Alleviation of plasma homocysteine level by phytoestrogen α-zearalanol might be related to the reduction of cystathionine ß-synthase nitration.

Hyperhomocysteinemia is strongly associated with cardiovascular diseases. Previous studies have shown that phytoestrogen α-zearalanol can protect cardiovascular system from hyperhomocysteinemia and ameliorate the level of plasma total homocysteine; however, the underlying mechanisms remain to be clarified. The aim of this research is to investigate the possible molecular mechanisms involved in ameliorating the level of plasma homocysteine by α-zearalanol. By the successfully established diet-induced hyperhomocysteinemia rat models, we found that, after α-zearalanol treatment, the activity of cystathionine ß-synthase, the key enzyme in homocysteine metabolism, was significantly elevated and level of nitrative stress in liver was significantly reduced. In correlation with this, results also showed a decreased nitration level of cystathionine ß-synthase in liver. Together data implied that alleviation of plasma homocysteine level by phytoestrogen α-zearalanol might be related to the reduction of cystathionine ß-synthase nitration.

Cardioprotective effects of adipokine apelin on myocardial infarction.

Angiogenesis plays an important role in myocardial infarction. Apelin and its natural receptor (angiotensin II receptor-like 1, AGTRL-1 or APLNR) induce sprouting of endothelial cells in an autocrine or paracrine manner. The aim of this study is to investigate whether apelin can improve the cardiac function after myocardial infarction by increasing angiogenesis in infarcted myocardium. Left ventricular end-diastolic pressure (LVEDP), left ventricular end systolic pressure (LVESP), left ventricular developed pressure (LVDP), maximal left ventricular pressure development (±LVdp/dtmax), infarct size, and angiogenesis were evaluated to analyze the cardioprotective effects of apelin on ischemic myocardium. Assays of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, 5-bromo-2'-deoxyuridine incorporation, wound healing, transwells, and tube formation were used to detect the effects of apelin on proliferation, migration, and chemotaxis of cardiac microvascular endothelial cells. Fluorescein isothiocyanate-labeled bovine serum albumin penetrating through monolayered cardiac microvascular endothelial cells was measured to evaluate the effects of apelin on permeability of microvascular endothelial cells. In vivo results showed that apelin increased ±LV dp/dtmax and LVESP values, decreased LVEDP values (all p < 0.05), and promoted angiogenesis in rat heart after ligation of the left anterior descending coronary artery. In vitro results showed that apelin dose-dependently enhanced proliferation, migration, chemotaxis, and tube formation, but not permeability of cardiac microvascular endothelial cells. Apelin also increased the expression of vascular endothelial growth factor receptors-2 (VEGFR2) and the endothelium-specific receptor tyrosine kinase (Tie-2) in cardiac microvascular endothelial cells. These results indicated that apelin played a protective role in myocardial infarction through promoting angiogenesis and decreasing permeability of microvascular endothelial cells via upregulating the expression of VEGFR2 and Tie-2 in cardiac microvascular endothelial cells.

Relationship between the autoantibody and expression of ß3-adrenoceptor in lung and heart.

BACKGROUND: Evidences suggest that ß3 -adrenoceptor (ß3-AR) plays an important role in heart failure (HF), although no data is reported indicating how these effects may change with the increasing age. Pulmonary congestion and edema are the major life-threatening complications associated with HF. The purpose of this study is to explore the relationship between the anti-ß3-AR autoantibody and the expression of ß3-AR in the lungs and heart for both aged patients and rats with HF. METHODS: Synthetic ß3-AR peptides served as the target antigens in ELISA were used to screen the anti-ß3-AR autoantibody in aged patients and rats. Two aged rat models were constructed based on aortic banding and sham-operation. The expression of ß3-AR mRNA and protein in the lung and heart was measured in intervention and non-intervention groups by Western blot analysis at the baseline, 5(th), 7(th), 9(th) and 11(th) week, respectively. RESULTS: The frequency and titer of anti-ß3-AR autoantibody in aged patients and rats with HF were higher than those in the control group (p<0.05). The expression of ß3-AR mRNA and protein in pulmonary tissues decreased continually from the 7(th) week (p<0.05), followed by HF observed during the 9(th) week. The expression of ß3-AR in myocardial tissues continued to increase after the 9(th) week (p<0.05), and the expression of both ß3-AR mRNA and protein in the BRL group [HF group with BRL37344 (4-[-[2-hydroxy-(3-chlorophenyl)ethyl-amino] phenoxyacetic acid) (a ß3-AR agonist) injection] was positively correlated with BRL37344 when compared with non-BRL group (HF group without BRL37344 injection) (p<0.05). CONCLUSION: Anti-ß3-AR autoantibody was detected in aged patients and rats with HF. The expression of ß3-AR mRNA and protein in pulmonary tissues decreased continually, and began earlier than in the heart, but its expression in myocardial tissues increased continually and could be further promoted by ß3-AR agonist.

Genistein attenuates vascular endothelial impairment in ovariectomized hyperhomocysteinemic rats.

Hyperhomocysteinemia (HHcy) is a well-known independent risk factor for vascular diseases in the general population. This study was to explore the effect of genistein (GST), a natural bioactive compound derived from legumes, on HHcy-induced vascular endothelial impairment in ovariectomized rats in vivo. Thirty-two adult female Wistar rats were assigned randomly into four groups (n = 8): (a) Con: control; (b) Met: 2.5% methionine diet; (c) OVX + Met: ovariectomy + 2.5% methionine diet; (d) OVX + Met + GST: ovariectomy + 2.5% methionine diet + supplementation with genistein. After 12 wk of different treatment, the rats' blood, toracic aortas and liver samples were collected for analysis. Results showed that high-methionine diet induced both elevation of plasma Hcy and endothelial dysfunction, and ovariectomy deteriorated these injuries. Significant improvement of both functional and morphological changes of vascular endothelium was observed in OVX + Met + GST group; meanwhile the plasma Hcy levels decreased remarkably. There were significant elevations of plasma ET-1 and liver MDA levels in ovariectomized HHcy rats, and supplementation with genistein could attenuate these changes. These results implied that genistein could lower the elevated Hcy levels, and prevent the development of endothelial impairment in ovariectomized HHcy rats. This finding may shed a novel light on the anti-atherogenic activities of genistein in HHcy patients.

Upregulation of cytochrome P450 2J3/11,12-epoxyeicosatrienoic acid inhibits apoptosis in neonatal rat cardiomyocytes by a caspase-dependent pathway.

Short, nonlethal ischemic episodes administered to hearts directly after ischemic events (ischemic postconditioning, IPost) have an advantage over ischemic preconditioning (IPC). The endogenous cytochrome P450 2J3/11,12-epoxyeicosatrienoic acid (CYP2J3/11,12-EET) is upregulated by IPost, but not IPC, in the rat heart. The CYP epoxygenase inhibitor N-methylsulphonyl-6-(2-propargyloxyphenyl) hexanamide (MS-PPOH) reduces the cardioprotective effects of IPost, but not IPC. We proposed that upregulation of CYP2J3/11,12-EET during IPost induces cardioprotection by inhibiting cardiomyocyte apoptosis and that multiple apoptotic signals, including changes in mitochondrial membrane potential (MMP) and mitochondrial permeability transition pore (mPTP) opening, mitochondrial cytochrome c leakage, caspase-3 levels, and levels of protective kinases such as Bcl-2 and Bax, are involved in the process. Neonatal rat cardiomyocytes underwent 3-h hypoxia followed by 2-, 5-, or 6-h reoxygenation (H/R) or three cycles of 5-min reoxygenation followed by 5-min hypoxia before 90-min reoxygenation (HPost); or were transfected with pcDNA3.1-CYP2J3 for 48 h before H/R; or were treated with MS-PPOH for 10 min before HPost. For HPost alone, pcDNA3.1-CYP2J3 transfection attenuated cardiomyocyte apoptosis to 68.4% (p<0.05) of that with H/R. pcDNA3.1-CYP2J3 transfection significantly decreased MMP and inhibited mPTP opening induced by H/R, reduced mitochondrial cytochrome c leakage, cleaved caspase-3 protein expression, and increased the ratio of Bcl-2 to Bax expression. MS-PPOH abolished this effect. Therefore, upregulation of CYP2J3/11,12-EET during HPost is involved in cardioprotection by inhibiting apoptosis via a caspase-dependent pathway, and the apoptosis-suppressive effect may have important clinical implications during HPost.

Cytochrome P450 2J3/epoxyeicosatrienoic acids mediate the cardioprotection induced by ischaemic post-conditioning, but not preconditioning, in the rat.

1. Cytochrome P450 (CYP) epoxygenases and their arachidonic acid metabolites play a protective role against ischaemia-reperfusion injury. In the present study, we investigated whether endogenous CYP2J3/epoxyeicosatrienoic acid (EET) mediates the cardioprotective effects of ischaemic preconditioning (IPC) and ischaemic post-conditioning (IPost). 2. Male Wistar rats were subjected to two cycles of IPC, consisting of 5 min ischaemia and 5 min reperfusion, followed by 45 min occlusion and 2 h reperfusion; IPost consisted of three cycles of 30 s reperfusion and 30 s re-occlusion at the onset of reperfusion. The selective CYP epoxygenase inhibitor N-methylsulphonyl-6-(2-propargyloxyphenyl)hexanamide (MS-PPOH; 3 mg/kg) was administered 10 min before ischaemia or during ischaemia 10 min before reperfusion started. Cardiac function was measured continuously with a angiocatheter connected to a fluid-filled pressure transducer and myocardial infarct size was assessed by triphenyl tetrazolium chloride staining at the end of the experiment. 3. Subjecting rats to IPC and IPost similarly improved cardiac function and reduced myocardial infarct size. Interestingly, IPost, but not IPC, significantly increased CYP2J3 mRNA (1.75 ± 0.22 vs 1.0; P < 0.05) and protein (1.62 ± 0.22 vs 1.0; P < 0.05), as well as 11,12-EET synthesis compared to I/R (6.2 ± 0.2 vs 2.9 ± 0.2 ng/mg wet weight, respectively; P < 0.01). Administration of MS-PPOH before ischaemia significantly decreased 11,12-EET synthesis in both IPC and IPost compared with I/R rats (2.1 ± 0.2, 3.2 ± 0.3 and 2.9 ± 0.2 ng/mg wet weight, respectively; P < 0.01), but decreased the cardioprotective effects, as evidenced by cardiac function and myocardial infarct size, of IPost only. 4. These data indicate that endogenous activation of CYP2J3/EET may be an essential trigger leading to the protective effects of IPost, but not IPC, in the rat heart.

Age-related up-regulation of beta3-adrenergic receptor in heart-failure rats.

Stimulation of beta1- and beta2-adrenergic receptors (ARs) in the heart results in positive inotropy. In contrast, it has been reported that the beta3-AR is also expressed in the heart and that its stimulation leads to negative inotropic effects. The aim of this study was to investigate the expression of beta3-AR in age-related heart-failure rats and its relevance to left ventricular dysfunction. Aging male Wistar rats were divided into young and aging groups according to age, and each group included sham-operation and heart-failure subgroups. Left ventricular end-diastolic pressure (LVEDP) and the ratio of left ventricular weight to body weight (LV/BW) were significantly higher for the aging heart-failure versus young heart-failure and the heart-failure versus sham-operation groups (P < 0.01, respectively). However, the left ventricular end-systolic pressure (LVESP) and the maximal rate of rise or fall of left ventricular pressure were all significantly lower for the aging heart-failure versus young heart-failure and the heart-failure versus sham-operation groups (P < 0.01, respectively). beta3-AR protein levels increased significantly when heart failure worsened in aging rats. These results suggest that beta3-AR expression in age-related heart-failure rats and left ventricular function were highly correlated.

[Dynamic extraction process of salvianolic acids].

OBJECTIVE: To optimize the dynamic extraction process of salvianolic acids. METHOD: Salvianolic acids was selected as index. The effects of extraction temperature, granularity, solvent multiple, circle value and extraction time were studied on the process of dynamical extraction. The orthogonal experiment was employed to investigate the influence of different parameters. RESULT: The optimal extracting method of salvianolic acids was as follows: temperature was 80 degrees C, granularity was 4 mm, circle value was 30 L x h(-1), solvent multiple was 10 times and extraction time was 150 min. CONCLUSION: By comparison to static extraction, dynamic extraction can improve the extraction efficiency, reduce the solvent and energy consumption, as well as lower the burden of post-processing.

Neuregulin-1 preconditioning protects the heart against ischemia/reperfusion injury through a PI3K/Akt-dependent mechanism.

BACKGROUND: Neuregulin-1 (NRG-1), the ligand of the myocardial ErbB receptor, is a protein mediator with regulatory actions in the heart. This study investigated whether NRG-1 preconditioning has protective effects on myocardial ischemia/reperfusion (I/R) injury and its potential mechanism. METHODS: We worked with an in vivo rat model with induced myocardial ischemia (45 minutes) followed by reperfusion (3 hours). NRG-1 message was detected in the heart using RT-PCR and the protein levels of NRG-1 and ErbB4 were detected by Western blotting analysis. Infarct size was assessed using the staining agent triphenyltetrazolium chloride and cardiac function was continuously monitored. The levels of creatine kinase and lactate dehydrogenase in plasma were analyzed to assess the degree of cardiac injury. The extent of cardiac apoptosis was evaluated by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay and by Western blotting analysis of cleaved caspase-3. We examined the phosphorylation of Akt in the myocardium and the effect of PI3K/Akt inhibition on NRG-1-induced cardioprotection. RESULTS: Transcription and expression of NRG-1 and phosphorylation of its ErbB4 receptor were significantly upregulated in the I/R hearts. NRG-1 pretreatment reduced the infarct size following cardiac I/R in a concentration-dependent manner with an optimal concentration of 4 µg/kg in vivo. NRG-1 pretreatment with 4 µg/kg, i.v. markedly reduced the plasma creatine kinase and lactate dehydrogenase levels. Pretreatment with NRG-1 also significantly reduced the percentage of TUNEL positive myocytes and the level of cleaved caspase-3 in the I/R hearts. Pretreatment with NRG-1 significantly increased phosphorylation of Akt following I/R. Furthermore, the cardioprotective effect limiting the infarct size that was induced by NRG-1 was abolished by co-administration of the PI3K inhibitor LY294002. CONCLUSIONS: The concentration of NRG-1, a new autacoid, was rapidly upregulated after myocardial I/R. NRG-1 preconditioning has cardioprotective effects against I/R injury through a PI3K/Akt-dependent mechanism in vivo.

Cardioprotective effects of anesthetic preconditioning in rats with ischemia-reperfusion injury: propofol versus isoflurane.

OBJECTIVE: We compare the cardioprotective effects of anesthetic preconditioning by propofol and/or isoflurane in rats with ischemia-reperfusion injury. METHODS: Male adult Wistar rats were subjected to 60 min of anterior descending coronary artery occlusion followed by 120 min of reperfusion. Before the long ischemia, anesthetics were administered twice for 10 min followed by 5 min washout. Isoflurane was inhaled at 1 MAC (0.016) in I group, whereas propofol was inhaled intravenously at 37.5 mg/(kg(h) in P group. A combination of isoflurane and propofol was administered simultaneously in I+P group. RESULTS: In control (without anesthetic preconditioning, C group), remarkable myocardial infarction and apoptosis accompanied by an increased level of cardiac troponin T were noted 120 min after ischemia-reperfusion. As compared to those of control group, I and P groups had comparable cardioprotection. In addition, I+P group shares with I and P groups the comparable cardioprotective effects in terms of myocardial infarction and cardiac troponin T elevation. CONCLUSION: A combination of isoflurane and propofol produced no additional cardioprotection.

[Protective effects of 11,12-epoxyeicosatrienoic acid preconditioning and postconditioning on myocardial ischemia/reperfusion injury in rats].

To explore the effects of 11,12-epoxyeicosatrienoic acid (11,12-EET) preconditioning and postconditioning on myocardial ischemia/reperfusion (IR) injury in rats, the IR injury model was built by stopping perfusion for 40 min followed by reperfusion for 30 min, and the changes of mitochondrial functions, myocardial metabolism and function were measured. Langendorff-perfused isolated rat hearts were divided into 4 groups: control group, persistently perfused with Krebs-Henseleit (K-H) fluid for 100 min; IR group, stopped perfusion for 40 min followed by reperfusion for 30 min; Pre-EET group, preconditioned with 6.24×10(-9) mol/L 11,12-EET for 5 min twice before subjected to ischemia; Post-EET group, postconditioned with 6.24×10(-9) mol/L 11,12-EET for 30 s twice before reperfusion. The computer-based electrophysiological recording system was used to measure the changes of maximal rate of the pressure increase in contract phase (+dp/dt(max)), maximal rate of the pressure decrease in diastole phase of heart (-dp/dt(max)), left ventricular end-diastolic pressure (LVEDP) and difference of left ventricular pressure (DLVP). The activities of lactate dehydrogenase (LDH) in effluent, Ca(2+)-ATPase, Na(+)-K(+)-ATPase and succinate dehydrogenase (SDH) in mitochondria were measured with colorimetry method; superoxide dismutase (SOD) activity was measured with hydroxylamine method and malondialdehyde (MDA) content in myocardial tissues was measured with TBA method. The results showed that: (1) Compared with that in the control group, the myocardial functions, the values of SOD, SDH and Na(+)-K(+)-ATPase were decreased in IR group (P<0.05); the values of LDH, MDA and Ca(2+)-ATPase were increased (P<0.05) in IR group. (2) Compared with that in IR group, the values of SDH and Na(+)-K(+)-ATPase were increased (P<0.05) and the value of Ca(2+)-ATPase was decreased (P<0.05) in both Pre-EET and Post-EET groups. But no significant differences were detected between Pre-EET and Post-EET groups. (3) Compared with IR treatment, both 11,12-EET preconditioning and postconditioning caused significant decreases in MDA content and leakage of LDH, amendment of heart functions and increases in SOD activity (P<0.05). But there were no significant differences between 11,12-EET preconditioning and postconditioning. These results indicate that 11,12-EET preconditioning and postconditioning can protect myocardium from IR injury by improving mitochondrial functions, up-regulating the activities of Na(+)-K(+)-ATPase and SDH, and down-regulating the activity of Ca(2+)-ATPase in mitochondria. Moreover, 11,12-EET preconditioning and postconditioning also elevate the activity of SOD and reduce the content of MDA, suggesting that 11,12-EET can depress the oxidative stress in IR rat heart.

[Effects of 11, 12-epoxyeicosatrienoic acid preconditioning and postconditioning on Ca(2+)- handling proteins in myocardial ischemia/reperfusion injury in rats].

OBJECTIVE: To investigate the effects of 11, 12-epoxyeicosatrienoic acid (11, 12-EET) preconditioning and postconditioning on Ca(2+)-handling proteins in myocardial ischemia/reperfusion (IR) injury in rats and reveal the effects and mechanism of 11, 12-EET on cardioprotection. METHODS The IR injury model was built by stopping perfusion for 40 minutes followed by reperfusion for 30 minutes. The isolated Langendorff-perfused rat hearts were divided into 4 groups: control group, IR group, EET preconditioning (Pre-EET) group and EET postconditioning (Post-EET) group. The computer-based electrophysiological recorder system was used to measure the changes of the maximal rate of pressure increased in the contraction phase (+dp/dt(max)), the maximal rate of pressure decreased in the diastole phase (-dp/dt(max)), the left ventricular end diastolic pressure (LVEDP) and the difference of left ventricular pressure (delta LVP). The activity of Ca(2+)-ATPase in sarcoplasmic reticulum was measured with colorimetric method. Reverse transcription-polymerase chain reaction was used to assess the gene expression of C(a2+)-handling protein [sarcoplasic reticulum Ca(2+)-ATPase (SERCA), phospholamban (PLB), ryanodine receptor type 2 (RyR,), and 1, 4, 5-trisphosphate inositol receptor type 2 (IP3 R2) ] mRNAs level. RESULTS: Compared with IR group, the myocardial functions, the value of Ca(2+)-ATPase, and the expressions of IP3 R2 mRNA were significantly increased and the expression of PLB mRNA was significantly decreased in both Pre-EET group and Post-EET group (P < 0.05, P < 0.01). And the expression of SERCA mRNA was significantly increased in Pre-EET group (P < 0. 05). However, no significant differences were detected between Pre-EET and Post-EET groups. Moreover, the expression of RyR2 mRNA was not significantly different among all groups. CONCLUSIONS: 11, 12-EET preconditioning and post-conditioning can protect myocardium from IR injury by elevating the activity of Ca(2+)-ATPase in sarcoplasmic reticulum, up-regulating the expression of IP3 R2 mRNA, and down-regulating the expression of PLB mRNA. Moreover, up-regulating the expression of SERCA mRNA maybe one of mechanisms of 11, 12-EET preconditioning on cardio protection against IR injury.

[Effect of 11, 12-epoxyeicosatrienoic acids on hypoxia/reoxygenation injury in the human umbilical vein endothelial cells].

OBJECTIVE: To investigate the effects of 11, 12-epoxyeicosatrienoic acids (11, 12-EET) on the degree of hypoxia/reoxygenation injury in human umbilical vein endothelial cells ( HUVECs), and reveal the possible pathway of EET on protection. METHODS: Primary cultured HUVECs were randomly divided into control group, hypoxia/reoxygenation group, 11, 12-EET control group, 11, 12- EET hypoxia/reoxygenation group, inhibition of extracellular signal-regulated kinase (ERKI/2) group, and inhibition of nitric oxide synthase (NOS) group. Hypoxia/reoxygenation injury model in HUVECs was established by exposure to hypoxia (2% O2, 5% CO2 and 93% N2) for 3 hours, followed by reoxygenation (95% air and 5% CO2) for 1 hour. The evaluation of the endothelial cells were made by immunohistochemistry. The cell viability was monitored by MTT assay. Colorimetry method was used to assay the lactate dehydrogenase (LDH) , malondialdehyde (MDA) and activity of superoxide dismutase (SOD) in culture medium. Western blot was used to detect the expressions of endothelial nitric oxide synthase (eNOS) and phosphorylated ERK1/2 in HUVECs. RESULTS: 11, 12-EET caused minor injury in normal oxygen incubated HUVECs; however, in hypoxia/reoxygenation HUVECs, it raised the cell viability markedly, decreased the LDH release and MDA content, and increased the activity of SOD and the expressions of eNOS and phosphorylated ERK1/2. CONCLUSIONS: 11, 12-EET may prevent against endothelial cell hypoxia/reoxygenation injury. The mechanism may be related to the increased activity of SOD, elimination of oxygen-derived free radicals, and reduction of eNOS and phosphorylated ERK1/2 lesion caused by hypoxia/reoxygenation.

[Effect of 11, 12-epoxyeicosatrienoic acid on nitric oxide synthase of ischemia-reperfusion myocardium in rats].

OBJECTIVE: To observe the effect of 11,12-epoxyeicosatrienoic acid (11,12-EET) on nitric oxide synthase (NOS) in myocardial ischemia/reperfusion injury and explore the protective role of NOS in myocardium. METHODS: Rat myocardial ischemia/reperfusion model was produced by ischemia for 60 minutes and reperfusion for 30 minutes. Rats were divided into 5 groups: 11,12-EET ischemia/reperfusion groups (including EET1, EET2, and EET3 groups), EET control group, ischemia/reperfusion group, sham operation group, and control group. Changes of the maximal rates of rise and decrease of left ventricular pressure (+/-dp/dtmax) were observed. Activities of inducible nitric oxide synthase (iNOS) and constrictive nitric oxide synthase (cNOS) in myocardium were measured with chemocolorimetry. RESULTS: During both ischemia period (60 min) and reperfusion period (30 min), +/-dp/dtmax was significantly lower in ischemia/reperfusion group than in sham operation group (P < 0.01), and was significantly higher in EET1, EET2 and EET3 groups than in ischemia/reperfusion group (P < 0.01). cNOS level was significantly lower in ischemia/reperfusion group than in sham operation group, was significantly higher in EET1, EET2 and EET3 groups than in sham operation group (P < 0.01), and was significantly higher in EET2 group than in EET group (P < 0.01). iNOS level was significantly higher in sham operation group than in EET control group (P < 0.05), was significantly higher in ischemia/ reperfusion group than in sham operation group (P < 0.01), and was significantly lower in EET1, EET2 and EET3 groups than in ischemia/reperfusion group (P < 0.01). CONCLUSION: Exogenous 11,12-EET can improve ischemia/reperfusion injury, which may be related with the changes of NOS isozymes.