Effects of salvianolic acid B on the energy metabolism and hydrocephalus in mice with cerebral ischemia

AIM: To explore the effects of salvianolic acid B (SalB) on the energy metabolism and hydrocephalus in mice with cerebral ischemia.METHODS: NIH mice were randomly divided into four groups: sham-operated group,cerebral ischemia group,SalB-treated group and nimodipine-treated group.The brain tissue energy charge (EC),phosphocreatine (PCr),the activity of ATPase,excitability amino acid (EAA) content and water content of brain were measured when cerebral ischemia for 30 min.RESULTS: EC (0.520±0.034),PCr content ［(98.344±13.249) μmol/g］,the activity of Na⁺-K⁺-ATPase ［(0.593±0.013)×10³ U/g］ and Ca²⁺-ATPase ［(0.484±0.053)×10³ U/g］ in SalB-treated group were significantly higher than those in cerebral ischemia group {EC (0.465±0.037),PCr content ［(81.614±9.919) μmol/g］ ,the activity of Na⁺-K⁺-ATPase ［(0.244±0.065)×10³ U/g］,the activity of Ca²⁺-ATPase ［(0.321±0.086)×10³ U/g］} (P<0.01).The glutamate (Glu) content ［(0.405±0.110) μmol/g］,aspartate (Asp) content ［(0.141±0.020) μmol/g］ and water content of brain ［(38.1±0.1)%］ in SalB-treated group were markedly lower than those in cerebral ischemia group ［ Glu content (0.550±0.140) μmol/g,Asp content (0.287±0.050) μmol/g,water content of brain (44.1±0.1)%］ (P<0.05,P<0.01).CONCLUSION: The increase in cerebral energy metabolism and the activity of ATPase,and decrease in EAA content in brain tissue are the mechanism of SalB alleviating hydrocephalus at the early stage of cerebral ischemia in mice.     

Synergistic effect of decitabine and valproic acid on apoptosis and cell cycle arrest at G0/G1 phase in gastric cancer MGC-803 cells

AIM: To investigate the synergistic effect of decitabine (DCA) and valproic acid (VPA) on apoptosis and cell cycle arrest at G₀/G₁ phase in gastric cancer MGC-803 cells. METHODS: Gastric cancer MGC-803 cells were used in the study and divided into the following groups according to the treatment with different drugs for 72 h: DCA 1.5 μmol/L,DCA 3.0 μmol/L, VPA 1.5 mmol/L, DCA 1.5 μmol/L+VPA 1.5 mmol/L and DCA 3.0 μmol/L+VPA 1.5 mmol/L. The early and late apoptotic rates were detected by annexin V and PI staining. The cell cycle was also determined by flow cytometry. The relative nm23-H1 mRNA expression level was measured by real-time quantitative PCR. RESULTS: The apoptotic rates in VPA 1.5 mmol/L+DCA 1.5 μmol/L group (early: 33.58%±3.88%; late: 31.52%±4.20%) and VPA 1.5 mmol/L+DCA 3.0 μmol/L group (early: 42.61%±4.23%; late: 38.01%±3.86%), the percentages of the cells in G₀/G₁ phase in VPA 1.5 mmol/L+DCA 1.5 μmol/L group (61.55%±2.38%) and VPA 1.5 mmol/L+DCA 3.0 μmol/L group (66.75%±2.48%), and the relative nm23-H1 mRNA expression levels in VPA 1.5 mmol/L +DCA 1.5 μmol/L group (1.84±0.46) and VPA 1.5 mmol/L+DCA 3.0 μmol/L group (3.02±0.36) were all significantly higher than those in the corresponding concentrations of single drug treatment groups (P<0.01). CONCLUSION: Synergistic effect of VPA and DCA on apoptosis and cell cycle arrest in gastric cancer MGC-803 cells is possibly via inactivation of nm23-H1 gene expression.     

Correlation of serum uric acid level with carotid plaques and arterial stiffness in patients with essential hypertension

AIM：To study the correlation of serum uric acid (UA) level with carotid plaques and arterial stiffness in the patients with essential hypertension (EH), and to explore the predictive value of serum UA for evaluating EH preclinically. METHODS：A total of 92 patients with EH and 30 healthy individuals were enrolled. The value of UA and other indicators were detected. B-mode ultrasound examination was performed to measure the common carotid artery intima-media thickness (IMT) and the sites of plaque in the internal carotid-artery, external carotid artery and carotid bifurcations. Carotid-femoral arterial pulse wave velocity (CFPWV) was assessed by Complior atherosclerosis measurement instrument. RESULTS：The serum level of UA in the patients with EH was higher than that in control group ［(361.51±83.81） μmol/L vs (317.03±62.22) μmol/L, P<0.05］. The mean value and abnormal rate of IMT between hypertension group and control group were significant difference ［(0.69±0.14) mm vs (0.60±0.12) mm, 42.39% vs 10.00%, P<0.05］. In 92 EH patients, 45 cases had carotid plaques. These 45 cases were divided into 3 groups according to the plaque severity, among which the serum UA level had statistically significant differences ［(285.25±78.41） μmol/L, （341.19±63.99） μmol/L and （401.33±88.49） μmol/L, P< 0.05］. Compared with rigid plaque group (n=34), the serum UA level in soft plaque group (n=11) was significantly higher ［(389.00±69.45) μmol/L vs （323.03±72.71） μmol/L, P<0.05］. A stepwise multiple linear regression analysis demonstrated that age (r=0.414), systolic blood pressure (r=0.224), pulse pressure (r=0.270) and uric acid (r=0.219) were predisposed factors for higher CFPWV (P<0.05). CONCLUSION：UA is one of the risk factors causing hypertension. Serum UA level may reflect the severity and stability of carotid plaques. The increased arterial stiffness is closely related to the increased serum UA level in EH.     

Hepatocyte protection of ethyl pyruvate in septic mice

AIM:To study the protective effect of ethyl pyruvate (EP) on hepatocytes in septic mice. METHODS:The cecal ligation-perforation was made in mice as septic model. Ringers ethyl pyruvate solution (REPS) and Ringers lactic solution (RLS) were used to resuscitate septic mice. Anti-oxidative capacity of hepatic tissue and liver function were detected in different groups. RESULTS:Anti-oxidative capacity in septic mice was significantly lower than that in sham group (P<0.01). EP promoted the anti-oxidative capacity of hepatic tissue in septic mice. Malondialdehyde level was lower in REPS group than that in RLS group ［(48.18±5.98) μmol·g-1 protein vs (78.34±11.16) μmol·g-1 protein］, superoxide dismutase ［(5.19±1.41)103 U/g protein vs (3.20±1.08)103 U/g protein］ and total anti-oxidative capacity ［(7.02±1.79)103 U/g protein vs (4.77±1.35)103 U/g protein］ level were higher in REPS group than those in RLS group (P<0.01). Alanine aminotransferase in REPS group were lower than that in RLS group ［(210.06±23.36) U vs (458.86±51.55) U, P<0.01］. CONCLUSION:Ethyl pyruvate is an effective anti-oxidant in septic mice, which significantly increases the anti-oxidative capacity in hepatic tissue and ameliorates liver function.     

Effect of preconditioning with pioglitazone on ischemia reperfusion/hypoxia reoxygenation-induced mitochondrial structure and membrane potential in rats

AIM: To observe the effect of preconditioning with pioglitazone on ischemia reperfusion/hypoxia reoxygenation-induced mitochondrial ultramicro-structure and membrane potential in rats. METHODS: Sprague-Dawley rats were randomly divided into four groups: sham-operated (SO) group, ischemia reperfusion (IR) group, pioglitazone preconditioning group (Pio-P) and 5-HD+pioglitazone (5-HD+Pio) group. Apart from the SO group, IR, Pio-P and 5-HD+Pio groups were subjected to 30 min ischemia and 4 h reperfusion. The heart was quickly removed for observing the structure of mitochondria and measurement of the apoptosis index (AI) by TUNEL. Primary cultured cardiomyocytes of Sprague-Dawley rats were divided into control, hypoxic reoxygenation (HR) and different concentrations of Pio-P group. JC-1 staining flowcytometry was adopted to examine mitochondrial membrane potential (ΔΨm). RESULTS: The injury of mitochondrial structure in IR group was severer than that in Pio-P group, while the difference between 5-HD+Pio group and IR group was not evident. Flameng score in Pio-P group(1.62±0.60) was significantly lower than that in IR group (2.75±1.09), P<0.01. AI in Pio-P group (28.19%±4.93%) was lower than that in IR group (55.44%±6.63%),P<0.05. The rates of low ΔΨm cells in (5 μmol/L,10 μmol/L and 15 μmol/L) Pio-P group were (45.89±3.63)%, (17.13±1.37)% and (18.43±2.44)%, significantly lower than that in HR group (56.52%±2.87%),P<0.05, while the difference between 10 μmol/L group and 15 μmol/L group was not significant (P>0.05). CONCLUSION: Pioglitazone protects the heart from ischemia reperfusion/ hypoxia reoxygenation injury evidenced by improving mitochondrial ultrastructure and lessening the loss of mitochondrial membrane potential, and decreasing apoptosis. The cardioprotective effects can be inhibited by the blocker of mitochondrial ATP-sensitive potassium channels.     

Significance of soluble CD40 ligand in the vulnerability of coronary atherosclerotic plaque

AIM: To evaluate the significance of serum soluble CD40 ligand (sCD40L) in the vulnerability of coronary atherosclerotic plaque, the relationship between the level of sCD40L and the stenosis degree of the coronary artery by the coronary angiography (CAG), and other inflammatory factors. METHODS: According to WHO diagnostic criterior of coronary heart disease (CHD) and the results of CAG, 84 cases of CHD and 20 cases of non-CHD (NCHD) were included in this study. 84 cases of CHD were divided into three groups: 30 cases in acute myocardial infarction (AMI) group, 30 cases in unstable angina (UA), 24 cases in stable angina (SA). The sera levels of sCD40L in four groups were detected by the enzyme-linked immunosorbent assay (ELISA) and the results were expressed with μg/L. CAG were all conducted in four cases and the results were further evaluated by Jenkins score. ESR and CRP were detected at the same time. RESULTS: The sera levels of sCD40L in four groups were significantly different (P<0.01). The level of sCD40L in AMI group (8.48±4.13) μg/L was higher than that in SA group (4.36±2.68) μg/L, P<0.01 and NCHD group (4.12±1.96) μg/L, P<0.01. The level of sCD40L in UA group (8.72±4.26) μg/L was higher than that in SA group and NCHD group (P<0.01). The level of sCD40L in UA group was slightly higher than that in AMI group, but the difference of two group is not significant (P>0.05). The level of sCD40L in SA group was slightly higher than that in NCHD group, but the difference of two group is not significant (P>0.05). The sera levels of sCD40L in CHD were significantly and positively correlated with Jenkins score (r=0.524, P<0.01). The sera level of sCD40L was positively correlated with the levels of CRP and ESR. CONCLUSION: The sera levels of sCD40L in the patients with various types of CHD are significantly different. The level of sCD40L in the patients with AMI and UA are significantly higher than those in SA and NCHD groups, which may reflect the vulnerability of coronary atherosclerotic plaque. The sera levels of sCD40L is increased with the increasing number of diseased coronary branches and Jenkins score, suggesting that sCD40L promotes atherosclerosis and also can be used as a parameter to predict pathological severity of coronary atherosclerosis. The level of sCD40L is obviously correlated with the levels of CRP and ESR.     

Characteristics and pathomechanisms of hyperuricemia combined with hypertriglyceridemia and hyperglycemia in a coturnix model induced by high-purine diet

AIM: To investigate the pathomechanisms in a coturnix model of high-purine diet and the metabolic characteristics of glucose and lipids. METHODS: Twenty-four French male quails were randomly divided into 2 groups: control group and model group. The animals in control group were fed with normal diet and the quails in model group were fed with high-purine diet. The body weight, serum uric acid (UA), triglyceride (TG), glucose (GLU), the activity of xanthine oxidase (XOD), guanine deaminase (GuDa) and glyceraldehyde phosphate dehydrogenase (GAPDH), and the level of insulin (Ins) were determined. RESULTS: No change of body weight in model group was observed. In model group, the serum levels of UA,TG and GLU were significantly increased from 10 d to 140 d, 60 d to 140 d and 90 d to 140 d, respectively. At 10 d, 60 d and 140 d, the activity of XOD in model group was significantly higher than that in control group. From 30 d to 140 d, the activity of GAPDH was significantly decreased. From 60 d to 140 d, the level of Ins was significantly increased. CONCLUSION: (1) High-purine diet induces multiple metabolic disorders of UA, TG and GLU. (2) The pathologic processes can be divided into three stages: simple hyperuricemia in the first stage, hyperuricemia combined with hypertriglyceridemia in the second stage and hyperuricemia combined with hypertriglyceridemia and hyperglycemia in the third stage. (3) The pathomechanisms may relate to the increased activity of XOD, decreased activity of GAPDH and increased level of Ins.     

Modulation of interleukin-2 on the positive effect of isoproterenol in the isolated cardiomyocytes

AIM: To explore the effects and mechanism of interleukin-2 (IL-2) on the positive effect of isoproterenol (ISO) in the isolated rat cardiomyocytes. METHODS: Enzymatically isolated cardiomyocytes were used. Peak twitch amplitude and maximal velocity of shortening/relaxation (±dL/dtmax) in the isolated cardiomyocytes were recorded with a microscope coupled to a charge-coupled device camera and ［Ca2+］i transients were determined with a fluorometric ratio method by using Fura-2/AM as Ca2+ indicators. RESULTS: ① ISO increased the peak twitch amplitude and ±dL/dtmax of the isolated cardiomyocytes. Perfusion for 15 min with IL-2 at 2×103 U/L, which had no effect at all, attenuated the enhancing effect of ISO on the peak twitch amplitude and ±dL/dtmax. ② ISO increased the ［Ca2+］i transients of the single ventricular myocytes in a dose dependent manner and the corresponding EC50 values of ISO was (0.12±0.01) μmol/L. Perfusion for 15 min with IL-2 at 2×103 U/L, which had no effect on the ［Ca2+］i transient at all, attenuated the enhancing effect of ISO and the corresponding EC50 was (0.44±0.06) μmol/L. ③ The electrically induced ［Ca2+］i transient was significantly increased by pretreatment with 20 mg/L cholera toxin for 12 h. The elevation of the ［Ca2+］i transient induced by cholera toxin was significantly attenuated by 2×103 U/L IL-2. ④ Forskolin (1 μmol/L), the activator of adenyl cyclase, significantly increased the electrically induced ［Ca2+］i transient, which was attenuated by IL-2 at 2×103 U/L. CONCLUSION: IL-2 inhibits the positive effect of isoproterenol in the isolated single ventricular myocytes, in which Gs protein and adenyl cyclase are involved.     

Effect of electro-acupuncture at Zusanli point on tumor necrosis factor-α induced-multiple organ dysfunction in rats with sepsis

AIM: To investigate the effect of electro-acupuncture (EA) at Zusanli (ST36) on proinflammatory factors induced-multiple organ dysfunction in rats with sepsis. METHODS: Sixty four male Wastar rats were used to develop the sepsis model by cecal ligation and puncture (CLP). The animals were randomly divided into 4 groups (n=16 in each group): CLP+EA (CLP/EA), CLP+sham EA (CLP/SEA), vagotomy+ CLP+SEA (VA/CLP/SEA) and vagotomy+CLP+EA (VA/CLP/EA). Zusanli point (ST36) was electroacupunctured with constant voltage (2-100 Hz, 2 mA for 0.5 h) 20 min after CLP surgery. Bilateral cervical vagotomies were performed in rats in VA/CL/SEA and VA/CLP/EA groups. Twelve hours after CLP, animals were sacrificed and liver, kidney and jejunum were harvested for evaluating the contents of tumor necrosis factor-α (TNF-α), myeloperoxidase (MPO) and diamine oxidase (DAO). The rate of water content (WCR) of the organs was determined. At the same time, the plasma levels of alanine aminotransferase (ALT) and creatinine (Cr) in each group were also detected. RESULTS: The levels of ALT and Cr in plasma, as well as TNF-α, MPO and WCR in organ tissues were markedly lower, and the activity of DAO in jejunum tissue was obviously higher than that in CLP/SEA group at 12 h after CLP (all P<0.05). The levels of ALT, Cr, TNF-α, MPO and WCR in VA/CLP/SEA group and VA/CLP/EA group were significantly higher, the activity of DAO was obviously lower than that in CLP/SEA group (all P<0.05). No statistical difference in all above measurements between VA/CLP/EA group and VA/CLP/SEA group was observed (all P>0.05). CONCLUSION: The results indicate that EA at Zusanli point obviously decreases the levels of TNF-α in liver, kidney and jejunum tissues after CLP, and alleviates the tissue edema and dysfunction of those organs. Vagotomy decreases or eliminates the effects of EA, suggesting that activation of cholinergic anti-inflammatory pathway is one of the main mechanisms to induce the effects of EA at ST36 on CLP sepsis.     

Effect of TMB-8 on the activation,proliferation and cell-cycle distribution of the mouse T lymphocytes in vitro

AIM: To study the effects of ［8-(diethylamino) octyl-3, 4, 5 -trimethoxybenzoate］ (TMB-8), an intracellular Ca2+ antagonist, on the activation, proliferation and cell-cycle distribution of the mouse T lymphocytes stimulated by concanvalin A (Con A) in vitro. METHODS: After stimulated with Con A, T cells were treated with different concentrations of TMB-8 alone and its combination with cyclosporine A (CsA). The expression of CD69, the early marker of CD3+ T cell activation, was measured by FACS. The proliferation-related index was determined by carboxyl fluorescin diacetate succinmidyl ester (CFDA-SE) flow cytometry. The cell-cycle distribution was analyzed by propidium iodide staining.RESULTS: After 6 h culture, the activation rate of CD69+ T cell in Con A group was (74.88±1.88)%. 10, 20 and 40 μmol/L of TMB-8 inhibited the expression of CD69 (P<0.01), especially in 40 μmol/L (52.55%±1.54%). After 48 h and 72 h culture, the PI of Con A group was 1.24±0.01, 2.05±0.07, respectively. TMB-8 with the concentration up to 5 μmol/L exerted a definite inhibitory effect on the proliferation with a maximal inhibition in 40 μmol/L(P<0.01). In the combination of 10 μmol/L of TMB-8 with 25 μg/L of CsA, an evident synergistic effect was observed (P<0.01). Moreover, the cell-cycle distribution analysis showed that after 48 h culture, the concentration of TMB-8 over 10 μmol/L showed an evident suppression in S phase.CONCLUSION: TMB-8 significantly inhibites the early steps of the Con A-induced T cell activation and proliferation, as well as the progression of T lymphocytes in S phase.     

Effect of shRNA-mediated survivin gene silencing on sensitivity of lymphoma cells to adriamycin

AIM: This study was designed to use RNA interference technique to down-regulate the expression of survivin gene in human Burkitts lymphoma cell line Daudi and to explore the effect on sensitivity of Daudi cells to adriamycin. METHODS: The survivin-shRNA expression vector was constructed and transfected into Daudi cells. Expression of survivin mRNA and protein were assessed by RT-PCR and Western blotting analysis, respectively. Apoptosis index of transfected Daudi cells was quantified by flow cytometry. The sensitivity of Daudi cells to adriamycin (ADR) before and after transfection was detected by MTT test. RESULTS: The mRNA and protein levels of survivin were down-regulated by 62.32% and 61.88%, respectively, compared to those in control-shRNA treated group and PBS treated group (P<0.05). Meanwhile, the apoptosis index was significantly increased (19.10%±2.15%), compared to that in control group (4.48%±1.54%) and PBS group (4.35%±1.37%, P<0.05). The 50% inhibition concentration (IC50) of ADM to Daudi cells was significantly decreased (0.25±0.43) μmol/L, compared to that in control group (0.87±0.21) μmol/L and PBS group (0.91±0.36) μmol/L, P<0.05. CONCLUSION: Down-regulation of survivin expression in Daudi cells by shRNA effectively induces apoptosis and increases the sensitivity of Daudi cells to ADR.     

Effect of insulin on early myocardial oxidative stress in severely burnt rats

AIM：To investigate the effect of insulin on early myocardial oxidative stress in severely burnt rats. METHODS：Twenty-four Sprague-Dawley rats were randomly divided into three groups (8 rats in each group): control group (sham scald group), scald injury group and scald injury + insulin group. The rats in the latter two groups were subject to third-degree burn with 30% total burn surface area (TBSA) on the back, and then received intraperitoneal injection of normal saline (40 mL/kg) immediately. The rats in scald injury + insulin group were subcutaneously injected with insulin (1 U/kg), while those in scald injury group received subcutaneous injection of the same volume of normal saline. All rats were sacrificed 24 h after scald, and blood samples from abdominal aorta and myocardial tissues were taken. Blood glucose (BG) content, blood lactate dehydrogenase (LDH) and creatine kinase (CK) activity, and myocardial oxidative and antioxidative indexes, including malondialdehyde (MDA), xanthine oxidase (XO), myeloperoxidase (MPO), superoxide dismutase (SOD), catalase (CAT) and glutathion peroxidase (GPx), were detected by spectrophotometry. RESULTS：(1) Compared with control group, BG levels in scald injury group and scald injury + insulin group were significantly elevated (P<0.05). But BG in scald injury + insulin group was significantly lower than that in scald injury group (P<0.05). (2) Compared with control group, the activity of LDH and CK in scald injury group was significantly increased (P<0.05), while that in scald injury + insulin group was significantly lower than that in scald injury group (P<0.05). (3) Compared with control group, the MDA content and the XOD and MPO activity in scald injury group were significantly increased (P<0.05), while the activity of SO, CAT and GPx was significantly decreased (P<0.05). Compared with scald injury group, the MDA content and the XO and MPO activity in scald injury + insulin group were significantly reduced (P<0.05), while the activity of SOD, CAT and GPx was significantly elevated (P<0.05). CONCLUSION：Insulin intervention attenuates early myocardial oxidative stress in burnt rats and decreases the rise in myocardial enzyme activity, thus exerting a cardioprotective effect.     

Changes of gut mucosa antioxidant system and liver,renal function in rats after intestinal ischemia-reperfusion injury

AIM: To investigate the changes of the gut mucosa antioxidant system and liver, renal functions during rat intestinal ischemia-reperfusion injury. METHODS: 30 male Wistar rats underwent 45 min of intestinal ischemia by clamping the superior mesenteric artery followed by reperfusion. The levels of malondialdehyde (MDA), glutathione (GSH), the activities of antioxidant enzymes in the gut mucosa including catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), glutathione S- transferase (GST) activity and serum ALT, AST, BUN, Cr were assayed at 2, 4, 8, 12 and 24 h after reperfusion. RESULTS: The levels of MDA and GSH in the gut mucosa increased and decreased significantly at 2 h of reperfusion, respectively (P<0.05). MDA was still lower than sham at 24 h of reperfusion (P<0.05), while GSH decreased to 40% of sham at 4 h of reperfusion (P<0.01) but returned to the level of control at 12 h. The activities of CAT, SOD and GSH-Px did not show significant changes in rat after intestinal ischemia reperfusion. GST decreased 39% at 2 h of reperfusion compared with the sham group and decreased to 56% of sham at 4 h (P<0.05), but returned to the level of control at 12 h after reperfusion. Serum ALT, AST, BUN and Cr increased significantly at 2 h of reperfusion (P<0.05) and increased 208%, 100%, 103%, 41% compared with control at 4 h of reperfusion (P<0.01). However, at 24 h of reperfusion, they returned to normal. CONCLUSION: Intestinal ischemia/reperfusion diminishes GSH level and GST activity, increases MDA level and causes liver and renal reversible damages.     

Effects of glucagon-like peptide-1 on myocardial ischemia-reperfusion/hypoxia-reoxygenation injury in rats

AIM: To investigate the effects of glucagon-like peptide-1 (GLP-1) on myocardial ischemia-reperfusion (IR)/hypoxia-reoxygenation (HR) injury in rats. METHODS: Sprague-Dawley rats were randomly divided into 5 groups: sham group, IR group and IR+GLP-1 (0.03 nmol/L, 0.16 nmol/L and 0.30 nmol/L) groups. IR group and IR+GLP-1 group were subject to 30 min of ischemia and 3 h of reperfusion. The myocardial infarct size, the ultrastructural changes of the myocardial tissues, the apoptosis of the cardiomyocytes, the activity of superoxide dismutase (SOD) and the concentration of malondialdehyde (MDA) were detected. Primarily cultured cardiomyocytes were divided into 5 groups at random: control group, HR group and HR+GLP-1 (1 μmol/L, 5 μmol/L and 10 μmol/L) groups. The morphology and apoptosis of the cardiomyocytes were observed. The levels of lactate dehydrogenase (LDH),MDA,SOD,reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) in different groups were detected. RESULTS: Compared with IR group, the myocardial infarct size and cardiomyocyte apoptosis were remarkably reduced, mitochondrial ultrastructures were improved, the activity of SOD was increased and the concentration of MDA was decreased in IR+GLP-1 (0.03 nmol/L, 0.16 nmol/L and 0.30 nmol/L) groups. Compared with HR group, GLP-1 (1 μmol/L, 5 μmol/L and 10 μmol/L) preconditioning significantly decreased the myocardial injury, increased SOD activity, decreased MDA concentration and ROS production, and heightened MMP in a dose-dependent manner. CONCLUSION: GLP-1 protects cardiomyocytes from IR/HR injury, which may be partially due to the effects of anti-oxidative mechanism and the function of mitochondrial protection.     

Relationship between polymorphism of angiotensin I converting enzyme gene insertion/deletion and ACE,PAI-1 activity in patients with myocardial infarction

AIM:To explore the relationship between polymorphism of angiotensin I converting enzyme gene insertion/deletion (I/D) and ACE, PAI-1 activity in patients with myocardial infarction (MI). METHODS:Ninety-three patients with MI and eighty-seven healthy controls were tested. ACE genomic DNA was amplified using the polymerase chain reaction (PCR). Serum ACE activity was measured by colorimetry, plasma level of PAI-1 activity was determined by spectrophotometric assay. RESULTS:① The frequency of ACE DD genotype and D alleles (32.3% and 54.3%) in MI group was significantly higher than those in control group (12.6% and 37.4%, P<0.01, respectively). ② The ACE activity in serum (216.00±58.26)U/L and plasma PAI-1 activity (0.85±0.19)AU/mL in MI group were significantly higher than those in control group (170.19±48.99)U/L, (0.66±0.20)AU/mL, P<0.01, respectively. The serum ACE activity was positively correlated with plasma PAI-1 activity both in MI group and control group (r=0.7108 and r=0.7829;P<0.01, respectively). ③ In MI group, the serum ACE activity and plasma PAI-1 activity showed a significantly higher level in subjects with DD genotype (251.64±57.76)U/L, (0.96±0.16)AU/mL than those with ID (211.47±51.87)U/L, (0.82±0.18) AU/mL and Ⅱ genotypes (179.84±52.65)U/L, (0.71±0.17)AU/mL. The serum ACE activity and plasma PAI-1 activity were significantly higher in subjects with ID genotype than those with II genotype (P<0.05). In control group, the serum ACE activity and plasma PAI-1 activity showed a significantly higher level in subjects with DD genotype (195.53±54.76)U/L, (0.78±0.20)AU/mL than the subjects with Ⅱ genotype (154.98±52.74)U/L, (0.59±0.17)AU/mL (P<0.05). CONCLUSION:The increased ACE activity caused by DD polymorphism may play an important role in elevating the level of plasma PAI-1. The DD genotype of ACE is associated with high PAI-1 level. The genetic variation of ACE contributes to the balance of fibrinolytic pathway, indicating the pathogenesis mechanisms linking to the ACE I/D genotype and MI.     

Effects of high hydrostatic pressure on ADMA metabolism in human vascular endothelial cells and the role of RAS

AIM:To observe the effects of high hydrostatic pressure on asymmetric NG, NG-dimethyl-L-arginine (ADMA) metabolism of human vascular endothelial cells (HUVECs), and the role of renin-angiotensin system (RAS). METHODS:Cultured HUVECs of 3-6th passage were exposed to atmosphere (0 mmHg, APC), 120 mmHg (MPC), 180 mmHg (HPC). There were three groups in each pressure condition, one as control, the other two were interfered with captopril （Cap, 10 μmol/L or 100 μmol/L） or irbesartan （Irb, 10 μmol/L or 100 μmol/L） respectively. Cell proliferation was quantified by determining hexosaminidase activity at 12 h. Concentration of ADMA in conditioned medium was measured by high performance liquid chromatography (HPLC) at 12 h. RESULTS:Compared with APC group, ADMA concentration increased prominently in MPC and HPC (4.69±0.37 and 4.48±0.39 vs 0.75±0.05，P<0.01), but no difference was found between MPC and HPC group. ADMA concentration was not influenced by Cap and Irb in APC, but obviously reduced in MPC and HPC in a dose-dependent manner. CONCLUSION:ADMA is upregulated by high hydrostatic pressure and RAS is involved.     

Protective effect of atrial natriuretic peptide on alveolar type II cells

AIM: To study the protective effect of atrial natriuretic peptide (ANP) on alveolar type II cells (AT-Ⅱ) damaged by lipopolysaccharide (LPS).METHODS: AT-Ⅱ were placed in a 6 well cell culture cluster (0.5×106 cells/cm2) and divided into 3 groups: (1) control group (n=6), the medium consisted of RPMI-1640 without FBS. (2) LPS group (n=6), the medium consisted of RPMI-1640 without FBS supplemented with LPS (1 mg/L). (3) ANP group (n=6), the medium consisted of RPMI-1640 without FBS supplemented with LPS (1 mg/L) and ANP (10-8, 10-7, 10-6 mol/L). After 4, 12 and 24 h, the cell culture mediums of control group, LPS group and ANP (10-7 mol/L) group were collected, and those of the ANP (10-6, 10-8 mol/L) group were collected after 12 h. Alkaline phosphatase(AKP), lactate dehydrogenase(LDH), malondialdehyde(MDA), total phospholipids (TPL) and surface tension (ST) in the medium of every group were examined. RESULTS: AT-Ⅱ were characterized by AKP staining. The contents of LDH, AKP and MDA in the medium of every ANP group were lower than those in the corresponding LPS group. The TPL content in the medium of every ANP group was higher than that in the corresponding LPS group, and the change of ST of the medium was opposite to that of TPL. The effect at 12 h was the most significant, for example, at 12 h, the activities of AKP in the mediums were: control (43.5±10.4) U/L, LPS (98.1±16.4) U/L, LPS+ANP (10-6) (46.4±10.5) U/L, LPS+ANP(10-7) (60.7±9.5) U/L, LPS+ANP(10-8) (91.3±13.9) U/L.CONCLUSION: ANP protects the AT-Ⅱ from being damaged by LPS and promotes the secretion of pulmonary surfactants.     

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 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.