Effect of intravenous injecting plasmid encoding interleukin-19-IgG on experimental autoimmune myocarditis in rats

AIM: To evaluate the effect of intravenous injecting plasmid encoding interleukin-19-IgG on experimental autoimmune myocarditis (EAM) in rats.METHODS: Cardiac myosin was emulsified with equal volume of complete Freund's adjuvant. The animal model of EAM was established by injecting with the preparation in both footpads of the Lewis rats. The rats were intravenously injected with the plasmid encoding IL-19-IgG on day 6. Echocardiography was performed before the rats were sacrificed on day 17. The effect of IL-19-IgG plasmid injection was evaluated by measuring the heart weight/body weight, myocarditis area, relative expression levels of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) in the hearts. The mRNA expression levels of related cytokines including IL-18, IL-1β, IL-12p35 and IFN-γ were detected.RESULTS: The rats in model group showed significant myocardial damage and a decrease in the left ventricular functions. The rats in the treatment group injected with IL-19-IgG plasmid showed an improvement of the cardiac functions. The ratio of heart weight/body weight, the area of myocarditis and the mRNA levels of ANP and BNP were significantly lower in IL-19-IgG treatment group than those in model group. The mRNA levels of IL-18, IL-1β, IL-12p35 and IFN-γ were also significantly decreased in IL-19-IgG treatment group.CONCLUSION: Intravenous injection of plasmid encoding IL-19-IgG effectively prevents the development of the left ventricular remodeling and myocardial damage in EAM rats.     

Effects of cardiac contractility modulation applied to different locations of heart on cardiac functions in rabbits with heart failure

AIM: To investigate the effects of cardiac contractility modulation (CCM) applied to different locations of the heart on cardiac functions and cardiac dys-synchrony in the rabbits with chronic heart failure, and to explore the best pattern of CCM.METHODS: Forty rabbits were divided into 4 groups according to the location of receiving CCM: heart failure (HF) group, left ventricular anterior wall (LVAW-CCM) group, left ventricular posterior lateral wall (LVPLW-CCM) group and right ventricular apex (RVA-CCM) group. The model of chronic heart failure was made by ligating ascending aortic root of the rabbits. After 12 weeks, the electrical stimulations during the absolute refractory period were delivered in different locations of the heart, lasting 6 h everyday for 7 days. The changes of cardiac functions and cardiac dys-synchrony were observed by cardiac ultrasonic cardiogram before and after CCM stimulation. The plasma level of brain natriuretic peptide (BNP) was detected by ABC-ELISA method. Pulsed-wave Doppler was used to acquire aortic pre-ejection interval (APEI) and pulmonary pre-ejection internal (PPEI), and inter-ventricular mechanical delay (IVMD) was calculated to evaluate the cardiac dys-synchrony.RESULTS: Compared with HF group, left ventricular end-systolic dimension (LVESD) and left ventricular end-diastolic dimension (LVEDD) in LVAW-CCM group, LVPLW-CCM group and RVA-CCM group were significantly decreased (P<0.05), while left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) were significantly increased (P<0.05), especially in LVAW-CCM group. Interventricular septal thickness (IVS) and left ventricular posterior wall thickness (LVPW) were similar among groups. No significant difference of plasma BNP level before CCM delivery among the 4 groups was observed. However, the plasma BNP level in control group was the highest, followed by LVPLW-CCM group and RVA-CCM group, and LVAW-CCM group was the lowest after CCM delivery. No change of IVMD was observed among groups before and after CCM delivery.CONCLUSION: The effect of CCM applied to different locations of the heart on cardiac functions is different.The optimal site of CCM delivery is left ventricular anterior wall. No influence of interventricular dys-synchrony was observed during application of CCM.     

Stress induced expression of the angiotensinogen gene in rat anterior pituitary

AIM:To observe the effects of sodium restricted or supplemented on atrial natriuretic polypeptide (ANP) and cardiac function of rats with congestive heart failure (CHF).METHODS:CHF rats were divided into three groups with sham operation rats group as control. Radioimmunassay was used to determine the ANP contents of plasma and myocardium, at the same time cardiac function was measured. RESULTS:In sodium restricted group, the plasma sodium and atrial ANP and left ventricular systolic pressure and artery pressure were obviously lower than those in CHF group, while the plasma and ventricular ANP and the right atrial pressure were remarkably higher; In sodium supplemented group, the plasma sodium and arterial pressure had no obvious change compared with the control, the plasma and myocardium ANP and the right atrial pressure had no difference as compared with CHF group, while the left ventricular end diastolic pressure was remarkably lower and the left ventricular systolic pressure were obviously higher. CONCLUSION:Keeping the balance of plasma sodium by an appropriate supplement of sodium intake after CHF might be beneficial to the ANP biological effects and the cardiac function.     

Effects of soluble transforming growth factor-β type Ⅱ receptor on cardiac functions after myocardial infarction in rats

AIM: To observe the effects of soluble transforming growth factor-β type Ⅱ receptor (sTGFβRⅡ) on cardiac functions after myocardial infarction (MI) in rats. METHODS: MI was induced in Sprague-Dawley (SD) rats by ligating the left anterior descending coronary artery. The rats surviving to the third day after MI were included in the study and randomly divided into MI group, pAd-sTGFβRⅡ group (transfected with recombinant adenovirus vector expressing the extracellular domain gene of TGF-βRⅡ), vector group and sham group. Four weeks later, the heart rate (HR), left ventricular end-diastolic dimension (LVEDD), left ventricular end-systolic dimension (LVESD) and ejection fraction (EF) were evaluated by echocardiograms. The expression of sTGFβRⅡ in myocardial tissues was observed under fluorescence microscope by frozen sectioning, and the expression of typeⅠ and Ⅲ collagens was observed by Sirius red-saturated picric acid staining. The expression of matrix metalloproteinase 9 (MMP-9) at mRNA and protein levels was determined by RT-PCR and immunohistochemical method. The activity of MMP-9 was assayed by gelatin zymography. RESULTS: Compared with sham group, HR, LVEDD, LVESD, typeⅠ and Ⅲ collagen, mRNA and protein of MMP-9, and the activity of MMP-9 increased significantly (P<0.01), and EF decreased (P<0.01) in MI group and vector group. Compared with MI group, EF was increased (P<0.01), but HR, LVEDD, LVESD, typeⅠ and Ⅲ collagen, mRNA and protein expression of MMP-9 and the activity of MMP-9 decreased significantly (P<0.01) in pAd-sTGFβRⅡ group, and all the parameters above were still higher than those in sham group. CONCLUSION: sTGFβRⅡ intervention improves the cardiac functions after MI by inhibiting TGF-β-mediated MMP-9 expression.     

Changes and clinical implications of plasma ANP,BNP and CNP levels in type 2 diabetic patients with vascular complications

AIM:To examine the changes and clinical implications of the plasma atrial natriuretic peptide (ANP), brain natriuretic peptide(BNP) and C-type natriuretic peptide(CNP) levels in type 2 diabetic patients with vascular complications. METHODS:9 subjects without diabetes, 34 diabetic patients without vascular complications and 23 diabetic patients with vascular complications were enrolled in the study and categorized into three groups. Plasma proANP, BNP fragment and N-terminal pro-CNP (NT-proCNP) were measured by enzyme linked immunosorbent assay (ELISA). The changes and associations of the plasma natriuretic peptide levels among three groups were analyzed. RESULTS:Compared with those in the controls and diabetics without vascular complications, the plasma proANP and BNP fragment levels in diabetic patients with vascular complications increased significantly (P<0.01). However, the plasma NT-proCNP level in this group decreased significantly (P<0.01). Nevertheless, no significant differences in the plasma proANP, BNP fragment and NT-proCNP levels among three subgroups (diabetics patients with macrovascular and/or microvascular complications) were observed (P>0.05). The plasma ANP level of diabetic patients with vascular complications was corelated significantly with the BNP levels (r=0.309, P<0.05). Furthermore, the ANP and BNP levels were correlated significantly with the CNP level (r=-0.374, P<0.05; r=-0.653, P<0.01). CONCLUSION:Measurement of the plasma ANP, BNP and CNP levels together may be a simple, cost-effective and reliable way to screen for diabetic patients with vascular complications.     

Role of ubiquitin E3 ligase TRIM10 in regulating cardiomyocyte hypertrophy

AIM: To explore the role of ubiquitin E3 ligase tripartite motif 10 (TRIM10) in the development of cardiomyocyte hypertrophy. METHODS: Primary cultured neonatal rat cardiomyocytes (NRCMs) were infected with siRNA-TRIM10, siRNA-control, Ad-TRIM10 or Ad-GFP for 24 h respectively, and then stimulated with phenylephrine (PE) for additional 24 h. The protein levels of TRIM10, AKT and ERK1/2 were determined by Western blot. The size of the NRCMs was measured by immunofluorescence staining. The mRNA expression of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) was detected by RT-qPCR. RESULTS: Compared with the control, PE treatment significantly increased the protein expression of TRIM10. Moreover, transfection of NRCMs with siRNA-TRIM10 markedly inhibited cardiomyocyte size, the mRNA expression of ANP and BNP, and the phosphorylation levels of AKT and ERK as compared with siRNA-control after PE treatment. In contrast, overexpression of TRIM10 significantly enhanced PE-induced hypertrophic effect on NRCMs above. CONCLUSION: TRIM10 regulates cardiomyocyte hypertrophy partially through AKT and ERK signaling pathways.     

Effects of Qili Qiangxin capsule on serum concentration of adiponectin and heart function in patients with coronary heart disease combined with congestive heart failure

AIM：To investigate the effects of Qili Qiangxin capsule on serum adiponectin (APN), serum N-terminal pro-brain natriuretic peptide (NT-proBNP) and heart function in the patients of coronary heart disease combined with congestive heart failure. METHODS：One hundred and twenty patients were randomly divided into treatment group and control group, and both groups were given anti-failure routine therapy. The patients in treatment group were treated with Qili Qiangxin capsule and the patients in control group were treated with placebo. The patients in the 2 groups were given a certain dose of the drugs for 6 months. The New York Heart Association (NYHA) heart function classification, left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD),left ventricular ejection fraction (LVEF), and 6-min walking test (6-MWT) were observed before and after treatment. The levels of APN, NT-proBNP were measured by ELISA before and after treatment. RESULTS：With the increase in the class of NYHA heart function, the serum concentrations of APN and NT-proBNP in the heart failure cases increased significantly. After 6-month treatment, the effective rate in experimental group was 91.7% and that in control group was 75.0%. A significant difference was found between the 2 groups (P<0.01). After treatment, LVEDD and LVESD in both groups were decreased significantly, and LVEF in both groups was increased significantly. The serum concentrations of APN and NT-proBNP decreased significantly (P<0.05). 6-MWT result was improved significantly. Compared with control group, more obvious effect was observed in experimental group (P<0.05). CONCLUSION：Treatment with Qili Qiangxin capsule reduces the levels of APN and NT-proBNP in the patients with coronary heart disease combined with congestive heart failure.     

Effect of BNP- mediated cAMP-PKA signaling pathway on bFGF expression in rats with spleen-qi deficiency syndrome

AIM: To explore the changes and the mechanism of heart functions in the rats with spleen-qi deficiency syndrome. METHODS: The rats were randomly divided into blank control group and spleen-qi deficiency model group. The changes of cardiac functions in the rats were determined by ultrasonic imaging with a high-resolution in vivo imaging system. HE staining was used to observe the pathological changes. The protein expression of brain natriuretic peptide (BNP) in the myocardium was assessed by Western blotting. The contents of BNP and cAMP in the serum and myocardium were measured by ELISA. The mRNA expression of basic fibroblast growth factor (bFGF) and protein kinase A (PKA) was detected by real-time PCR. RESULTS: Compared with blank control group, the myocardial cells in the model group had different degrees of necrosis and degeneration. Stroke volume and ejection fraction were decreased. The contents of cAMP and BNP in the serum and myocardium were increased in model group. The protein expression of BNP and the mRNA expression of bFGF and PKA were also increased.CONCLUSION: Spleen-qi deficiency syndrome causes heart function decline in rats. The expression of BNP, cAMP, PKA and bFGF is all increased.     

Level of copeptin for early prediction of cardiorenal syndrome in rats

AIM: To study the value of copeptin (CPP) level for the prediction of cardiorenal syndrome (CRS) in the rats with subtotal nephrectomy (SNX) combined with myocardial infarction (MI).METHODS: Male SD rats (n=60) were divided into blank control group (Con group), renal failure group (SNX group), heart failure group (MI group) and heart failure+renal failure group (CRS group). The concentrations of CPP in the serum and urine, hemodynamic indexes, blood pressure and renal function indexes were measured 1~5 weeks after modeling. The predictive value of CPP for CRS in the rats was evaluated by the receiver operating characteristic (ROC) curve.RESULTS: Compared with Con group, left ventricular systolic pressure (LVSP) at 9 d in CRS group was significantly decreased (P<0.05), left ventricular end-diastolic pressure (LVEDP) at 9 d in CRS group was significantly increased (P<0.05), and the difference of blood pressure at each time point was not statistically significant. The levels of blood urea nitrogen (BUN) and urinary creatinine (UCr) in CRS group were significantly increased at 1 and 3 weeks (P<0.05). Compared with Con group, serum CPP level was significantly increased at 1, 3 and 5 weeks (P<0.05), and urine CPP level was significantly increased at 3 weeks in CRS group. Serum brain natriuretic peptide (BNP) level was significantly increased at 1 and 3 weeks, while urine BNP level was significantly increased at 5 weeks after modeling in CRS group (P<0.05). No correlation between serum or urine CPP and BNP or BUN levels at 1 week in CRS group was observed. The results of ROC curve analysis indicated that the area under the curve (AUC) of serum CPP was 0.908 (95% CI:0.789~1.028), and the cut-off value was 56.59 ng/L (sensitivity 0.875, specificity 0.800).CONCLUSION: The combination of SNX and MI establishes a CRS rat model with both heart and kidney injury, and serum CPP can be used as a sensitive and specific biomarker for early prediction of CRS.     

Inhibition of Rac1 protects cardiac functions in STZ-induced diabetic cardiomyopathy through decreasing pho-p38 MAPK

AIM: To investigate the effects of Rac1 inhibition on the size of cardiomyocytes and left ventricular functions in diabetic cardiomyopathy. METHODS: Type 1 diabetes was induced in 8-week old C57 mice by streptozotocin (STZ, ip injection). Diabetic mice were treated with NSC23766, a specific inhibitor of Rac1 (STZ+NSC group, n=15) or without treatment (STZ group, n=15). Nondiabetic mice were used to serve as empty control (Con group, n=10) or NSC23766 control (NSC group, n=10). The survival rate, LVHW/BW and left ventricular functions were detected at the end of 8 weeks after induction of diabetes. The expression of ANP, BNP, β-MHC and pho-p38 MAPK in the cardiac tissues were analyzed by real-time RT-PCR and Western blotting, respectively. Hematoxylin and Eosin staining (HE) was used to measure the cell size in the cardiac tissues. RESULTS: The functions of left ventricle were significantly impaired in the diabetic animals with decreased survival rate and increased LVHW/BW, which was accompanied by significant increases in ANP, BNP and β-MHC, and elevated pho-p38 MAPK expression in diabetic hearts. The increased survival rate, improved left ventricular functions and decreased LVHW/BW were observed in the diabetic animals treated with NSC. The mRNA expression of ANP, BNP, β-MHC and pho-p38 MAPK was significantly attenuated in the diabetic hearts by NSC treatment. The size of the cardiomyocytes, which increased in diabetic hearts, was decreased in the NSC-treated diabetic cardiac tissue. CONCLUSION: Rac1 inhibition protects left ventricular functions and attenuates hypertrophy, which is associated with the decrease in pho-p38 MAPK expression in diabetic heart. These data suggest that inhibition of Rac1 might be beneficial to diabetic cardiomyopathy.     

Effect of erythropoietin on expression of myocardial NADPH oxidase in pressure overload rats

AIM:To explore the effect of erythropoietin （EPO） on the expression of myocardial NADPH oxidase （Nox） in the pressure overload rats. METHODS:Male SD rats (n=36) were used to establish a pressure overload myocardial hypertrophy model by abdominal aorta ligation. The animals were divided into model group, control group (sham, without narrowing abdominal aorta, the rest of the operation was the same as the model) and recombinant human erythropoietin (rhEPO) treatment group (intraperitoneal injection of rhEPO postoperatively, 4 000 U/kg, twice a week). After 8 weeks, the cardiac ultrasound imaging and hemodynamic evaluation were conducted to determine the cardiac functions. Masson staining was used to observe the degree of myocardial fibrosis. The expression of Nox2 and Nox4 at mRNA and protein levels was detected by real-time quantitative PCR and Western blotting. The protein levels of myocardial inflammatory factors CD45, F4/80 and TGF-β were determined by Western blotting. RESULTS:Compared with model group, the left ventricular ejection fraction (LVEF), left ventricular fractional shortening (LVFS), left ventricular end-systolic pressure (LVESP) and left ventricular pressure maximum rising and falling rates (±dp/dtmax) increased significantly in EPO treatment group (P<0.01). At the same time, left ventricular end-systolic diameter (LVESD), left ventricular end-diastolic diameter (LVEDD) and left ventricular end-diastolic pressure (LVEDP) were decreased in EPO treatment group (P<0.01). EPO reduced the degree of myocardial fibrosis caused by pressure overload (P<0.01) and decreased the expression of Nox2 and Nox4 at mRNA and protein levels in the myocardium (P<0.05 or P<0.01), and reduced the protein expression of myocardial inflammatory factors CD45, F4/80 and TGF-β. CONCLUSION: EPO inhibits rat myocar-dial fibrosis induced by pressure overload, improves heart functions by decreasing NADPH oxidase activity and inhibiting myocardial oxidative stress levels and myocardial inflammatory reaction.     

Effects of sodium hydrosulfide on cardiac function and activity of renin-angiotensin-aldosterone system in rats with chronic heart failure

AIM: To investigate the effect of sodium hydrosulfide (NaHS) on cardiac function and activity of renin-angiotensin (Ang)-aldosterone (ALD) system (RAAS) in the rats with chronic heart failure (CHF).METHODS: The CHF rat model was established by abdominal aortic coarctation. SD rats were randomly divided into sham operation group, model group, low dose of NaHS group and high dose of NaHS group (n=6). The left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD) and left ventricular ejection fraction (LVEF) were measured before and after treatment by echocardiography in each group. The levels of renin, AngⅡ and ALD in the plasma were measured by ELISA. The expression of angiotensin-converting enzyme (ACE) and angiotensin Ⅱ type 1 receptor (AT1R) at mRNA and protein levels in the myocardium tissues was determined by qPCR and Western blot, respectively.RESULTS: After treatment with NaHS, compared with model group and before treatment, LVEDD and LVESD in low dose of NaHS group and high dose of NaHS group were decreased significantly, while LVEF was increased significantly (P<0.05). Compared with low dose of NaHS group, LVEDD and LVESD were decreased, while LVEF was increased in high dose of NaHS group (P<0.05). Compared with sham operation group, the levels of renin, AngⅡ and ALD in the plasma of model group were significantly increased (P<0.05), and the expression of ACE and AT1R at mRNA and protein levels in the myocardium tissues of model group were significantly increased (P<0.05). Compared with model group, the plasma levels of renin, AngⅡ and ALD in low dose of NaHS group and high dose of NaHS group were significantly decreased (P<0.05), and the myocardial expression of ACE and AT1R at mRNA and protein levels was significantly down-regulated (P<0.05). The plasma levels of renin, AngⅡ and ALD, and the myocardial expression of ACE and AT1R at mRNA and protein levels in high dose of NaHS group were significantly lower than those in low dose of NaHS group (P<0.05).CONCLUSION: NaHS inhibits the activation of RAAS, thus improving the cardiac function of CHF rats, and the effect of high-dose NaHS is better than that of low-dose NaHS.     

设施番茄长期连作土壤微生物群落结构及多样性分析

 利用PCR-DGGE 技术,研究了裸地及不同连作年限的设施番茄栽培土壤中细菌和真菌的群 落结构及多样性的变化情况。结果表明：设施条件下种植番茄明显改变了土壤土著细菌的群落结构,但 连作年限对土壤细菌多样性影响较小,细菌群落结构变化不大;土著真菌的群落结构稳定性优于土著细 菌,但土壤真菌的优势种群在不同连作年限的土样中变化较大,连作显著降低了某些真菌的数量,同时 显著增加了另一些真菌的数量,其中,连作20 年番茄的土壤真菌新出现的优势种群最多,且与非优势种 群的真菌数量差异较大,这种番茄连作后改变土壤真菌种群平衡的现象可能是导致番茄产生连作障碍的 重要原因之一。通过电泳条带的回收、测序,可知所取土样中的细菌优势种群属于Clostridium butyricum、 Uncultured bacterium、Bacillus 和Arthrobacter,真菌优势种群属于Saccobolus dilutellus、Uncultured fungus、 Lasiobolus ciliatus、Spooneromyces laeticolor 和Lasiobolidium orbiculoides。     

Long-term insulin treatment improves postischemic cardiac structure and function via increasing serum BNP levels

AIM：To investigate the influence of long-term insulin treatment on postischemic cardiac structural and functional changes, and to further explore the underlying mechanisms. METHODS：Adult male SD rats were randomly divided into 4 groups (8~10 rats per group): sham group, myocardial infarction (MI) + saline (1 mL·kg-1·d-1, hypodermic injection for 4 weeks) group, MI + insulin (2 U·kg-1·d-1, hypodermic injection for 4 weeks) group and MI + insulin (2 U·kg-1·d-1, hypodermic injection for 4 weeks) + wortmannin ［a phosphatidylinositol 3-kinase (PI3K) inhibitor; 15 μg·kg-1·d-1, intraperitoneal injection 15 min before each insulin treatment］ group. The rats in the latter 3 groups were subject to ligation of the left anterior descending coronary artery, while those in sham group underwent the same surgical procedures without tying the sutures. The cardiac structural and functional changes were observed by echocardiogram, heart catheterization and microscopy with HE and Masson trichrome staining. Blood glucose was determined by Roche blood glucose meter, and the serum levels of insulin and brain natriuretic peptide (BNP) were detected by ELISA. The protein expression and phosphorylation of PI3K, Akt, glycogen synthase kinase 3β (GSK3β) and p38 mitogen-activated protein kinase (p38 MAPK) in myocardial tissues were detected by Western blotting. The mRNA expression of BNP, β-myosin heavy chain (β-MHC) and atrial natriuretic peptide (ANP) in myocardial tissues was determined by real-time fluorescence quantitative PCR. RESULTS：At the end of the 4th week, MI rats receiving long-term insulin treatment showed decreased ratio of heart length/heart weight, smaller systolic left ventricle cavity, thicker systolic interventricular septum, and increased cardiac ejection fraction, left ventricular development pressure and instantaneous first derivate of left ventricle pressure (P<0.05 vs MI + saline group). Moreover, insulin treatment significantly increased the phosphorylation of PI3K and Akt and the serum level of BNP, and inhibited the phosphorylation of p38 MAPK (P<0.05 vs MI + saline group), but did not change the mRNA expression of BNP in myocardial tissues. The effects of insulin on BNP were not blocked by wortmannin (P>0.05 vs MI + insulin group). CONCLUSION：Insulin improves postischemic cardiac structure and function by increasing serum BNP levels possibly independent of PI3K-Akt signaling pathway.     

Effect of gene delivery plasmid encoding interleukin-1 receptor Ⅱ for treating rat autoimmune myocarditis

AIM: To evaluate the effect of gene delivery plasmid encoding interleukin-1 receptor Ⅱ (IL-1RⅡ) for treating rat experimental autoimmune myocarditis (EAM). METHODS: Cardiac myosin was emulsified with equal volume of complete Freund's adjuvant, and EAM model was produced by injection with the preparation in both footpads of Lewis rats. The rats were immunized on day 0 and were injected with plasmid encoding IL-1RⅡ by hydrodynamics-based gene delivery on day 6. The expression of IL-1RⅡ on day 7, day 12 and day 17 was determined by Western blotting. Echocardiography was performed on day 16 and the rats were sacrificed on day 17. The effect of IL-1RⅡ gene therapy was evaluated by the ratio of heart weight/body weight, histopathological scores, relative expression of brain natriuretic peptide (BNP) in hearts and the echocardiographic parameters. The expression levels of IL-1-related cytokines, including IL-1β, prostaglandin E₂ synthase (PGES) and monocyte chemotactic protein-1 (MCP-1) were also detected. RESULTS: The expression of IL-1RⅡincreased on day 7 after hydrodynamics-based gene delivery and maintained at high level until day 17. The rats in control group showed significant myocardial damage and a decrease in the left ventricular functions. The rats in the treatment group injected with IL-1RⅡ plasmid showed an improvement of the cardiac functions. The ratio of heart weight/body weight, the histopathological scores and the level of BNP were significantly lower in treatment group than those in control group. The expression of IL-1β, PGES and MCP-1 at mRNA and protein levels was also significantly inhibited in IL-1RⅡ treatment group. CONCLUSION: Hydrodynamics-based gene delivery plasmid encoding IL-1RⅡ effectively prevents the progression of the left ventricular remodeling and myocardial damage in rat EAM.     

Effects of ERK1/2 on pressure overload-induced cardiomyopathy and heart failure in mice

AIM: To explore the changes in extracellular regulated protein kinase (ERK1/2) in the hypertrophic myocardium induced by pressure overload at the different time courses and to determine the molecular mechanism in the myocardium from hypertrophy to heart failure. METHODS: C57/BL mice, aged 12 week old, were subjected to sham-operation (SH) or transversing aortic constriction (TAC) to establish left ventricular hypertrophy. Echocardiographic assessments, hemodynamic determination, organ weight measurement, morphological and histological examination were performed at 1, 4, 8, 12 and 16 weeks after surgery. Meanwhile mRNA levels of atrial natriuretic peptide (ANP), α-myosin heavy chain (α-MHC), bcl-2 and bax were measured by RT-PCR, and ERK1/2 levels were detected by Western blotting. The animals in SH group were performed the same tests then sacrificed at 16 weeks. RESULTS: (1) Compared to SH group, LVESd, LVEDd, Awsth, Awdth, Pwsth and Pwdth progressively increased after TAC. Meanwhile, ejection fraction (EF%) significantly decreased at 16th week (P<0.05). LVSP, dp/dtmax and dp/dtmin in TAC group were progressively increased after 4 weeks. From 8-12 weeks these parameters maintained stable and then sharply decreased at 16th week (all P<0.05). However, LVEDP was statistically increased at 8th week. These echocardiographic and hemodynamic changes indicated a development of LVH and eventually progressing towards to heart failure. (2) Histologically, cardiac collagen measured by percentage of Sirius red positive stained area and apoptosis index showed progressive increases from 4 to 16 weeks. (3) Compared to SH group, mRNA levels of ANP was time-dependently increased while α-MHC and Bcl-2 were time-dependently decreased. The ratio of Bcl-2 /Bax was decreased. Phosphorylation of ERK1/2 was increased at 4th week, then decreased with age of TAC (all P<0.05). CONCLUSION: Pressure-overload induced by TAC results in a development of LVH from early concentric hypertrophy to late eccentric hypertrophy, and eventually toward cardiac dysfunction or heart failure. Those changes are associated with increase in cell size and cardiac fibrosis. ERK1/2 signaling pathway may involve in the regulation of myocardial cell apoptosis in hypertrophic and failure heart.     

Changes of aryl hydrocarbon receptor in cardiac hypertrophy induced by high glucose in vitro

AIM: To investigate the changes of aryl hydrocarbon receptor (AhR) in the process of cardiomyocyte hypertrophy induced by high glucose, and to explore its potential mechanisms. METHODS: The rat cardiomyocytes (H9c2 cells) were divided into normal glucose group, high glucose group, DMSO group and resveratrol (an AhR antagonist) group. The content and distribution of AhR were observed with immunofluorescence staining. The myocardial cells were stained with rhodamine-labeled phalloidin to visualize cytoskeleton, and the cell surface area were determined after imaging by fluorescence microscopy. The generation of reactive oxygen species (ROS) in the cardiomyocytes was measured using a fluorescent probe DCFH-DA. The mRNA expression of AhR, CYP1A1, atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) were evaluated by real-time quantitative PCR (RT-qPCR). The protein levels of AhR, CYP1A1, ANP and BNP were assessed by Western blot. RESULTS: AhR was constitutively presented in the cytosol under normal-glucose condition and was translocated to the nuclei under high-glucose condition. High glucose induced cardiac hypertrophy, and increased ROS generation. Significant reductions in the cell size and ROS generation were observed after treated with resveratrol. The expression of AhR, CYP1A1, ANP and BNP at mRNA and protein levels in high glucose group was increased as compared with normal glucose group and resveratrol group, and the above-mentioned indexes significantly decreased in resveratrol group as compared with DMSO group. CONCLUSION: High glucose-induced cardiac hypertrophy increases AhR expression, which may be involved in the maintenance of glucose homeostasis in the cardiomyocytes. AhR translocation to the nucleus induced by high glucose results in the increases in CYP1A1 expression and ROS generation, which may be an important mechanism of high glucose-induced cardiomyocyte hypertrophy.     

Effects of Xinkang recipe on myocardial miR-25-3p expression and SERCA2a activity in heart failure rats

AIM: To investigate the effects of Xinkang recipe on myocardial miR-25-3p expression and sarcoplasmic reticulum calcium ATPase 2a (SERCA2a) activity in heart failure rats. METHODS: Male SD rats were randomly divided into normal group, sham group, model group, Xinkang recipe group (Xinkang group), and captopril group. The heart failure rat model was induced by intraperitoneal injection of doxorubicin. Distilled water, Xinkang recipe and captopril were administrated by gastric gavage for 35 d, respectively. The indexes of cardiac function and plasma level of brain natriuretic peptide (BNP) were measured. The SERCA2a activity was determined by the inorganic phosphorus method. The myocardial protein expression of SERCA2a and phospholamban (PLB) was detected by Western blot. The myocardial expression of miR-25-3p was detected by stem-loop RT-qPCR. RESULTS: Cardiac output (CO), left ventricular fractional shortening (LVFS) and left ventricular ejection fraction (LVEF) in Xinkang group and captopril group were significantly higher while the plasma levels of BNP were significantly lower than those in model group (P<0.01). The myocardial expression levels of miR-25-3p in Xinkang group and captopril group were significantly lower while the myocardial protein le-vels of SERCA2a and PLB were significantly higher than those in model group (P<0.01). The SERCA2a/PLB ratio and SERCA2a activity in Xinkang group were significantly higher than those in model group (P<0.05), and no significant change was observed between captopril group and model group. CONCLUSION: Xinkang recipe therapy may improve cardiac function in heart failure rats, which may be related to inhibiting the expression of miR-25-3p, increasing the SERCA2a/PLB ratio and enhancing SERCA2a activity in the myocardium.