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The purpose of the present study was to examine the effects of oxidative stress on ventricular arrhythmias in rabbits with adriamycin-induced cardiomyopathy and the relationship between oxidative stress and ventricular arrhythmia. Forty Japanese white rabbits were randomly divided into four groups (n=10 in each): control group, metoprolol (a selective β1 receptor blocker) group, carvedilol (a nonselective β blocker/α-1 blocker) group and adriamycin group. Models of adriamycin-induced cardiomyopathy were established by intravenously injecting adriamycin hydrochloride (1 mg/kg) to rabbits via the auri-edge vein twice a week for 8 weeks in the adriamycin, metoprolol and carvedilol groups. Rabbits in the control group were given equal volume of saline through the auri-edge vein. Rabbits in the metoprolol and carvedilol groups were then intragastrically administrated metoprolol (5 mg/kg/d) and carvedilol (5 mg/kg/d) respectively for 2 months, while those in the adriamycin and control groups were treated with equal volume of saline in the same manner as in the metroprolol and carvedilol groups. Left ventricular end diastolic diameter (LVEDd) and left ventricular ejection fraction (LVEF) were measured by echocardiography. Plasma levels of N-terminal pro B-type natriuretic peptide (NT-proBNP), malondialdehyde (MAD) and superoxide dismutase (SOD) were detected. The left ventricular wedge preparations were perfused with Tyrode's solution. The transmural electrocardiogram, transmural action potentials from epicardium (Epi) and endocardium (Endo), transmural repolarization dispersion (TDR) were recorded, and the incidences of triggered activity and ventricular arrhythmias were obtained at rapid cycle lengths. The results showed that TDR and the serum MDA and NT-proBNP levels were increased, and LVEF and the serum SOD level decreased in the adriamycin group compared with the control group. The incidences of triggered activity and ventricular arrhythmia were significantly higher in the adriamycin group than those in the control group (P<0.05). In the carvedilol group as compared with the adriamycin group, the serum SOD level and the LVEF were substantially increased; the TDR, and the serum MDA and NT-proBNP levels were significantly decreased; the incidences of triggered activity and ventricular arrhythmia were obviously reduced (P<0.05). There were no significant differences in the levels of MDA and SOD, LVEF, TDR and the incidences of triggered activity and ventricular arrhythmia between the adriamycin group and the metoprolol group. It was concluded that carvedilol may inhibit triggered activity and ventricular arrhythmias in rabbit with adriamycin-induced cardiomyopathy, which is related to the decrease in oxygen free radials.
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Animais , Masculino , Coelhos , Antiarrítmicos , Antibióticos Antineoplásicos , Carbazóis , Cardiomiopatias , Doxorrubicina , Frequência Cardíaca , Metoprolol , Estresse Oxidativo , Propanolaminas , Resultado do Tratamento , Fibrilação VentricularRESUMO
The purpose of the present study was to examine the effects of oxidative stress on ventricular arrhythmias in rabbits with adriamycin-induced cardiomyopathy and the relationship between oxidative stress and ventricular arrhythmia. Forty Japanese white rabbits were randomly divided into four groups (n=10 in each): control group, metoprolol (a selective β1 receptor blocker) group, carvedilol (a nonselective β blocker/α-1 blocker) group and adriamycin group. Models of adriamycin-induced cardiomyopathy were established by intravenously injecting adriamycin hydrochloride (1 mg/kg) to rabbits via the auri-edge vein twice a week for 8 weeks in the adriamycin, metoprolol and carvedilol groups. Rabbits in the control group were given equal volume of saline through the auri-edge vein. Rabbits in the metoprolol and carvedilol groups were then intragastrically administrated metoprolol (5 mg/kg/d) and carvedilol (5 mg/kg/d) respectively for 2 months, while those in the adriamycin and control groups were treated with equal volume of saline in the same manner as in the metroprolol and carvedilol groups. Left ventricular end diastolic diameter (LVEDd) and left ventricular ejection fraction (LVEF) were measured by echocardiography. Plasma levels of N-terminal pro B-type natriuretic peptide (NT-proBNP), malondialdehyde (MAD) and superoxide dismutase (SOD) were detected. The left ventricular wedge preparations were perfused with Tyrode's solution. The transmural electrocardiogram, transmural action potentials from epicardium (Epi) and endocardium (Endo), transmural repolarization dispersion (TDR) were recorded, and the incidences of triggered activity and ventricular arrhythmias were obtained at rapid cycle lengths. The results showed that TDR and the serum MDA and NT-proBNP levels were increased, and LVEF and the serum SOD level decreased in the adriamycin group compared with the control group. The incidences of triggered activity and ventricular arrhythmia were significantly higher in the adriamycin group than those in the control group (P<0.05). In the carvedilol group as compared with the adriamycin group, the serum SOD level and the LVEF were substantially increased; the TDR, and the serum MDA and NT-proBNP levels were significantly decreased; the incidences of triggered activity and ventricular arrhythmia were obviously reduced (P<0.05). There were no significant differences in the levels of MDA and SOD, LVEF, TDR and the incidences of triggered activity and ventricular arrhythmia between the adriamycin group and the metoprolol group. It was concluded that carvedilol may inhibit triggered activity and ventricular arrhythmias in rabbit with adriamycin-induced cardiomyopathy, which is related to the decrease in oxygen free radials.
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Pim kinases contribute to tumor formation and development of lymphoma, which shows enhanced DNA replication, DNA recombination and repair. Endothelial cells
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In order to investigate the influence of silencing soluble epoxide hydrolase (sEH) with double-stranded small interfering RNA (siRNA) on cardiomyocytes apoptosis induced by doxorubicin (DOX), two plasmids containing siRNA sequences specific to sEH were constructed and transfected into the primary cultured cardiomyocytes by using FuGENE HD transfection agents. The mRNA and protein expression levels of sEH were detected by semiquantitative RT-PCR and Western blotting respectively, and the plasmids that silenced sEH most significantly were selected, and renamed EH-R. The plasmids carrying a nonspecific siRNA coding sequence (PCN) served as the negative control. Cardiomyocytes were divided into four groups: control group, DOX group, PCN+DOX group, and EH-R+DOX group. Apoptosis of cardiomyocytes was induced by DOX at a concentration of 1 μmol/L. Apoptosis rate of cardiomyocytes was determined by flow cytometery. The protein expression levels of Bcl-2 and Bax were detected by Western blotting. The results showed that the expression of sEH was down-regulated by EH-R plasmid. The expression levels of sEH mRNA and protein in the EH-R+DOX group were significantly decreased as compared with other groups (P<0.01). As compared with the control group, the apoptosis rate of cardiomyocytes in three DOX-treated groups was obviously increased, the expression levels of Bax increased, and those of Bcl-2 decreased (P<0.01). However, the expression levels of Bax were decreased, those of Bcl-2 increased and the apoptosis rate of cardiomyocytes obviously decreased in EH-R+DOX group when compared with those in the DOX group and the PCN+DOX group (P<0.01 for each). It was concluded that the recombinant plasmids could be successfully constructed, and transfected into the primary cultured cardiomyocytes. They could ameliorate the DOX-induced cardiomyocytes apoptosis by selectively inhibiting the expression of sEH with RNAi and increasing the expression of Bcl-2.
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Plaque rupture,platelet aggregation,and thrombogenesis are the main mechanisms of acute coronary syndrome (ACS),and inflammation factors play key roles in plaque unstability.Psychological stress promotes acute inflammatory response,leading to increased circulating levels of C-reactive protein (CRP),IL-6,and serum intercellular adhesion molecule (sICAM)-1.But it is not clear that whether psychological stress has a direct effect on atherosclerotic plaque stability.The purpose of this study was to investigate effects of chronic psychological stress on inflammatory marker (ICAM-1 ) in atherosclerotic plaque,and inflammatory markers in peripheral blood.Materials and methods Sixty male rabbits were randomized into 2 groups:the control group (n =10) and the atherosclerotic group (n =50).The latter were fed on high fatty diet and were given a large dose of vitamin D3 (3 600 000IU/kg) via intraperitoneal injection.After 8 weeks,the atherosclerotic model was estaslished.Then the 50 atherosclerotic model rabbits were divided into 3 subgroups:no-stress subgroup (n = 16),physiological stress subgroup (n = 16) and psychological stress subgroup (n =18).In physiological stress subgroup and psychological stress subgroup,drinking was cut from twice a day to once a day.At the same time,psychological stress subgroup was given empty bottle stress,and this process lasted for 2 weeks.One hour after the last stress,the blood samples were collected and the serum levels of CRP,IL-6 amd ICAM-1 were tested by radioimmunoassay or enzyme linked immunosorbent assay.The aorta and heart were extracted for pathology examination,and the express of ICAM-1 was tested by immunohistochemical examination.Results (1) After effective atherosclerotic animal model construction,the expression of ICAM-1 in aorta was higher in atherosclerotic group than that in control group (P＜0.01),and was notably higher in psychological stress subgroup than that in no-stress subgroup or in physiological stress subgroup (2.18±0.17 vs 1.58±0.22,1.22±0.15,P＜0.001,respectively).The expression in physiological stress subgroup was higher than that in no-stress subgroup (584±0.22 vs 1.22±0.15,P=0.001).(2) The serum level of IL-6 (51.80±4.60 pg/ml vs 27.60±4.19 pg/ml,8.01±1.39 pg/ml,7.83±1.37 pg/ml),sICAM-1 ( 1.24±0.25 vs 0.85±0.09,0.62±0.17,0.57±0.11),CRP ( 1.004±0.37 vs 0.90±0.29,1.01±0.22,0.71±0.13) in psychological stress group were significantly higher than that in other groups (All P＜0.05).There was a positive relationship between the serum level of CRP,IL-6 and ICAM-1 and the expression of ICAM-1 in aorta wall ( r =0.59,r =0.75,r =0.87,P＜0.01,respectively).Conclusions Psychological stress induces an increased expression of ICAM-1 in aortic atherosclerotic plaque,a higher serum level of CRP,IL-6,and sICAM-1 expression.Psychologial stress has a direct effect on the transition from stability to unstability through in-plaque and out-plaque inflammation.The serum level of CRP,IL-6 and ICAM-1 can reflex the inflammatory degree in atherosclerotic plaque.(J Geriatr Cardiol 2008;5:235-242)
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Intracellular Ca2+ and Ca2+-dependent signaling molecule play an essential role in the genesis of long-QT (LQT) syndrome-related ventricular arrhythmias. The effect of calcium-channel antagonist verapamil on repolarization heterogeneity of ventricular myocardium was assessed in an in vitro rabbit model of LQT syndrome. By using the monophasic action potential (MAP) recording technique, MAPs of epicardium, mid-myocardium and endocardium were simultaneously recorded by specially designed plunge-needle electrodes across the left ventricular free wall in rabbit hearts purfused by Langendorff method with standard Tyrode's solution. Bradycardia was induced by com-plete ablation of atrioventrtcular node. A catheter was introduced into the right ventricle to pace at the cycle lengths (CLs) of 1500, 1000, and 500 ms, successively. Quinidine (2 μol/L) prolonged QT in-terval and ventricular MAP duration (MAPD), and increased transmural dispersion of repolarization (TDR) in a reverse rate-dependent fashion in isolated rabbit heart. No polymorphic ventricular tachycardias were induced under this condition. The effective free therapeutic plasma concentrations of verapamil (0.01-0.05 μmol/L) used in this experiment had no effect on quinidine-induced changes of QT interval, MAPD and TDR. This study demonstrated that, in this model of LQT syn- drome, blockade of calcium-channel with verapmil had no effect on quinidine-induced changes of repolatiation heterogeneity of ventricular myocardium.
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BACKGROUND: Peroxisome proliferation-activated receptor-gamma (PPARγ) is the member of nuclear receptor superfamily, and closely related with the formation of atherosclerosis.OBJECTIVE: To investigate the relationship between PPARγ C161→T gene polymorphism and coronary atherosclerotic heart disease (CAHD).DESIGN: Randomized controlled experiment SETTING: Department of Cardiology, Tonai Hospital of Huazhong University of Science and Technology; Department of Cardiology, Zhongnan Hospital of Wuhan University; Center for Human Genome Research,Huazhong University of Science and Technology; Department of Internal Medicine, Affiliated Hospital of Hubei University of Traditional Chinese Medicine; Institute of Geriatrics, Dongzhimen Hospital, Beijing University of Chinese Medicine PARTICIPANTS: Totally 203 CAHD patients aged (65±11) years, including 129 males and 74 females, were the inpatients and outpatients of Zhongnan Hospital of Wuhan University and Tonai Hospital of Huazhong University of Science and Technology from June 2002 to December 2005.And 156 cases of them were diagnosed by coronary arteriongraphy, among which 43 patients without coronary artery affection or with coronary stricture ＜ 50%, and 113 patients with coronary stricture ＞ 50 %. While 89 healthy physical examinees of Han race and mean (59±9) years old were enrolled as control group, including 56 males and 33 females. There was no blood relationship between controls and patients.METHODS: The experiment was conducted at Tongji Hospital of Huazhong University of Science and Technology from June 2002 to December 2005. PPARγ C161→T gene polymorphism was determined by polymerase chain reaction and restriction endonuclease fragment length polymorphisms. The radio-immunity technique, coronary angiography and clinical routine biochemical index were applied to analyze the genotypic frequency and allele frequency distributions as well as the relation between clinical data, biochemical index and different genotypes. The risk factors of CAHD were estimated in the patients of different genotypes.MAIN OUTCOME MEASURES: The genotypic frequency and allele frequency distributions, the relation between clinical data, biochemical index and different genotypes, along with the blood lipid, blood glucose, fasting insulin and body mass index (BMI).RESULTS: Totally 103 CAHD patients and 89 controls were involved in the result analysis of gene polymorphism and yielded different gene distribution frequencies.① In control group, "T" allele frequency was 0.213 and "C" allele frequency was 0.787, and in CAHD group, "T" allele frequency was 0.192 and "C" allele frequency was 0.808. There was no significant difference in the genotypic frequency and C, T allele frequencies between two groups (P ＞ 0.05).② The CC genotype was dominant in CAHD patients with coronary artery lesions, and showed significant differences from "T"allele carriers (CT+TT) (P ＜ 0.05). The CAHD risk in the "T" allele carries (OR: 0.56, 95% CI: 0.24-0.63) was much lower than that in the CC homozygote (OR: 1.92, 95% CI: 1.09-2.54).③ Apolipoprotein B in patients with CC genotype was obviously higher than that in patients with "T" allele (CT+TT) (P ＜ 0.05), and there was insignificant difference in the insulin resistance index (P ＞ 0.05).CONCLUSION: There is an important correlation between the substitution of PPARγ C161→T and CAHD, and "T" allele carriers demonstrate a lower risk of CAHD.
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BACKGROUND: Mesenchymal stem cells (MSCs) can differentiate into myocardial cells in vitro and in vivo, but the amount is small and directed differentiation rate is low.OBJECTIVE: To explore the effect of stem cell factor (SCF) on promotion of MSCs differentiating into myocardial cells.DESIGN: Opening experiment.SETTING: Institute of Cardiovascular Disease, Xianning College and Department of Cardiology, Tongji Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology.MATERIALS: The experiment was performed at the Experimental Center of Institute of Cardiovascular Disease, Xianning College from October 2003to August 2004. A total of 20 infant SD rats aged 1-2 days were selected for culture of myocardial cells. Another 25 clean adult SD rats were selected and randomly divided into SCF group, blank control group with 12 rats in each group. The left one rat was used for MSCs extraction, culture and purification.METHODS: ①MSCs were labeled with 4', 6-diamidino-2-phenylindole,dihydrochloride (DAPI) before co-culture. SCF was given into rats of the SCF group by subcutaneous injection successively for 5 days, 20 μg/kg per day. Isolated MSCs were co-cultured with myocardial cells that had been cultured for 3 days. Saline of the same volume was given in the blank control group by subcutaneous injection. MSCs without any intervention were co-cultured with myocardial cells that had been cultured for 3 days.②Expressions of MHC α/β and troponin T were recorded and measured with digital micro-camera shot and immunofluorescence technique, respectively. Percentage of DAPI labeled MSCs differentiating into myocardial cells was measured.MAIN OUTCOME MEASURES: ①Growth of MSCs, ②detection of labeling rate of DAPI on MSCs, ③analysis of activity and purity of co-cultured myocardial cells, and ④differentiation of MSCs into myocardial cells after co-culture.RESULTS: ①Bone marrow cell suspension was inoculated in plastic petri dish. Round cells scattered at the bottom of bottle. At hour 24 a few long fusiform shape adhered cells appeared following liquor change, and at day 4 many fusiform shape adhered cells appeared, which entered logarithm increased period. At days 8-12 80% were confluence. The proliferation of passage cells was more rapid. With liquor change and passage, the MSCs were purified gradually. ②Labeling rate of DAPI on MSCs was 100%. ③At 3-day in vitro culture of myocardial cells the percentage of beat cells was 63%, with beat frequency of 40-60 times per minute. Percentage of positive cells of troponin T expression was 75% examined with immunocytochemical technique. ④At co-cultured days 2 and 3, positive percentage of DAPI labeled MSCs expressing MHC α/β was significantly higher in the SCF group than in the blank control group (P ＜ 0.01). At the co-cultured days 3, 4 and 5, positive percentage of DAPI labeled MSCs expressing troponin T was obviously higher in the SCF group than in the blank control group (P ＜ 0.01).CONCLUSION: SCF has markedly accelerating effect on proliferation and differentiation of MSCs.
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Aim To explore the effects of lipoteichoic acid (LTA) induced delayed preconditioning (PC) on hypoxia-reoxygenation (H/R) injury of cultured human coronary artery endothelial cells (HCAECs), and to investigate the potential role of endogenous nitric oxide (NO) participated in the protective mechanism. Methods HCAECs were incubated for 2 h in a hypoxic atmosphere and reoxygenated for 4 h in a normoxic atmosphere. The delayed PC was induced by pretreatment with LTA assessed by the percentage of cellular injury with Trypan blue exclusion and by the amount of lactate dehydrogenase (LDH) in culture media. The NO level of the culture media was measured detect the expression of eNOS mRNA by RT-PCR method after cells were recovered from different points.Results LTA pretreatment significantly decreased the percentage of the killed cell and the concentration of LDH in media. Also, LTA pretreatment obviously raised the concentrations of NO in culture media. The protective effects of LTA were abrogated by pretreatment with N-monomethyl-L-arginine (L-NMMA).Moreover, the expression of eNOS mRNA was significantly upregulated after HCAECs exposure to LTA for 4 h following 2 h or 4 h recovery. Conclusion LTA could induce the delayed protection against H/R induced endothelial injury and dysfunction of cultured HCAECs. NO produced by eNOS acts initially as a trigger and subsequently as a mediator of delayed PC.
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The transmural heterogeneous changes of transient outward potassium currents (Ito) in rabbit hypertrophic cardiaomyocytes and the effects of long-term prophylactic treatment with volsartan were investigated. Rabbits were divided into hypertrophy group (left ventricular hypertrophy induced by partial ligation of abdominal aorta), vol-treated group (volsartan was administrated after the ligation), and control group (sham operated). Myocytes were isolated by a two-step enzymatical method. The sub-endocardial (Endo) and sub-epicardium (Epi) tissues were separated from midmyocardium (Mid) with a razor. Whole-cell patch-clamp technique was used to record potassium currents. The results showed that membrane capacitance was larger in hypertrophic cells than those in control and vol-treated cells (P<0.01 vs control cells, n=30). The densities of Ito in hypertrophic cells were reduced by sub-epicardium (Epi) (27.8 +/- 2.9) %, midmyocardium (Mid) (41.0+/-4.7) %, and sub-endocardium (Endo) (20.3 +/- 3.4) % compared with those in control cells. The decrease of Ito density was more pronounced in Mid than in Epi and Endo (P<0.01 vs Epi or Endo). There were no significant differences in Ito densities between vol-treated group and control group in three layers separately. In conclusion, volsartan can inhibit the transmural heterogeneous changes of Ito in left ventricular hypertrophic cardiomyocytes in rabbit.
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Animais , Feminino , Masculino , Coelhos , Anti-Hipertensivos , Farmacologia , Transporte Biológico Ativo , Hipertrofia Ventricular Esquerda , Tratamento Farmacológico , Patologia , Miócitos Cardíacos , Patologia , Técnicas de Patch-Clamp , Canais de Potássio , Tetrazóis , Farmacologia , Valina , Farmacologia , ValsartanaRESUMO
Objective To investigate the relationship of peroxisome proliferator activated receptor gamma ( PPAR?)C161T gene polymorphism with related diseases of metabolic syndrome. To disscuss the mechanism of the elderly diseases from gene level and the relation between the gene polymorphism and lipid metabolism. Methods Three hundred seventy one non-sibship subjects of Han nationality were investigated in this study, including 69 old healthy subjects, 302 elderly cases diagnosed as metabolic syndrome. PPAR? C161T gene polymorphism was determined by polymerase chain reaction and restriction fragment length polymorphism, and radioimmunoassay was used to detect serum insulin. The insulin resistance was obtained from homeostasis model assessment (HOMA), and blood glucose, blood lipoprotein, height, weight and so on were tested. The frequencies of PPAR? C161T genotypes and the allele were compared with the clinical data. Results (1) In the groups of old normal health and metabolic syndrome, "T" allele frequency was 0.217,0.201, and "C" allele frequency was 0.783, 0.798 . There was no significant difference between the groups. (2)The triglyceride in CC genotypes of the metabolic syndrome was significantly higher than that in "T" allele carriers. Conclusions (1) The distributing trend of PPAR ? C161T gene polymorphism of the Han nationality in Wuhan in the elderly normal healthy group was in accord with that in the group of the elderly metabolic syndrome. (2) PPAR ? C161T substitution can influence metabolic syndrome, especially in liporprotain metabolism. "T" allele is associated with lower level of triglyceride.
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AIM: To investigate the changes of transmural repolarization heterogeneity and ion currents in rabbits with left ventricular hypertrophy. METHODS: Ventricular hypertrophy was induced by a partial constriction of the abdominal aorta in rabbits. Myocytes were isolated by a two steps enzymological method. The sub-endocardial (Endo) and sub-epicardium (Epi) tissues were separated from other region (midmyocardium, Mid) with a razor. Whole cell patch clamp technique was used to record the action potential and ion currents. RESULTS: The action potentials duration at 90% repolarization (APD 90 ) of Epi, Mid and Endo were all prolonged significantly in hypertrophy group compared to control group. This prolongation of APD 90 was more pronounced in Mid (26.0%?2.7%) than that in Epi (14.0%?1.6%) and Endo (10.0%?1.1%). The transmural repolarization heterogeneity was increased significantly in the hypertrophy group. The I Ks and I to density in Epi, Mid and Endo was decreased significantly in hypertrophy group compared to those in control group. This decrease in I Ks and I to density was more pronounced in Mid than in Epi and Endo. No significantly difference of I Ca,L and I Kr density between hypertrophy group and control group in three layers was observed. The I K1 density decreased significantly in hypertrophy group compared to control group, but the extent of the decrease had no differences among the three layers. CONCLUSIONS: The transmural repolarization heterogeneity increases significantly in rabbit hypertrophied ventricle. The decrease in transmural heterogeneity of I to and I Ks is the main causes. [
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AIM: To observe the effect of hemin on the expression of heme oxygenase-1(HO-1) in rat vascular smooth muscle cells(VSMCs). METHODS: Wistar rat aortic VSMCs were cultured in vitro and induced to proliferate by angiotensinⅡ(AngⅡ),hemin(a substrate and inducer of HO-1) and zinc protoporphyrin-Ⅸ(ZnPP,an inhibitor of HO-1)were added to induce and inhibit the expression of HO-1,respectively.The expression of HO-1 mRNA and protein were detected using reverse transcription polymerase chain reaction (RT-PCR)and Western blot,respectively. The relative amount of CO released into the media was quantitated as carbon monoxide hemoglobin(COHb)by enzyme-linked immunosorbent assay(ELISA),the proliferation of VSMCs was detected by MTT. RESULTS: The expression of HO-1 mRNA and protein in VSMCs and the amount of COHb in the media were increased significantly by hemin.Meanwhile the proliferation of VSMCs was suppressed markedly. CONCLUSION: The change of HO-1 mRNA and protein expression is the molecular base of the antiproliferation of endogenous CO .The HO-CO system might play a significant role in the development of cardiovascular diseases characterized by proliferation of VSMCs.
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AIM:To investigate the effect of pretreatment of stem cell factor(SCF) and granulocyte colony-stimulating factor(G-CSF) on the proliferation and the differentiation of mesenchymal stem cells(MSCs) into cardiomyogenic cells.METHODS:The MSCs,isolated primarily from bone marrow,and purified by passage culture,were obtained from the adult rats of four groups:the rats were pretreated by 5 daily injections of SCF;the rats were pretreated with G-CSF;the rats were pretreated with SCF and G-CSF;the rats were treated without any intervention.The 4th passage of MSCs was labeled by DAPI and cellular cycle analysis was conducted by flow cytometry before co-culture.The neonatal rat cardiomyocytes cultured for 3 days were co-cultured with DAPI-MSCs.The percentage of the differentiation of MSCs into cardiomyogenic cells during the five co-culture days was analyzed.The morphologic changes of MSCs and the proteins expression of cardiac myosin heavy chain(MHC) and troponin T(TnT) were recorded respectively with digital microscope camera system and immunofluorescence technique.The percentage of the differentiation of MSCs into cardiomyogenic cells was also calculated.RESULTS:The percentage of MSCs in G0/G1 phase in SCF/G-CSF group was significantly lower than that in SCF group,G-CSF group and the control group.The percentage of MHC protein-positive MSCs in SCF/G-CSF group was markedly higher than that in SCF group,G-CSF group and the control group,and that in SCF group and G-CSF group was significantly higher than control group.The percentage of TnT protein-positive MSCs in SCF/G-CSF group,SCF group and G-CSF group was significantly higher than that in control group.CONCLUSION:SCF and G-CSF show the ability to stimulate the proliferation of MSCs and induce MSCs to differentiate into cardiomyocytes.The combination of using SCF and G-CSF is more effective than using only SCF or G-CSF.
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AIM: To investigate the role of SMADs singal pathway in rat myocardial hypertrophy. METHODS: The rat model of myocardial hypertrophy was produced by constriction of the abdominal aorta. The wet left vertricular/body weight ratio (LVMI) was measured. The expression of TGF-beta l and Smad 2, 3, 7 mRNA were assessed by RT-PCR. RESULTS: The LVMI and the expression of TGF-beta l and Smad 2, 3, 7 mRNA in cardiomyothy were increased in 3 day after the operation and continued at last 4 weeks. The peak expression of TGF-beta l and Smad 2, 3, 7 mRNA was in 2 weeks after operation. The expression of Smad 7 was increased in 3 days after operation, but the peak was in 1 week after operation, then decreased. CONCLUSION: The signal protein Smad 2, 3, 7 are involved in the progress of rat myocardial hypertrophy produced by constriction of abdominal aorta. [
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Adrenomedullin (AM) is a novel vasoactive peptide. The actions of AM include vasodilatation, reduction of arterial pressure, inhibition of vascular smooth muscle cell transference and proliferation, diuretic and natriuretic, inhibition of aldsterone secretion. Furthermore AM modulates extra cellular matrix deposition. So adrenomedullin plays an important role in the regulation of cardiovascular remodeling. This paper reviews the relationship between AM and cardiovascular remodeling.
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AIM: To investigate the effects of TGF-?_1 and signal protein Smad3 on rat cardiac myocyte hypertrophy.METHODS: The total protein was analyzed by flow cytometry and the ANF mRNA expression was measured by RT-PCR to judge the hypertrophy of cultured neonatal cardiac myocytes.Smad3 mRNA expression in cardiac myocytes was measured by RT-PCR,and the protein expression of Smad3 was analyzed by Western blotting.RESULTS: TGF-?_1 significantly increased the total protein in cardiac myocytes and promoted ANF mRNA expression,compared with control group.In cultured neonatal myocytes,AS-ODN of Smad3 inhibited myocyte hypertrophy induced by TGF-?_1.Smad3 mRNA and protein expression increased at 15 min after incubated with TGF-?_1,reached the peak at 1 h,and declined at 4 h.CONCLUSION: TGF-?_1 and signal protein Smad3 may participate in the progress of rat cardiac myocyte hypertrophy.
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AIM: To study the potential effects of lipoteichoic acid (LTA)-induced delayed preconditioning (PC) on cardioplegic arrest/reperfusion injury in donor rat heart. METHODS: The rats were pretreated with LTA (1 mg/kg, ip) 24 h before the experiment, and the isolated hearts were subjected to arrested by cardioplegic solution and stored in Eurocollin's solution for 4 h by the Langendorff method, and to evaluate the changes of cardiac function at the reperfusion for 30 min and 60 min, to measure the amounts of MB isoenzyme of creatine kinase (CK-MB), lactate dehydrogenase (LDH) and total nitric oxide (NO) oxidation products in the coronary effluent, and to detect myocardial apoptosis on tissue samples of left ventricle at the end of reperfusion by TUNEL staining. RESULTS: Pretreated with LTA significantly improved the recovery of cardiac function with a significant increase in coronary flow (CF), left ventricular developed pressure (LVDP), maximal rate of left ventricular developed pressure (+dp/dt_ max), and minimal rate of left ventricular decline pressure (-dp/dt_ max) at 30 min and 60 min of reperfusion (all P
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Aim To investigate the protective effects of MLT(melatonin) on acute ischemia-reperfusion induced myocardium damage in rats in vivo. Methods 36 anesthetized rats were separated randomly into 3 groups: ① Control group (n=12), without LAD (left anterior descending coronary artery) ligation and MLT; ② I/R(ischemia reperfusion) group(n=12), LAD was ligated for 10 min and reperfused for 15 min without MLT; ③ I/R+MLT group(n=12): MLT(10 mg?kg~(-1)) was in jected via peritonium 10 minutes before LAD ligation and reperfusion. ECG and haemodynamics were continuously monitored and recorded throughout the whole process, MDA(malondialdehyde, lipid peroxidation product, an index of myocardium damage) and SOD( superoxide dismutase ) activity were tested in the injuried myocardium. The hearts tissue of each group was also examinated by electron microscopy.Result The levels of MDA were significantly higher while the SOD activities were lower in I/R group compared with I/R+MLT and control group(P0.05). The haemodynamics indices of contractile and diastolic functions were also better in I/R+MLT group than inI/R group(P