotometer, respectively. RESULTS: (1) WEP preconditioning alleviated significantly the pathologic lesion in small intestine, and wet/dry ratio, compared to those in I/R group (P<0.01). (2) The disturbance of the blood flow in microvessel induced by I/R was improved significantly by WEP. In addition, WEP preconditioning alleviated significantly the decrease in diameters of microvessels and microcirculatory blood velocity (P<0.05 vs I/R group) and inhibited the adherence of leukocytes to venule (P<0.01 vs I/R group) in a dose-dependent manner. SICAM-1 content in plasma and MPO activity in intestinal tissue were decreased in WEP preconditioning group, compared to those in I/R group (P<0.05 or P<0.01). CONCLUSION: WEP preconditioning ameliorates mesenteric microcirculation of rats subjected to small intestinal I/R through suppressing the activation of polymorphonuclear neutrophils mediated by ICAM-1.

[ ABSTRACT] AIM:To investigate the effect of oxidized low-density lipoprotein ( ox-LDL) on autophagy in mac-rophages and the underlying molecular mechanisms.METHODS:RAW264.7 macrophages were pretreated with 2 mg/L anti-CD36 monoclonal antibody (anti-CD36 mAb), 5 μmol/L diphenyleneiodonium (DPI), 3 mmol/L 3-methyladenine (3-MA) or 1μmol/L rapamycin for 1 h and then treated with ox-LDL (100 mg/L) for 12 h.The viability of the cells was measured by MTT assay.The activities of lactic dehydrogenase ( LDH) in the medium and nicotinamide adenine dinucleoti-de phosphate ( NADPH) oxidase, superoxide dismutase ( SOD) in the cells as well as the levels of intracellular reactive ox-ygen species ( ROS) and malondialdehyde ( MDA) were determined to characterize the membrane integrity and the oxida-tive stress, respectively.The protein levels of beclin-1 and microtubule-associated protein 1 light chain 3-II ( LC3-II) , 2 important molecular markers of autophagy, were examined by Western blotting.RESULTS:ox-LDL induced autophagy in
RAW264.7 macrophages as assessed by upregulation of beclin-1 and LC3-II.Similar to 3-MA, an autophagy inhibitor, an-ti-CD36 mAb significantly inhibited the ox-LDL-induced upregulation of beclin-1 and LC3-II.Anti-CD36 mAb suppressed the ox-LDL-induced oxidative stress as revealed by decreased NADPH oxidase activation, ROS and MDA generation as well as increased SOD activity.Similar results were observed in the cells pretreated with DPI, a NADPH oxidase inhibitor.Mo-reover, DPI significantly inhibited the ox-LDL-induced upregulation of beclin-1 and LC3-II.Inaddition, the decrease in the cell viability and increase in LDH release induced by ox-LDL were promoted by 3-MA and blocked by rapamycin ( an auto-phagy inducer).CONCLUSION: ox-LDL induces autophagy in RAW264.7 macrophages, which may be involved in CD36-mediated ox-LDL uptake and subsequent activation of oxidative stress, and moderate activation of autophagy may pro-tect macrophages from ox-LDL-induced injury.

AIM:To investigate the effect of quercetin on the biological functions of rat bone marrow-derived endothelial progenitor cells (EPCs) and its potential mechanisms.METHODS:The bone marrow-derived mononuclear cells of Sprague-Dawley rats were isolated by density gradient centrifugation.The differentiated EPCs were cultured specially and stained with DiI-Ac-LDL and FITC-UEA-1.CD133+ and FLK-1+ were detected on the cell surfaces.After 14 d, the EPCs were incubated with a PI3K inhibitor BYL719 (3 μmol/L) and an ERK inhibitor FR180204 (15 μmol/L).After incubation of the inhibitors for 2 h, the cells were treated with quercetin at different concentrations (0, 10, 20, 40, 80 and 100 μmol/L).MTT assay and Transwell assay were used to detect cell viability and the number of migratory cells.The protein levels of AKT, eNOS, ERK and their phosphorylated status were determined by Western blot.RESULTS:Quercetin enhanced the viability and migration of the EPCs at a dose-dependent manner.However, the PI3K inhibitor BYL719 suppressed the QUE-induced cell viability and migration.Moreover, ERK inhibitor FR180204 exerted the similar inhibitory effect on the cell viability but had no effect on cell migration.Quercetin activated the phosphorylation of AKT, eNOS and ERK.On the other hand, BYL719 was observed to inhibit the phosphorylation of AKT and ERK.FR180204, however, was showed to inhibit the phosphorylation of ERK only.On the contrast, the stimulatory effects that quercetin exerted on the expression of eNOS and its phosphorylation were suppressed by BYL719 and FR180204.CONCLUSION:Quercetin stimulates the viability and migration of EPCs via PI3K/AKT/eNOS and ERK/eNOS signaling pathway, which would be beneficial for cardiovascular health.

[ ABSTRACT] AIM: To investigate the protective effect of autophagy on oxidized low density lipoprotein ( ox-LDL)-induced macrophage apoptosis and the underlying molecular mechanisms .METHODS:The RAW264.7 macropha-ges were pretreated with 3 mmol/L 3-methyladenine (3-MA), 1 μmol/L rapamycin (Rap) or 4 mmol/L 4-phenylbutyric acid ( PBA) respectively for 1 h and then treated with ox-LDL (100 mg/L) for 12 h.The cell viability and apoptosis were determined by MTT assay and flow cytometry with Annexin V-FITC/PI staining, respectively.The activities of lactate de-hydrogenase ( LDH) in the medium and caspase-3 in the cells were determined by detection kits .The protein levels of bec-lin-1 (a molecular marker of autophagy ), glucose-regulated protein 78 (GRP78, an endoplasmic reticulum stress marker) and C/EBP homologous protein ( CHOP, a key-signaling component of endoplasmic reticulum stress-induced apoptosis ) were examined by Western blot .Microtubule-associated protein 1 light chain 3 (LC3, another molecular marker of autoph-agy) was observed under laser scanning confocal microscope .RESULTS: Treatment of the RAW264.7 macrophages with ox-LDL at 100 mg/L for 12 h resulted in significant decrease in cell viability , and dramatic elevation in LDH leakage , cell apoptosis and caspase-3 activity, which were promoted by 3-MA (an autophagy inhibitor) and inhibited by Rap (an autoph-agy inducer ) .ox-LDL induced autophagy in the macrophages as assessed by beclin-1 upregulation and frequent granulation of LC3, which were inhibited by 3-MA and promoted by Rap.Interestingly, 3-MA enhanced, while Rap blocked, the CHOP upregulation induced by ox-LDL.Moreover , PBA ( endoplasmic reticulum stress inhibitor ) significantly inhibited ox-LDL-induced GRP78 upregulation and autophagy as determined by the attenuation of beclin-1 upregulation and frequent granula-tion of LC3.CONCLUSION: Endoplasmic reticulum stress mediates ox-LDL-induced autophagy in macrophages , and moderates activation of autophagy may protect macrophages from ox-LDL-induced apoptosis by inhibiting CHOP expression .

[ABSTRACT]AIM:ToinvestigatetheeffectofD4F,anapolipoproteinA-Imimeticpeptide,onoxidizedlow-density lipoprotein ( ox-LDL)-induced macrophage apoptosis and activation of caspase-12, a key molecule in endoplasmic reticulum stress ( ERS )-associated apoptotic pathway, and to elucidate the underlying molecular mechanisms. METHODS:RAW264.7 macrophages were pretreated with D4F (12.5, 25 and 50 mg/L), 4-phenylbutyric acid (PBA, 5 mmol/L) or diphenyleneiodonium ( DPI, 5 μmol/L) for 1 h and then treated with ox-LDL (100 mg/L) or tunicamycin ( TM, 4 mg/L) for 24 h.The cell viability and apoptosis were determined by MTT assay and TUNEL detection, respective-ly.The levels of malondialdehyde ( MDA) and reactive oxygen species ( ROS) in the cells and the activities of superoxide dismutase ( SOD) and nicotinamide adenine dinucleotide phosphate ( NADPH) oxidase were determined.The protein level of caspase-12 was examined by Western blot analysis.RESULTS: Similar to the ERS inhibitor PBA, D4F protected RAW264.7 macrophages from ox-LDL or TM ( an ERS inducer)-induced decrease in the viability and increase in apoptotic rate in a dose-dependent manner.Like DPI (an oxidative stress inhibitor), D4F significantly inhibited ox-LDL-induced ox-idative stress, as expressed by the decreased generation of ROS and MDA ( P<0.01) , the increased activity of SOD and the decreased activity of NADPH oxidase (P<0.05).Moreover, similar to PBA and DPI, D4F significantly suppressed ox-LDL-induced activation of caspase-12 in a concentration-dependent manner ( P<0.05) .Furthermore, D4F also inhibi-ted the caspase-12 activation induced by TM (P<0.05).CONCLUSION: D4F inhibits macrophage apoptosis induced by ox-LDL, and the mechanism is at least partially by reducing oxidative stress and inhibiting the activation of caspase-12.

AIM:To investigate the inhibitory effect of ethanol extract of propolis (EEP) on oxidized low-den-sity lipoprotein ( ox-LDL )-induced macrophage apoptosis and the underlying molecular mechanisms . METHODS:RAW264.7 macrophages were pretreated with EEP (7.5, 15 and 30 mg/L), 4-phenylbutyric acid (PBA, 5 mmol/L) or diphenyleneiodonium ( DPI, 5μmol/L) for 1 h and then treated with ox-LDL (100 mg/L) or tunicamycin ( TM, 4 mg/L) for 24 h.The cell viability and apoptosis were determined by MTT assay and Annexin V-FITC apoptosis detection kit , re-spectively.The activity of superoxide dismutase (SOD), and the levels of reactive oxygen species (ROS) and malondial-dehyde (MDA) in the cells were measured.The protein levels of caspase-12, a proapoptotic molecule under endoplasmic reticulum stress ( ERS) , were examined by Western blot analysis .RESULTS:Like PBA ( an ERS inhibitor ) , EEP pro-tected RAW264.7 macrophages from ox-LDL-induced injury in a dose-dependent manner , as assessed by the increased cell viability and the decreased apoptotic rate .The decrease in cell viability and increase in apoptotic rate induced by TM , an ERS inducer, were also attenuated by EEP .Moreover, EEP suppressed ox-LDL-induced oxidative stress as revealed by the decreased generation of ROS and MDA as well as elevated SOD activity , which were similar to DPI , an oxidative stress in-hibitor.Furthermore, EEP significantly suppressed ox-LDL-or TM-induced activation of caspase-12.Similar results were observed in the cells pretreated with PBA or DPI and then treated with ox-LDL.CONCLUSION: EEP may protect RAW264.7 macrophages from ox-LDL-induced apoptosis and the mechanism is at least partially involved in the ability of EEP to suppress oxidative stress and subsequent activation of caspase -12.

AIM:To investigate the inhibitory effect of apolipoprotein A-I mimetic peptide D-4F on the scaven-ger receptor A1 ( SR-A1 ) in macrophage-derived foam cells induced by oxidized low-density lipoprotein ( ox-LDL ) . METHODS:RAW264.7 cells were pretreated with different concentrations (12.5, 25 and 50 mg/L) of D-4F or 50 mg/L inactive control peptide scrambled D-4F (sD-4F) for 1 h or endoplasmic reticulum stress (ERS) inhibitor 4-phenylbutyr-ic acid (5 mmol/L) for 30 min, followed by the treatment with 100 mg/L ox-LDL for 12 h.In addition, the cells were pre-treated with 50 mg/L D-4F or sD-4F for 1 h, and then stimulated with 2 mg/L tunicamycin (TM;an ERS inducer), for 4 h.The viability of the cells was measured by MTT assay, and the content of intracellular total cholesterol ( TC) was meas-ured by a tissue/cell TC assay.The protein and mRNA levels of SR-A1 and glucose-regulated protein 78 (GRP78) were analyzed by Western blotting and quantitative real-time PCR, respectively.The fluorescence intensity of DiI-ox-LDL in the cells was detected by a multifunctional microplate reader.RESULTS:D-4F significantly reduced ox-LDL-induced macro-phage injury and intracellular cholesterol accumulation, and attenuated the ox-LDL-induced expression of SRA1 and GRP78 in a dose-dependent manner.Additionally, D-4F significantly inhibited the TM-induced protein expression of SR-A1 and GRP78, and attenuated the uptake of ox-LDL by macrophages.CONCLUSION: D-4F reduces ox-LDL-induced macro-phage cholesterol accumulation and injury by inhibiting SR-A1 expression.The mechanism may be related to the inhibition of ERS signaling pathway mediated by GRP78.