Effects of bortezomib-based therapy on hemostasis system and circulating microparticles in multiple myeloma patients

AIM：To investigate the changes of hemostasis, thrombosis and total microparticles (TMPs) in multiple myeloma (MM) patients receiving bortezomib-based induction therapy (bortezomib+adriamycin+dexamethasone, PAD). METHODS：The levels of TMPs were detected by flow cytometry in 38 newly diagnosed MM patients and 30 healthy people. The changes of the platelet, coagulation, anticoagulation, fibrinolytic activation and TMPs in the MM patients before and after PAD teatment were also studied.RESULTS：Before treatment, the values of FVIII:C and vWF:Rco in MM patient were elevated ［(152.89±31.14)% and (165.69±38.43)%］, the activation of platelet aggregation was inhibited ［(63.76±21.36)%］, and the PAI level increased ［3.98(1.63)U/mL］. Compared with the healthy people, higher concentration of TMPs was observed in MM patients ［(640.65±214.22)/μL vs (134.29±63.09)/μL, P<0.01］, and the level of TMPs was positively correlated with serum β2-MG (r=0.672, P<0.01).After PAD therapy, platelet aggregation activation was restored ［(77.83±15.62)%, P=0.01］, and PAI level decreased ［0.88(1.38)U/mL, P<0.01］. The level of TMPs also decreased, after 3 cycles of PAD, to the value of (184.25±93.35)/μL. CONCLUSION：MM patients were characterized by impaired platelet, coagulation and fibrinolysis functions, and increased level of TMPs. PAD restored platelet function, decreased the levels of PAI and TMPs, which might partially explain the low incidence of thrombosis in the MM patients receiving bortezomib-based treatment.     

Protective effect of ethyl pyruvate on brain tissues in neonatal rats with hypoxic-ischemic brain damage

AIM：To study the effects of ethyl pyruvate (EP) on brain tissues in neonatal rats with hypoxic-ischemic brain damage (HIBD) and its underlying mechanisms. METHODS：A total of 165 seven-day-old Sprague-Dawley (SD) rats were randomly divided into 3 groups：sham operation group (n=43), HIBD group (n=61) and HIBD+EP group (n=61). The rats in HIBD+EP group were intraperitoneally injected with EP (50 mg/kg) 30 min before operation, and once a day after surgery. Superoxide dismutase (SOD) activity and malondialdehyde (MDA) content in brain homogenate, water content of brain and apoptotic cells in cortex were detected 3 days later. Ischemic and non-ischemic brain tissues were weighed to assess the extent of brain atrophy 14 days later. RESULTS：Higher level of SOD ［(125.78±18.35)×103 U/(g protein)］ and lower level of MDA ［(4.42±1.04) μmol/(g protein)］ in HIBD+EP group than that in HIBD group ［(97.84±15.50)×103 U/(g protein) and (6.02±0.89) μmol/(g protein), respectively］ was observed (P<0.05)．In addition, the water content of ischemic hemisphere was significantly higher than that of non-ischemic one in HIBD group (P<0.05), and was indistinguishable from that of non-ischemic one after EP treatment (P>0.05), indicating the protective effect of EP against brain edema. The apoptotic cells in cortex and hippocampus in HIBD+EP group ［(96.63±10.08)/field and (41.91±9.96)/field, respectively］ were obviously decreased compared with HIBD group ［(111.54±1.64)/field and (51.73±1.77)/field, respectively］, but still higher than those in sham operation group (P<0.05). The atrophy ratio of ischemic hemisphere in HIBD+EP group was (13.25±5.19)%, significantly lower than that in HIBD group ［(20.32±5.10)%, P<0.05］. CONCLUSION：Ethyl pyruvate is neuroprotective against HIBD in neonatal rats via increasing SOD level, decreasing MDA level, attenuating brain edema, decreasing apoptotic cells in cortex and alleviating atrophy of hypoxic-ischemic hemisphere.     

Atorvastatin inhibits atherogenesis by RXRα-mediated depressing oxidative stress in STZ-induced diabetic ApoE-/- mice with fat-rich diet

AIM: To explore the effects of atorvastatin (Atorv) on atherosclerosis in streptozotocin (STZ)-induced diabetic apolipoprotein E knockout (ApoE-/-) mice with fat-rich diet and the possible mechanism. METHODS：C57 mice served as control. ApoE-/- mice (n=34) fed with high-fat diet were randomly divided into ApoE-/- group, STZ-ApoE-/- group and STZ-ApoE-/-+Atorv group. Intraperitoneal injection of streptozotocin was performed to create diabetic animal model. Blood glucose was determined by glucose oxidase method. Blood lipid levels were detected by enzymic method or selective homogeneous method. The plaque area in the thoracic aorta was measured by HE staining. The protein level of nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase subunit gp91phox in the thoracic aorta was determined by Western blotting. The levels of reactive oxygen species (ROS) in blood and thoracic aorta homogenates were detected by Fenton reaction and Griess reagent. Human umbilical vein endothelial cells (HUVECs) were isolated from healthy umbilical cords by collagenase I and cultured. ROS production was detected by flow cytometry. NADPH oxidase activity was measured using lucigenin assay.Effects of retinoid X receptor α (RXRα) on inhibition of oxidative stress by atorvastatin were evaluated by RNA interference and plasmid transfection. RESULTS：(1) Compared with C57 group, the plaque areas of the thoracic aorta in ApoE-/- group were increased. No difference of the fasting glucose between the 2 groups was observed. The levels of triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), thoracic aorta gp91phox protein and ROS in blood and thoracic aorta homogenates were higher in ApoE-/- group than those in C57 group. (2) Compared with ApoE-/- group, the plaque areas of the thoracic aorta in STZ-ApoE-/- group were further enlarged ［(314.13±35.72) μm2 vs (215.88±34.19) μm2, P<0.05］. The levels of blood glucose, TG, TC and LDL-C, thoracic aorta gp91phox protein and ROS in blood and thoracic aorta homogenates were higher in STZ-ApoE-/- group than those in ApoE-/- group (P<0.05). (3) Compared with STZ-ApoE-/- group, the plaque areas of the thoracic aorta in STZ-ApoE-/- +Atorv group were reduced ［(217.47±24.56） μm2 vs （314.13±35.72） μm2, P<0.05］. The levels of blood glucose, LDL-C, TC, HDL-C and TG showed no significant difference between the 2 groups. Thoracic aorta gp91phox protein level and ROS production in blood and thoracic aorta homogenates were lower in STZ-ApoE-/- +Atorv group than those in STZ-ApoE-/- group (P<0.05). (4) High glucose-induced increases in NADPH oxidase activity and gp91phox expression were significantly inhibited by atorvastatin (10-6 mol/L) in HUVECs. The inhibitory effects of atorvastatin on high glucose-induced ROS production and NADPH oxidase activation were largely impaired when the cells were transfected with RXRα siRNA. However, the effect of atorvastatin was significantly strengthened when RXRα was over-expressed in the HUVECs transfected with RXRα plasmid. CONCLUSION：Atorvastatin inhibits atherogenesis by depressing high glucose-induced oxidative stress in diabetic ApoE-/- mice with fat-rich diet. The anti-oxidative stress effect of atorvastatin is mediated by RXRα.     

Aldolase A level in malignant pleural effusion and its effects on proliferation,migration and invasion of human lung adenocarcinoma cells

AIM：
To investigate the levels of aldolase A (ALDOA), carcinoembryonic antigen (CEA) and lactate dehydrogenase (LDH) in malignant pleural effusion (MPE) from patients with lung cancer and tuberculous pleural effusion (TBPE) from patients with tuberculous pleurisy, and to explore the effects of ALDOA on the proliferation, migration and invasion of human lung adenocarcinoma A549 cells. METHODS：Pleural effusion samples including 65 cases of MPE and 35 cases of TBPE were collected, and the levels of ALDOA, CEA and LDH were detected by ELISA and chemiluminescence assay. After A549 cells were treated with different concentrations of ALDOA, the proliferation, migration and invasion of the cells were investigated by MTT assay, scratch test, Matrigel assay and Transwell invasion assay. RESULTS：The levels of ALDOA, CEA and LDH in MPE were (46.8±21.4) μg/L, (82.2±56.6) μg/L and (755.8±382.5) U/L, respectively, which were significantly higher than those in TBPE ［(23.9±17.2) μg/L, (12.6±9.7) μg/L and (388.4±163.9) U/L, respectively; P<0.01］. The concentration of ALDOA in MPE from adenocarcinoma patients ［(71.7±32.1) μg/L］ was significantly higher than that in MPE from squamous-cell carcinoma patients ［(21.3±14.6) μg/L, P<0.05］. The concentrations of ALDOA in MPE and TBPE were positively correlated with the concentrations of CEA and LDH (P<0.01 or P<0.05). ALDOA enhanced the proliferation, migration and invasion of A549 cells in a concentration-dependent manner. CONCLUSION：The expression level of ALDOA in MPE is significantly higher than that in TBPE, especially in MPE from lung adenocarcinoma patients. There are highly positive correlations between ALDOA and CEA, ALDOA and LDH in pleural effusion. ALDOA concentration-dependently promotes the proliferation, migration and invasion of A549 cells.     

Inhibitory effect of high-dose Xuezhikang on inflammatory response induced by percutaneous coronary intervention in patients with unstable angina

AIM: To study the inhibitory effect of high-dose Xuezhikang,administered before percutaneous coronary intervention (PCI) on inflammatory response induced by PCI in patients with unstable angina (UA).METHODS: All patients with UA in class Ⅲ and ⅡB according to Braunwald classification were considered for inclusion in the present study.Finally,196 patients received Xuezhikang treatment 72 h before coronary angiography and successfully performed PCI with elevated C-reactive protein (CRP) level (>3 mg/L) were randomised to 2 groups: 1.2 g/d of Xuezhikang as group A,or 2.4 g/d of Xuezhikang as group B.The levels of CRP were measured at baseline,after 3 days of therapy (before procedure) and 48 hours after PCI.The patients were followed-up for 6 months for major adverse coronary events and left ventricular ejection fraction.RESULTS: There was no significant difference in the mean CRP level among the two randomized groups (P>0.05),however,after three days of pharmacological treatment,there was significantly reduced CRP content in group A ［(5.44±1.57） mg/L vs （4.04±1.54） mg/L,P<0.05］ and in group B ［(5.42±1.36） mg/L vs （3.60±1.14） mg/L,P<0.05］ compared with admission.Measurements performed 48 hours after the procedure revealed a marked CRP level increase in group A (up to 9.22 mg/L±5.03 mg/L) and an obvious increase in groups B (up to 4.97 mg/L±1.75 mg/L,P<0.05) compared with pre-procedure.The serum level of CRP in B group was distinctly lower than that in A group before (P<0.05) and after the procedure (P<0.05),respectively.Major adverse coronary events during the 6-month clinical follow-up occurred less in group A than that in group B ［21/104 (20.2%) vs 9/92 (9.8%); patients,P<0.05］.Follow-up echocardiography revealed lower left ventricular ejection fraction in group A than that in group B (55.41%±10.93% vs 59.30%±9.99%,P<0.05).CONCLUSION: High-dose Xuezhikang therapy,administered before PCI,has better inhibition effect than low-dose on inflammatory response induced by PCI in patients with UA.Attenuation of inflammatory response may be crucial for the reduction of coronary events following invasive coronary interventions.     

Effects of peripheral-type benzodiazepine receptors in platelet membrane on patients with depression after first attack of cerebral infarction

AIM：To evaluate the changes of peripheral-type benzodiazepine receptors (PBRs) in platelet membrane in post-stroke depression (PSD) patients and to investigate the effects of PBRs on PSD. METHODS：Forty-three patients with PSD, fifty-nine patients with first-ever cerebral infarction and fifty-six healthy volunteers participated in this study. Platelet membrane in venous blood was prepared. Binding assay of the radioactive PBRs antagonist ［3H］PK11195 to platelet membrane was performed. RESULTS：A significant difference of ［3H］PK11195 binding was found among the 3 groups (P<0.01). Compared with the healthy volunteers ［(298.2±25.1） pmol/(g protein)］, a highly significant increase in ［3H］PK11195 binding was observed in platelet membrane in the patients with first attack of cerebral infarction ［(1 410.8±41.4） pmol/(g protein), P<0.01］. Compared with the patients with first attack of cerebral infarction, a significant reduction in ［3H］PK11195 binding was detected in platelet membrane in the patients with PSD ［(361.7±30.6) pmol/(g protein), P<0.01］. In the patients with PSD, no significant difference of ［3H］PK11195 binding was found between men and women (P>0.05). ［3H］PK11195 binding was related to the score of Hamilton depression rating scale (r=-0.44, P<0.01) but not to the duration of cerebral infarction (r=0.27,P>0.05). CONCLUSION:PBRs binding activity in platelet membrane decreases in the patients with PSD and affects the degree of depression.     

Effects of docosahexaenoic acid on large-conductance calcium-activated potassium channels in rat pulmonary artery smooth muscle cells

AIM：To investigate the effects of docosahexaenoic acid (DHA) on large-conductance calcium-activated potassium channels (BKCa) in rat pulmonary artery smooth muscle cells (PASMCs)．METHODS：BKCa currents in individual PASMCs were recorded by patch-clamp technique in whole-cell configuration．Calcium sparks in PASMCs caused by DHA were recorded by confocal microscopy. RESULTS：DHA activated BKCa . BKCa current densities were (30.5±6.5)pA/pF,(59.4±5.8)pA/pF, (87.2±4.3)pA/pF and (117.3±7.1) pA/pF (P<0.01) with the addition of DHA at concentrations of 0, 0.1, 1 and 10 μmol/L, respectively. Hypoxia inhibited BKCa currents in PASMCs, but this inhibition was reversed by DHA (10 μmol/L). DHA (10 μmol/L) induced an increase in ［Ca2+］i with a maximal increase rate of (71.9±4.1)%. CONCLUSION：DHA activates BKCa in rat PASMCs, leading to the vasodilation of pulmonary arteries.     

Inhibition of miR-9 expression suppresses proliferation,invasion and migration of nasopharyngeal carcinoma cells

AIM: To investigate the effects of down-regulated miR-9 expression on the proliferation, invasion and migration of nasopharyngeal carcinoma (NPC) cells. METHODS: Human NPC CNE1 and CNE2 cells were transfected with the inhibitor of miR-9 by Lipofectamine to down-regulate the expression of miR-9, and the cells transfected with an inhibitor control were also set up. The cell proliferation and cell cycle were evaluated by CCK-8 assay and flow cytometry. The cell invasion and migration abilities were detected by Transwell invasion and wound-healing assays. Immunoblotting was applied to analyze the levels of the proteins. RESULTS: Compared with control group, inhibition of miR-9 expression in the NPC cells by transfection of the miR-9 inhibitor significantly decreased the proliferation ability (P<0.05). The percentages of the cells in G0/G1 phase ［CNE2: (57.96±1.39)% vs (47.93±1.76)%, P<0.05; CNE1: (51.24±0.88)% vs (48.29±0.39)%, P<0.05］ were significantly increased. The migration distances ［CNE2: (186.50±7.94)μm vs (247.56±15.56)μm, P<0.05; CNE1: (139.06±16.73)μm vs (230.66±14.27)μm, P<0.01］ and the invasion ability of the CNE2 cells (43.00±3.17 vs 65.80±5.20, P<0.01) were also significantly inhibited. Moreover, the tumor cells transfected with the inhibitors produced lower β-catenin. CONCLUSION: Inhibition of miR-9 expression suppresses the proliferation, invasion and migration of nasopharyngeal carcinoma cells.     

Effect of renal sympathetic denervation on cardiac hypertrophy and fibrosis

AIM:To investigate the effect of renal sympathetic denervation (RDN) on cardiac hypertrophy and fibrosis and to explore the underlying mechanisms. METHODS:Male SD rats were randomly divided into 4 groups: sham, sham plus RDN, aortic constriction (AC) and AC plus RDN group (n=15 for each group). After the intervention for 8 weeks, the haemodynamic data and cardiac function were measured by a physiological recorder. The histological structure of the heart was evaluated by HE and picro-sirius red staining. The plasma concentration of norepinephrine (NE), renin activity, angiotensin II (Ang II) concentration and cardiac Ang II level were determined by radioimmunoassay. RESULTS:Compared with AC group, RDN improved cardiac diastolic function ［left ventricular end-diastolic pressure: (8.03±1.66) mmHg vs(15.77±2.14) mmHg; -dp/dt: (7 793±587) mmHg/s vs(6 353±475) mmHg/s; both P<0.01］, inhibited cardiac hypertrophy ［left ventricular index: 3.340±0.121 vs4.244±0.102; cardiomyocyte area: (332.9±28.9) μm2 vs(401.6±33.2) μm2; both P<0.01］ and attenuated cardiac fibrosis (collagen volume fraction: 7.76%±0.85% vs12.48%±1.82%; P<0.01) in aortic constricted rats. However, RDN didn’t cause significant reduction of blood pressure in aortic constricted rats (P>0.05). RDN prevented the AC-induced increase in the plasma NE concentration, renin activity, Ang II concentration and cardiac Ang II level. CONCLUSION: RDN may directly prevent cardiac hypertrophy and fibrosis and improve cardiac function via regulating the sympathomimetic activity and renin-angiotensin system.     

Effects of beta2-adrenergic blocker on cytosolic Ca2+ in isolated cardiomyocytes of rats with myocardial infarction

AIM: To investigate if beta2-adrenergic receptors result in more Ca2+ load after myocardial infarction (MI), the effects of beta2-adrenergic blocker on cytosolic Ca2+ (［Ca2+］i) were studied. METHODS: Male Wistar rats underwent a ligation of left coronary artery (n=9) or a sham operation (n=3). Cardiomyocytes were dissociated at 2, 4 and 8 weeks after MI and ［Ca2+］i was measured via fura-2 fluorescence. The response of cardiomyocytes to isoproterenol (1 μmol/L) in the presence or absence of atenolol (1 μmol/L), beta2-adrenergic blocker ICI118,551 (0.1 μmol/L) or propranolol (1 μmol/L) was examined. RESULTS: ICI118,551 suppressed the increase in ［Ca2+］i induced by isoproterenol at 4 and 8 weeks after MI (24.5%±5.7% vs 57.8%±13.2%, P<0.01; 12.2%±7.9% vs 44.6%±11.3%, P<0.01), but had no effects in control and 2 weeks post-MI groups. It decreased ［Ca2+］i in control and the three post-MI groups by 14.3%, 7.9%, 57.6% and 72.6%, respectively. Atenolol had suppressive effects only in control and 2 weeks post-MI groups (P<0.05). Propranolol had suppressive effects in control and all three post-MI groups (P<0.01). CONCLUSION: Beta 2-adrenergic blocker ICI118,551 exerts negative effects on ［Ca2+］i after MI, and the effects dramatically increase with the progression of MI.     

Effects of salinomycin combined with L-asparaginase on proliferation and apoptosis of human acute T-cell leukemia Jurkat cells

AIM:To investigate the effects of salinomycin alone or in combination with L-asparaginase on the growth and apoptosis of human acute T-cell leukemia Jurkat cells, and the possible mechanism. METHODS:The growth of Jurkat cells was tested by Cell Counting Kit-8 in vitro. The levels of cytochrome C, Bcl-2, caspase-3, caspase-8 and caspase-9 were measured by Western blotting. Flow cytometry was used to assay cell apoptosis. RESULTS:Salinomycin or L-asparaginase alone inhibited the growth of Jurkat cells in a dose-dependent manner. The IC50 value of L-asparaginase was 8.12 IU/L, while that of salinomycin was 0.75 μmol/L. Salinomycin combined with L-asparaginase induced more significant inhibition of cell proliferation (P<0.05). Western blotting showed that the expression of Bcl-2 protein in combination group was significantly reduced, and the expression of caspase-3, caspase-8, caspase-9 and cytochrome C was significantly increased (P<0.05). Flow cytometry showed that the apoptotic rates of Jurkat cells incubated with salinomycin (0.5 μmol/L), L-asparaginase (2.5 IU/L) and both drugs for 48 h were (7.11±0.23)%, (25.43±0.47)% and (39.12±1.97)%, respectively, and significantly higher than that in control group ［(6.67±0.13)%, P<0.05］.CONCLUSION: Salinomycin synergizes with L-asparaginase-induced cytotoxicity in vitro, and the combined treatment with salinomycin and L-asparaginase induces the apoptosis of Jurkat cells.     

Effect of rosiglitazone on myocardial energy substrate utilization in type 2 diabetic rats

AIM: To study the effect of rosiglitazone (RSG) to improve insulin sensitivity on myocardial energy substrate utilization as well as the cardiac function in a rat model of type 2 diabetes mellitus. METHODS: Sprague-Dawley rats were conducted into three groups: chow-fed rats were fed with normal chow (12% of calories as fat); fat-fed/STZ rats were fed with high-fat diet (40% of calories as fat) for 4 weeks and then injected with streptozotocin 35 mg/kg intraperitoneal; fat-fed/STZ/RSG rats were fat-fed/STZ rats treated with rosiglitazone (3 mg·kg-1·d-1) for 2 weeks. A cannula connected to a passive transducer was inserted the heart for the measurement of the cardiac function including heart rate (HR), left ventricular end-diastolic pressure (EDP) and ±dp/dtmax. Then the isolated hearts were mounted onto a Langendorff perfusion apparatus to perfuse with Krebs-Henseleit buffer in the presence of 5 mmol/L glucose and 0.4 mmol/L ［3H］ labelled palmitate. Glucose uptake and ［3H2O］ collection were measured to evaluate the rate of carbohydrate and fatty acid oxidation. RESULTS: Compared with the chow-fed rats, fat-fed/STZ rats had a significantly depression of glucose uptake in the hearts ［(54.7±6.2 vs 69.0±5.7) μmol·g-1 dry weight, P<0.01］ after 30 min perfusion. The oxidation of glucose and palmitate were 18% and 82%, respectively. Paralleling the reduction was a change of EDP ［(14.3±1.8 vs 10.5±1.1) mmHg, P<0.05］ and -dp/dt ［(550±57 vs 650±42) mmHg/s, P<0.01］, indicating a impaired left ventricular diastolic function. In the hearts subjected to fat-fed/STZ group, rosiglitazone treated for 2 weeks resulted in a elevated level of glucose uptake ［(63.5±6.4 vs 54.7±6.2) μmol·g-1 dry weight, P<0.05］. A protective role of the ventricular function ［EDP decreased from （14.8±1.9） to （11.0±0.8） mmHg/s and -dp/dtmax increased from （558±60） to （629±51） mmHg/s, P<0.05］ were observed. CONCLUSIONS: Our study indicates that there is a depression of glucose oxidation and at increase in fatty acid oxidation in type 2 diabetic hearts. Elevation of insulin sensitivity using rosiglitazone increases the myocardial glucose metabolism and shows a benefitial result to heart functions.     

Effects of adrenomedullin 2 on proliferation of microvascular endothelial cells from the rat cerebral cortex

AIM: To investigate the effects of adrenomedullin (ADM) 2 (AM2) on proliferation of microvascular endothelial cells from the rat cerebral cortex. METHODS: Microvascular endothelial cells (MEC) were isolated from the cerebral cortex of SD rats and cultured. The cultured cells were identified using immunocytochemistry assay with antibody for factor VIII-related antigen and randomly distributed into eight experimental groups as follows: control, AM2 10-7 mol/L, 10-8 mol/L, 10-9 mol/L, ADM, ADM+AM2, 10% fetal bovine serum (FBS) stimulated, and 10% FBS＋AM2 10^-7 mol/L groups. The proliferation of MEC was detected using ［3H］-TdR incorporation assay. RESULTS: Compared with control, AM2 (10^-7-10^-9 mol/L), ADM (10^-7 mol/L), and AM2 (10^-7mol/L) co-incubated with ADM (10^-7 mol/L) had no effects on ［3H］-TdR incorporation into the MEC (P>0.05). 10% FBS induced ［3H］-TdR incorporation increased by 87.5% (vs control, P<0.05), which was abolished by co-incubated the MEC with 10^-7 mol/L AM2 (P<0.05). CONCLUSION: AM2 inhibits FBS-stimulated proliferation of MEC from the rat cerebral cortex.     

早熟大粒无核葡萄新品种‘超级无核’

 ‘超级无核’葡萄系从美国引进葡萄新品种‘Superior Seedless’优选单株培育出的优良品种。无核、大粒、早熟、优质、早实、丰产、生长势强健、耐病、耐不利栽培条件, 是适合高温、高湿、少日照地区栽培的无核葡萄新品种。     

Effects of stretch on transient outward potassium and inward rectifier potassium current in cultured neonatal rat atrial myocytes

AIM：To investigate the effects of mechanical stretch on transient outward potassium current (Ito), inward rectifier potassium current (IK1) and action potential duration(APD) of cultured neonatal rat atrial myocytes. METHODS：Neonatal rat atrial myocytes were isolated and cultured on silicone sheeting with or without stretch for 24 h. The silicone membrane area was increased by 12% in stretched group. The cells without stretch served as control. Ito, IK1 and APD were recorded by the technique of whole-cell patch clamp. RESULTS：Compared with control group, Ito density in stretched myocytes was significantly reduced ［(16±04) pA/pF vs (121±29) pA/pF, P<001］, whereas IK1 density was increased ［(-108±08) pA/pF vs (-88±09) pA/pF, P<001］. The APDs at 50% and 90% levels of repolarization (APD50 and APD90) in the stretched cells were obviously decreased than those in non-stretched cells ［(105±14) ms vs (155±24) ms, (300±28) ms vs (563±36) ms, P<001］. CONCLUSION：Stretch stimulation leads to the reduction of Ito density, the increase in IK1 density and the shortness of APD in cultured rat atrial neonatal myocytes, which may contribute to atrial electrical remodeling induced by pressure overload.     

Genistein downregulates survivin gene expression and induces apoptosis in hepatocellular carcinoma HepG2 cells

AIM: To probe into the role of 1, 4, 5-trisphosphate inositol (IP3) and survivin protein in apoptosis of HepG2 cells induced by genistein. METHODS: HepG2 cells were treated with 60 μmol/L genistein for 12 h, 24 h, 48 h and 72 h. IP3, survivin and apoptosis rate were assayed by IP3-［3H］ Birtrak assay, Western blotting and flow cytometry, respectively. RESULTS: IP3 in groups incubated for 12 h, 24 h, 48 h and 72 h with 60 μmol/L genistein were significantly lower than that in control (P<0.01) ［(12.0±1.4) pmol/106cells, (7.5±0.8) pmol/106 cells, (5.6±0.5) pmol/106cells, (3.3±0.6) pmol/106 cells， vs (29.2±0.6) pmol/106 cells］. V-survivin/ V-β-actin, which was the gray degree multiply area of survivin/the gray degree multiply area of β-actin in groups incubated for 12 h, 24 h, 48 h and 72 h with 60 μmol/L genistein, were significantly lower than that in control (P<0.01) ［（0.36±0.13, 0.33±0.03, 0.23±0.04, 0.18±0.04）， vs 0.63±0.06］. The apoptosis rate in groups incubated with 60 μmol/L genistein for 24 h, 48 h and 72 h was significantly higher than that in control （P<0.01） ［(7.4%±0.5%, 20.5%±2.0%, 30.7%±1.6%) vs 2.6%±0.1%］. CONCLUSION: Genistein induces apoptosis in HepG2 cells by reducing IP3 production and survivin protein expression.     

Effects of pentoxifylline on ventricular remodeling and cardiac function of dilated cardiomyopathy rats

AIM: To explore the effects of pentoxifylline (PTX) on ventricular remodeling and cardiac function in dilated cardiomyopathy (DCM) rats.METHODS: Lewis rats were randomly allocated to a myocin-induced dilated cardiomyopathy (DCM) group receiving saline (n=10), a DCM group receiving PTX (PTX group; 25 mg·kg^-1·d^-1, ip, for 30 days, n=10) or healthy control group (n=10). The levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and IL-10 in the blood plasma were analyzed by ELISA. The extent of fibrosis was estimated using Massons staining and immunohistochemistry analyses. Cardiac structure and function were measured by echocardiography.RESULTS: PTX decreased plasma levels of TNF-α and IL-6, and increased IL-10 level in DCM animals compared with DCM group ［TNF-α: (7.21±0.24) μg/L vs (19.30±1.31) μg/L, P<0.01; IL-6: (119.60±36.58) ng/L vs (189.50±13.25) ng/L, P<0.05; IL-10: (41.26±3.27) μg/L vs (32.45±4.32) μg/L, P<0.05］. Collagen volume fraction (CVF), perivascular collagen area (PVCA) and collagen Ⅰ/Ⅲ ratio were lower in PTX group than those in DCM group ［CVF: (16.45±3.01)% vs (23.33±4.43)%, P<0.05; PVCA: 4.58±2.10 vs 13.74±4.29, P<0.05; Ⅰ/Ⅲ ratio: 2.84±0.67 vs 4.22±0.54, P<0.01］. Left ventricular end-diastolic dimension reduced ［(6.11±0.51) mm vs (6.46±0.28) mm, P<0.05］ and left ventricular ejection fraction elevated ［(77.29±5.20)% vs (62.73±10.11)%, P<0.01］ by PTX compared with DCM.CONCLUSION: PTX modulates plasma levels of inflammatory cytokines, delays the ventricle remodeling and improves the heart function in DCM rats.     

Effects of human urotensin II on ischemia/reperfusion injury in isolated perfused rat hearts

AIM: To investigate the effects of human urotensin II (hUII) on ischemia/reperfusion (I/R) injury in isolated rat hearts. METHODS: In the ischemia/reperfusion (I/R) model of isolated perfused rat hearts, the effects of hUII pretreatment on cardiac function was monitored with cardiac function software of MFL Lab200. ATP, total calcium, and malondialdehyde (MDA) content in myocardium were detected. The coronary perfusion flow (CPF) and lactate dehydrogenase (LDH) activity in coronary effluent were measured during reperfusion. RESULTS: In the hUII pretreated group, the release of LDH from myocardium was lower [(78.3±18.1)U/L] than I/R group [(109.3±23.9) U/L, P< 0.05], with decreased contents of MDA and calcium in myocardium (decreased by 24% and 27%, respectively, P< 0.05) and an increased myocardial ATP content [(3.8±0.4)μmol/g dw vs (2.2±0.4)μmol/g dw, P< 0.05)]. At the same time, hUII pretreatment increased CPF [(5.4±0.7) mL/min vs (3.8±0.8) mL/min in I/R group, P< 0.05], reduced left ventricular end-diastolic pressure (LVEDP) by 20% ( P< 0.05) with increased±d p /d t max [(217±38) kPa/s and (119±18) kPa/s vs (173±29) kPa/s and (82±25) kPa/s in I/R groups, respectively, P< 0.05]. hUII pretreatment also increased natrite/natrate (NO₂^-/NO₃^-) content in coronary effluent [(52.2±12.0)μmol/L vs (32.1±10.2)μmol/L in I/R group, P< 0.05)]. CONCLUSION: hUII pretreatment attenuated I/R injury in isolated perfused rat hearts. The protective mechanism might be associated with NO-mediated coronary vasodilation.     

Insulin-like growth factor I protects neonatal rat cardiomyocytes from apoptosis through improvement of mitochondrial function

AIM：To investigate whether mitochondrial mechanism is involved in the anti-apoptotic effect of insulin-like growth factor I (IGF-I) on cardiomyocytes. METHODS：Primary neonatal rat cardiomyocytes (NRCMs) were cultured and treated with 200 μmol/L hydrogen peroxide (H2O2) to induce apoptosis. Kruppel-like factor 9 (KLF9)-specific siRNA was transfected into the cells by Lipofectamine 2000. The mitochondrial function was measured by JC-1 mitochondrial membrane potential (MMP) assay. The mitochondrial morphology was observed by transmission electron microscopy. Myocardial cell apoptosis was detected by Annexin V-FITC/PI dual staining, caspase-3 activity assay, DNA-ladder analysis and Hoechst 33258 staining. RESULTS：The apoptosis of NRCMs was induced by H2O2, with MMP decreased by (24.0±1.6)% compared with control group. The fall rates of MMP in IGF-I group and KLF9 siRNA group were (18.3±1.2)% and (15.2±1.2)%, respectively (both P<0.01 vs H2O2 group), and improved mitochondrial morphology, decreased caspase-3 activity, attenuated DNA fragmentation and reduced apoptotic bodies were also observed in these two groups. The apoptotic rates of NRCMs in IGF-I group and KLF9 siRNA group were (22.4±4.2)% and (32.5±3.5)%, respectively, both lower than that in H2O2 group ［(42.5±1.8)%, P<0.01］. The anti-apoptotic effect of KLF9 silencing on NRCMs was consistent with that of IGF-I treatment. CONCLUSION：IGF-I protects NRCMs from apoptosis through down-regulating KLF9 expression and improving mitochondrial function.     

miR-155-specific siRNA enhances chemosensitivity of Burkitt lymphoma Raji cells to cytosine arabinoside by inducing apoptosis

AIM：To investigate the effect of miR-155-specific siRNA alone or in combination with cytosine arabinoside (Ara-C) on the growth and apoptosis of Burkitt lymphoma Raji cells. METHODS：miR-155-specific siRNA and/or Ara-C were used to treat the cells. Quantitative real-time polymerase chain reaction was used to detect the expression of miR-155. The growth of the cells was analyzed by CKK-8 assay. The cell apoptosis was determined by flow cytometry. RESULTS：The miR-155 expression level of the cells transfected with miR-155 siRNA was significantly lower than that in the 2 control groups. Ara-C or miR-155 siRNA alone inhibited the growth of Raji cells in a dose-depend manner. miR-155 siRNA combined with Ara-C produced more inhibition of cell proliferation (P<0.05). After treatment for 48 h, the apoptotic rate of Raji cells in miR-155 siRNA+Ara-C group ［(38.4±1.4)%］ was higher than that in Ara-C group ［(16.5±0.3)%］ and miR-155 siRNA group ［(14.6±0.3)%］, with statistically significant difference (P<0.05). The expression of caspase-3 in Ara-C+miR-155 siRNA group was increased significantly as compared with Ara-C group and miR-155 siRNA group. CONCLUSION：miR-155-specific siRNA enhances the chemosensitivity of Raji cells to Ara-C by inducing apoptosis through the caspase-3 pathway.