Inhibitor of growth protein-2 silencing alleviates angiotensin Ⅱ-induced cardiac remodeling in mice by reducing p53 acetylation / 南方医科大学学报

OBJECTIVE@#To investigate the effect of inhibitor of growth protein-2 (Ing2) silencing on angiotensin Ⅱ (AngⅡ)-induced cardiac remodeling in mice and explore the underlying mechanism.@*METHODS@#An adenoviral vector carrying Ing2 shRNA or empty adenoviral vector was injected into the tail vein of mice, followed 48 h later by infusion of 1000 ng · kg-1 · min-1 Ang Ⅱ or saline using a mini-osmotic pump for 42 consecutive days. Transthoracic echocardiography was used to assess cardiac geometry and function and the level of cardiac hypertrophy in the mice. Masson and WGA staining were used to detect myocardial fibrosis and cross-sectional area of cardiomyocytes, and myocardial cell apoptosis was detected with TUNEL assay. Western blotting was performed to detect myocardial expressions of cleaved caspase 3, ING2, collagen Ⅰ, Ac-p53(Lys382) and p-p53 (Ser15); Ing2 mRNA expression was detected using real-time PCR. Mitochondrial biogenesis, as measured by mitochondrial ROS content, ATP content, citrate synthase activity and calcium storage, was determined using commercial assay kits.@*RESULTS@#The expression levels of Ing2 mRNA and protein were significantly higher in the mice with chronic Ang Ⅱ infusion than in saline-infused mice. Chronic infusion of AngⅡ significantly increased the left ventricular end-systolic diameter (LVESD) and left ventricular end-diastolic diameter (LVEDD) and reduced left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) in the mice. Ing2 silencing obviously alleviated AngⅡ-induced cardiac function decline, as shown by decreased LVEDD and LVESD and increased LVEF and LVFS, improved myocardial mitochondrial damage and myocardial hypertrophy and fibrosis, and inhibited cardiomyocyte apoptosis. Chronic AngⅡ infusion significantly increased myocardial expression levels of Ac-p53(Lys382) and p-p53(Ser15) in the mice, and Ing2 silencing prior to AngⅡ infusion lessened AngⅡ- induced increase of Ac-p53(Lys382) without affecting p53 (ser15) expression.@*CONCLUSION@#Ing2 silencing can inhibit AngⅡ-induced cardiac remodeling and dysfunction in mice by reducing p53 acetylation.

Improvement effects of total flavonoids of Psidium guajava leaves on myocardial hypertrophy in hypertensive model rats / 中国药房

OBJECTIVE To study the imp rovement effects of total flavonoids of Psidium guajava leaves on myocardial hypertrophy in hypertensive model rats. METHODS Ten rats were randomly selected from 60 healthy SD rats as the normal group ； other 50 rats established hypertensive model ，and 44 rats with successful modeling were randomly divided into model group ， anisomycin group [p38 mitogen-activated protein kinase （p38 MAPK）activator，1 mg/kg]，total flavonoids of P. guajava leaves+ anisomycin group （200 mg/kg total flavonoids+ 1 mg/kg anisomycin ）and total flavonoids of P. guajava leaves group （200 mg/kg） by random volume mass ranking method ，with 11 rats in each group. Rats in normal group and model group were given 3％ hydroxymethylcellulose sodium solution ，and other groups were given relevant solution intragastrically ，once a day ，for consecutive 6 weeks. Blood pressure （systolic blood pressure ，diastolic blood pressure ，mean arterial pressure ），cardiac index and left ventricular index were measured. The levels of tumor necrosis factor-α（TNF-α），interleukin-1β（IL-1β）and IL- 6 in myocardial tissue were detected. The pathomorphological changes of myocardial tissue were observed. The expression of p 38 MAPK， phosphorylated p 38 MAPK （p-p38 MAPK），extracellular regulated protein kinase 1/2 （ERK1/2），phosphorylated ERK 1/2 （p-ERK1/2），c-Jun N-terminal kinase （JNK）and phosphorylated JNK （p-JNK）in myocardial tissue were detected. RESULTS Compared with normal group ，the systolic blood pressure ，diastolic blood pressure ，mean arterial pressure ，cardiac index ，left ventricular index as well as the levels of TNF-α，IL-1β and IL-6 and protein expression of p-p 38 MAPK，p-ERK1/2 and p-JNK in myocardial tissue were increased significantly in anisomycin group and model group （P＜0.05）；it was also found that hypertrophy of cardiomyocytes ，disorder of myocardial fibers ，looseness，edema and proliferation of connective tissue between myocardial fibers，increased infiltration of inflammatory cells ，etc. Compared with anisomycin group and model group ，the le vels of above indexes in total flavonoids of P. guajava leaves+ anisomycin group and total flavonoids of P. guajava leaves group were decreased significantly （P＜0.05）； cardiomyocytes were 163.com slightly larger and arranged reasonably ；the degree of myocardial hypertrophy，looseness，edema and proliferation of connective tissue were relieved ，and the improvement effect of total flavonoids of P. guajava leaves group was more significant （P＜0.05）. CONCLUSIONS The total flavonoids of P. guajava leaves can reduce blood pressure and improve myocardial hypertrophy in hypertensive model rats. Its mechanism may be related to the inhibition of p38 MAPK signal pathway activity and the expression of inflammatory factors.

Pathological Process Observation and Non-targeted Metabolomics Analysis of Heart Failure Rat Model Established by Transverse Aortic Constriction / 中国实验方剂学杂志

ObjectiveTo study the pathological process and changes of metabolites in myocardial tissue of heart failure induced by transverse aortic constriction （TAC） in rats. MethodRats were treated with TAC operation and divided into TAC-30 d group and TAC-60 d group， and sham operation group at the same period was set up as control. Echocardiography and pathological staining of myocardial tissue were performed on rats in each group. Enzyme-linked immunosorbent assay was used to determine the expression of amino-terminal pro-brain natriuretic peptide （NT-proBNP） and adenosine triphosphate （ATP） in serum. Liquid chromatography-mass spectrometry was used to observe the changes of metabolites and related pathways in myocardial tissue， the mobile phase consisted of 25 mmol·L-1 ammonium acetate and 25 mmol·L-1 ammonia hydroxide in water （A） and acetonitrile （B） for gradient elution （0-0.5 min， 95%B； 0.5-7 min， 95%-65%B； 7-8 min， 65%-40%B； 8-9 min， 40%B； 9-9.1 min， 40%-95%B； 9.1-12 min， 95%B）， electrospray ionization was used under positive and negative ion detection modes， acquisition range was m/z 70-1 050. ResultCompared with the sham-30 d group， the left ventricular internal diameter at end-systole （LVIDs） in TAC-30 d group was significantly decreased （P<0.01）， and left ventricular ejection fraction （LVEF）， fraction shortening （FS）， left ventricular end-diastolic posterior wall thickness （LVPWd）， left vebtricular end-systolic posterior wall thickness （LVPWs） were significantly increased （P<0.01）， there were cardiomyocyte arrangement disorder， edema， collagen fibre hyperplasia， the content of NT-probNP was significantly increased， while the content of ATP was significantly decreased （P<0.01）， and 15 metabolites with abnormal expression were involved in pyrimidine metabolic pathway， pantothenic acid and coenzyme A biosynthesis pathway. Compared with the sham-60 d group， LVEF and FS in the TAC-60 d group were significantly decreased （P<0.01）， and left ventricular internal diameter at end-diastole （LVIDd）， LVIDs and LVPWd were increased （P<0.05， P<0.01）， the edema of myocardial cells increased obviously， myocardium fibers degenerated， coagulation necrosis appeared， and a large amount of collagen fibers were deposited， the expression of NT-proBNP increased and the expression of ATP decreased （P<0.01）， there were 21 metabolites with abnormal expression， involving pyrimidine metabolic pathway， and starch and sucrose metabolic pathway. ConclusionAt 30 d after TAC， there are myocardial hypertrophy， lipid metabolism disorder， pyrimidine metabolism disorder and energy imbalance. At 60 d after TAC， there are heart failure， aggravation of lipid metabolism disorder， excessive activation of glucose metabolism， and continuous disorder of pyrimidine metabolism.

The effects of moderate intensity exercise on left ventricular remodeling in spontaneously hypertensive rats / 中华物理医学与康复杂志

Objective:To observe any effect of moderate-intensity exercise on left ventricular remodeling (such as cardiomyocyte hypertrophy, apoptosis and proliferation) in spontaneously-hypertensive rats (SHRs) and explore the possible mechanisms.Methods:Thirty 4-month-old female SHRs were randomly divided into a sedentary group ( n=15) and an exercise group ( n=15). Fifteen Wistar Kyoto rats served as the control group. The exercise group underwent daily 60-min moderate-intensity treadmill exercise 5 days per week for 12 weeks, while the sedentary and control groups were raised quietly in cages for the same period. After the 12-week intervention, the caudal artery blood pressure was measured using a non-invasive blood pressure monitor. The rats were then sacrificed and their hearts were sampled for morphometric measurement. Cardiomyocytes were isolated and underwent DAPI staining to measure their length, width and area. Apoptosis cardiomyocytes was detected by using terminal-deoxynucleoitidyl transferase mediated nick end labeling and their proliferation was assessed using immunofluorescent staining. The number of cardiac progenitor cells was detected by flow cytometry, while the expression of the cardiac calcineurin Aβ subunit (CNAβ) and phosphorylated Akt (p-Akt) protein were measured using western blotting. Results:Compared with the control group, a significant increase was observed in the heart weight, heart mass index (HMI), systolic blood pressure, diastolic blood pressure, myocardial thickness of the left ventricular wall (anterior wall, posterior wall and septal wall), cardiomyocyte morphology (length, width and area), cardiomyocyte apoptosis rate, proliferation rate, number of cardiac progenitor cells and protein expression of CNAβ in the sedentary group. Compared with the sedentary group, the average heart weight, HMI, myocardial thickness of the left ventricular wall (anterior wall, posterior wall and septal wall), cardiomyocyte morphology (length, width and area), cardiomyocyte proliferation rate, number of cardiac progenitor cells and p-Akt protein expression had increased significantly in the exercise group. The average systolic blood pressure, diastolic blood pressure, apoptosis rate and CNAβ protein expression had decreased significantly.Conclusions:Moderate-intensity exercise can induce physiological cardiac hypertrophy in SHRs, relieve apoptosis, increase the number of cardiac progenitor cells and promote cell proliferation, thereby inhibiting cardiac remodeling.

Magnolol attenuates right ventricular hypertrophy and fibrosis in hypoxia-induced pulmonary arterial hypertensive rats through inhibition of the JAK2/STAT3 signaling pathway / 中国药理学与毒理学杂志

OBJECTIVE Right ventricular (RV) remodeling is one of the essential pathological features in pulmonary arterial hypertension (PAH). RV hypertrophy or fibrosis are the leading causes of RV remodeling. Magnolol is a com?pound isolated from Magnolia officinalis. It possesses multiple pharmacological activities, such as anti-oxidation and anti-inflammation. This study aims to evaluate the effects and underlying mechanisms of magnolol on RV remodeling in hypoxia-induced PAH. METHODS ① Male SD rats (220 g) were randomly divided into 5 groups (n=10): the normoxia group, the hypoxia group, the hypoxia plus Magnolol (10 and 20 mg·kg-1·d-1) group, and the vehicle group. Rats in the normoxia group were kept in a normoxia environment for 4 weeks, while rats in the hypoxia group were kept in a hypoxic chamber (10％ O2). The rats in the hypoxia plus magnolol groups were administered with magnolol at 10 or 20 mg·kg-1 (ip) once a day for 4 weeks. At the end of 4 weeks, the heart function was assessed by Doppler echocardiography, and then the rats were anesthetized with sodium pentobarbital (30 mg·kg-1, ip). The RVSP was measured by the right heart catheterization method. The heart tissues were collected and dissected to calculate the index of RV remodeling (RV/LV+IVS, RV/tibial length, or RV/body weight). Part of the RV samples was fixed with 4％paraformaldehyde for morphological analysis, while other samples were frozen at-80℃for molecular studies (measurements of ANP, BNP,α-SMA, and col?lagen Ⅰ/Ⅲ mRNA expression as well as p-JAK2/JAK2 and p-STAT3/STAT3 protein levels). ② To evaluate the effect of magnolol on hypoxia-induced myocardial hypertrophy and fibrosis, H9c2 or cardiac fibroblasts were divided into 7 groups: the control group, cells were cultured under normal conditions; the hypoxia group, cells were cultured under hypoxic condition (3％ O2);the hypoxia plus magnolol 10 mg·kg-1 group, magnolol10μmol·L-1 was added to the culture medium before the hypoxia treatment;the hypoxia plus magnolol 30 mg·kg-1 group, magnolol 20μmol·L-1 was added to the culture medium before the hypoxia treatment;the hypoxia plus TG-101348 group, TG-101348 (a specific inhibitor of JAK2) 1μmol·L-1 was added to the culture medium before the hypoxia treatment;the hypoxia plus JSI-124 group, JSI-124 (a specific inhibitor of JAK2) 1μmol·L-1 was added to the culture medium before the hypoxia treatment;and the hypoxia plus vehicle group, an equal volume of vehicle (DMSO) was added to the culture medium before the hypoxia treatment. At the end of the experiments, the cells were collected for morphological and molecular analysis. RESULTS In vivo, male Sprang-Daley rats were exposed to 10％ O2 for 4 weeks to establish an RV remodeling model, which showed hypertrophic and fibrotic features (increases of RV remodeling index, cellular size, hypertrophic and fibrotic marker expression), accompanied by an elevation in phosphorylation levels of JAK2 and STAT3;these changes were attenuated by treating rats with magnolol. In vitro, the cultured H9c2 cells or cardiac fibroblasts were exposed to 3％ O2 for 48 h to induce hypertrophy or fibrosis, which showed hypertrophic (increases in cellular size as well as the expression of ANP and BNP) or fibrotic features (increases in the expression of collagenⅠ, collagenⅢandα-SMA). Administration of mag?nolol and TG-101348 or JSI-124 (JAK2 selective inhibitors) could prevent the process of myocardial hypertrophy and fibrosis, accompanied by the decrease in the phosphorylation level of JAK2 and STAT3. CONCLUSION Magnolol can attenuate RV hypertrophy and fibrosis in hypoxia-induced PAH rats through a mechanism involving inhibition of the JAK2/STAT3 signaling pathway.

Chikusetsu saponin Ⅳa ameliorates myocardial hypertrophy of rats through regulating expression of miR199a-5p/Atg5 / 中国中药杂志

The present study investigated the effects of chikusetsu saponin Ⅳa(CHS Ⅳa) on isoproterenol(ISO)-induced myocardial hypertrophy in rats and explored the underlying molecular mechanism. ISO was applied to establish a rat model of myocardial hypertrophy, and CHS Ⅳa(5 and 15 mg·kg~(-1)·d~(-1)) was used for intervention. The tail artery blood pressure was measured. Cardiac ultrasound examination was performed. The ratio of heart weight to body weight(HW/BW) was calculated. Morphological changes in the myocardial tissue were observed by HE staining. Collagen deposition in the myocardial tissue was observed by Masson staining. The mRNA expression of myocardial hypertrophy indicators(ANP and BNP), autophagy-related genes(Atg5, P62 and beclin1), and miR199 a-5 p was detected by qRT-PCR. Atg5 protein expression was detected by Western blot. The results showed that the model group exhibited increased tail artery blood pressure and HW/BW ratio, thickened left ventricular myocardium, enlarged myocardial cells, disordered myocardial fibers with widened interstitium, and a large amount of collagen aggregating around the extracellular matrix and blood vessels. ANP and BNP were largely expressed. Moreover, P62 expression was up-regulated, while beclin1 expression was down-regulated. After intervention by CHS Ⅳa at different doses, myocardial hypertrophy was ameliorated and autophagy activity in the myocardial tissue was enhanced. Meanwhile, miR199 a-5 p expression declined and Atg5 expression increased. As predicted by bioinformatics, Atg5 was a target gene of miR199 a-5 p. CHS Ⅳa was capable of preventing myocardial hypertrophy by regulating autophagy of myocardial cells through the miR-199 a-5 p/Atg5 signaling pathway.

Overexpression of miR-130a-3p attenuates cardiomyocyte hypertrophy / 生物医学工程学杂志

This study aimed to explore the role of miR-130a-3p in cardiomyocyte hypertrophy and its underlying mechanisms. Pressure-overload induced myocardial hypertrophy mice model was constructed by thoracic aortic constriction (TAC). , norepinephrine (NE) was used to stimulate neonatal rat cardiomyocytes (NRCMs) and H9c2 rat cardiomyocytes to induce hypertrophic phenotypes. The expression of miR-130a-3p was detected in mice hypertrophic myocardium, hypertrophic NRCMs and H9c2 cells. The mimics and inhibitors of miR-130a-3p were transfected into H9c2 cells to observe the role of miR-130a-3p on the hypertrophic phenotype change of cardiomyocytes separately. Furthermore, whether miR-130a-3p regulated hypertrophic related signaling pathways was explored. The results showed that the expression of miR-130a-3p was significantly decreased in hypertrophic myocardium, hypertrophic NRCMs and H9c2 cells. After transfection of miR-130a-3p mimics, the expression of hypertrophic marker genes, atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and β-myosin heavy chain (β-MHC), and the cell surface area were notably down-regulated compared with the control group (mimics N.C. + NE group). But after transfection of miR-130a-3p inhibitor, the expression of ANP, BNP and β-MHC in H9c2 cells increased significantly, and the cell area increased further. By Western blot, it was found that the protein phosphorylation level of Akt and mTOR were down-regulated after over-expression of miR-130a-3p. These results suggest that miR-130a-3p mimics may alleviate the degree of cardiomyocyte hypertrophy, meanwhile its inhibitor can further aggravate cardiomyocyte hypertrophy. Over-expression of miR-130a-3p may attenuate cardiomyocytes hypertrophy by affecting the Akt pathway.

BMP4 Induces Cardiomyocyte Hypertrophy Through the Activation of ERK 1/2 Signaling Pathway in H9c2 Cells

Abstract Bone morphogenetic protein-4 (BMP4) is a member of the bone morphogenetic protein family which plays an important role in bone formation, inflammation and cardiac hypertrophy. The aim of this study was to investigate the underlying molecular mechanism that BMP4-induced cardiomyocyte hypertrophy. H9c2 cells were used to measure cell surface area and protein synthesis. Western blot was used to examine hypertrophic marker brain natriuretic peptide (BNP) protein expression and phosphorylation of ERK1/2. The results exhibited that cell surface area, protein synthesis and BNP protein expression were increased with BMP4 treatment. While PD98059 inhibited these effects of BMP4. In addition, BMP4 treatment increased phosphorylation of ERK1/2 in a time- and dose-dependent manner. PD98059 treatment decreased phosphorylation of ERK1/2 that was increased by BMP4. These results suggest that BMP4 induces cardiomyocyte hypertrophy through the activation of ERK1/2 cell signaling pathway.

Inhibitory effects of adenosine a1 receptor stimulation on rat myocardial hypertrophy induced by isoproterenol through tgf-β1/smad3 signal pathways / 中国药学杂志

OBJECTIVE: To observe the inhibitiory effect of adenosine A1 receptor stimulation on myocardial hypertrophy by TGF-β1/Smad3 signal pathways and myocardial energy metabolism in rats and discuss its related mechanism. METHODS: High dose isoproterrnol was subcutaneously injected into rats to establish myocardial hypertrophy model. Forty Sprague-Dawley rats were randomly divided into four groups with ten rats for each group:blank control group,isoproterenol model group, CCPA(150 μg·kg-1·min-1) treatment group.From second day after modeling,rats in CCPA group and in propranolol group were injected continuosly for eight weeks. Then the heart mass index (HMI)and left ventricular mass index (LVMI) were measured, the myocardial cells were observed under the light microscope by HE staining. The free fatty acids (FFA), lactic acids (LAC) and adenosine triphosphate (ATP) contents in myocardial tissue of rats were detected. The relative expression of TGE-β1 and Smad3 protein were determined by Western blotting. RESULTS: Compared with model group, in CCPA group, the HMI and LVMI were reduced, the conetent of FFA and LAC were decreased, the content of ATP was increased,and the relative expression of TGF-β1/Smad3 of CCPA group was decreased. CONCLUSION: When the adenosine A1 receptor was stimulated, it can improve the energy metabolism of myocardial hypertrophy, and restrain TGF-β1/Smad3 signal pathway, thus it play a protective role in the myocardial cells by reducing the expression of TGF-β1 and Smad3 protein.

Cardioprotective effect of Danshen injectable powder on pressure overload-induced ventricular remodeling in rats and isoproterenol induced myocardial injury in mice / 中国药理学与毒理学杂志

OBJECTIVE To determine the effects of Danshen injectable powder on myocardial remodeling in pressure overload rats and isoproterenol(ISO)injection mice.METHODS SD Rats were subject to abdominal aortic constriction(AAC)surgery to develop pressure overload.Therapeutic effect of Danshen injectable powder was assessed six weeks after AAC surgery. The lactic dehydrogenase (LDH) and creatine kinase (CK) levels in serum, biometric, echocardiographic parameters, interstitial fibrosis, the expression of DJ-1 and SOD2 were then measured. The myocardial impairment in mice was induced by ISO injection. LDH and CK in serum, biometric, interstitial fibrosis were measured to investigate the cardioprotective effect of Danshen injectable powder. Matrix-assisted laser desorption mass spectrometry imaging(MALDI-MSI)was used to detect the changes of 60-1000 Da molecules in mice heart tissue. RESULTS In AAC rats, we observed compensatory hypertrophy and perivascular fibrosis,however cardiac function had not progressed to deterioration.The levels of LDH and CK were decreased significantly in the Danshen injectable powder groups(P<0.05,P<0.05).Danshen injectable powder could alleviate the perivascular collagen deposits but not cardiac hypertrophy in AAC rats. Furthermore,Danshen injectable powder enhanced the expression levels of SOD2 and DJ-1 in cardio-myocytes (P<0.05, P<0.01). In ISO injection mice, the levels of HWI and LDH were decreased signifi-cantly in drug treatment group compared with model group (P<0.01, P<0.01). In the MALDI-MSI of mice heart section,Danshen injectable powder can improve the reduction of energy metabolism-related substances including adenosine, creatine and ADP induced by ISO impairment. CONCLUSION Danshen injectable powder can attenuate perivascular fibrosis and improve the expression of anti-oxidative stress-related proteins SOD2,DJ-1 in the rats with pressure overload-induced left ventricular remodeling.Danshen injectable powder has cardioprotective effect on ISO impairment in mice which is probably related to improvement of energy metabolism.

Effects of High Intensity Interval Training on the Activity of the Myocardial Mitochondrial Respiratory Chain Complex of Rats / 中国运动医学杂志

Objective To explore the heart function and activity of the mitochondrial respiratory chain complex of rats with myocardial hypertrophy induced by the long-term high-intensity interval training(HIIT).Methods Ninety Wistar rats were randomly divided into an HIIT group,a moderate intensity continuous training(MICT) group and a rest control(RC) group,with each group allocated three subgroups according to the observation time(2,6 and 10 weeks),9 groups altogether(n=10 in each group).Each group was given intervention as their names implied.Then,the heart function was measured using the ultrasoundcardiogram,and the body weight as well as the weight of the heart was weighted.The myocardium mitochondria were extracted using the differential centrifugation after homoge nation to detect the activity of the myocardial and mitochondrial citrate synthase (CS),the activities of the respiratory chain complex C Ⅰ ～CⅣ as well as myocardial protein expression of peroxisome proliferator-activated receptor gamma coactivator 1α (PGC-1 α),α-myosin heavy chain (α-MHC),β-MHC,atrial natriuretic factor(ANF) and brain natriuretic peptide(BNP).Results The myocardial hypertrophy was found in HIIT and MICT groups after 1-week and 9-week intervention respectively.At the 2nd and 10th week,no significant differences were found in the heart function,respiratory chain complex activity and protein expression of all three groups(P＞0.05).At the 6th week,the left ventricular ejection fraction,left ventricular fractional shortening,myocardial α-MHC protein expression,and the activities of respiratory chain complex C Ⅰ,C Ⅲ and C Ⅳ of HIIT group were significantly lower while the myocardial β-MHC and BNP protein expression were significantly higher than those of RC and MICT groups(P＜0.05).Conclusion Long-term HIIT but not MICT can induce temporarily pathological myocardial hypertrophy and reduced heart function in Wistar rats,and the mechanism might be related to the downregulation of the myocardial mitochondrial respiratory chain complex activity.

Effect of tempol on NF-κB signaling pathway in the rat model of myocardial hypertrophy / 中国比较医学杂志

Objective To investigate the effects of 2, 2, 6, 6-tetramethyl-4-piperidinol (tempol) on NF-κB signaling pathway of myocardial hypertrophy in rats. Methods The rat model of myocardial hypertrophy was established by intraperitoneal injection of isoprenaline (ISO) (5 mg/kg, twice per day, 2 weeks). A total of 42 male SD rats were randomly divided into 3 groups, including the control group, myocardial hypertrophy model group (ISO + sterile saline) and tempol treatment group (ISO + tempol) [tempol 100 mg/ (kg·d), 8 weeks]. Eight weeks after the corresponding drug intervention, the heart weight index (HWI) and left ventricular weight index (LVWI) were determined. Morphology and fibrosis of the myocardium were observed by HE staining, and the myocardial fibrosis of the rats was observed by Masson staining. The mRNA levels of TNF-α and IL-6 in the rat myocardial tissues were detected by qRT-PCR, and the expression levels of IκBα, p-p65 and p65 were detected by Western blot. Results Compared with the control group, the HWI and LVMI, mRNA levels of TNF-α and IL-6, and expression of p-p65/p65 in the model group were significantly increased (P＜ 0. 05), while the expression level of IκBα, an NF-κB inhibitory protein was significantly decreased (P＜0. 05). The pathological examination of the myocardial tissues showed thickening and disordered arrangement of myocardial fibers, and increased cross-sectional area of the myocardial fibers. The pathology by Masson staining showed aggravated myocardial fibrosis and increased collagen fibers in the myocardial interstitium. Compared with the model group, the HWI and LVMI, the mRNA levels of TNF-α and IL-6, and the expression of p- p65/p65 of the tempol group were significantly decreased (P＜ 0. 05), while the expression level of IκBα was significantly increased (P＜ 0. 05). HE staining showed that the degrees of myocardial disarrangement and cardiomyocyte hypertrophy were decreased. Meanwhile, Masson staining showed that the extent of myocardial fibrosis was reduced, and the interstitial collagen fibers were decreased. Conclusions Tempol can improve the isoprenaline-induced myocardial hypertrophy, which may be closely related with the inhibition of the activity of NF-κB signaling pathway.

The effect of metoprolol on Calpain I and CaN signaling pathway in pressure overload induced myocardial hypertrophy / 天津医药

Objective To study the mechanism of metoprolol preventing pressure overload induced myocardial hypertrophy through inhibiting calcineurin (CaN) and CalpainⅠsignaling pathway in rat model of coarctation of abdominal aorta. Methods Thirty SD rats were used for hypertension rat model induced by coarctation of suprarenal abdominal aorta. Model rats were divided into three groups, sham operation group (n=10), abdominal aortic coarctation group (n=9) and metoprolol group (n=9). The changes of blood pressure [systolic blood pressure (SBP) and diastolic blood pressure (DBP)] and myocardial hypertrophy [the ratio of left ventricular mass/ body mass (LVW/BW)] were measured. RT-PCR was used to detect the expression of CaN mRNA, and Western blot assay was used to detect expressions of CaN and CalpainⅠproteins. The activity of CaN enzyme was detected and compared between three groups. Results Compared with the sham-operated sham operation group, values of SBP, DBP, LVW/BW, protein expressions and activities of CaN mRNA, CaN and CalpainⅠwere significantly increased in operation group (P<0.05). There were no significant differences in SBP and DBP between metoprolol-treated group and the operation group (P>0.05). Furthermore, values of SBP and DBP were significantly higher in metoprolol-treated group than those of sham group (P<0.05). Compared with operation group, values of LVW/BW, the protein expression and activity of CaN mRNA and Calpain Ⅰwere significantly decreased in metoprolol group (P<0.05), which were no significant differences compared with sham group. Conclusion Metoprolol prevents myocardial hypertrophy in abdominal aorta coarctative rats, through inhibiting CalpainⅠand CaN signaling pathways.

Protective effect of Dendrobium candidum on isoproterenol induced cardiac hypertrophy in rats / 中国中药杂志

To study the effect and mechanism of Dendrobium candidum on isoproterenol-induced myocardial hypertrophy in rats, 60 healthy SD rats(30 males and 30 females) were randomly divided into 5 groups(12 in each group): normal group, model group, three D. candidum preventive administration groups(0.09, 0.18, 1.1 g·kg⁻¹). Except for the normal group, rats of other groups were injected back subcutaneously with ISO(5 mg·kg⁻¹) for 10 consecutive days. At the same time, preventive administration groups began to give different doses of the sample for 30 days and model group began to give normal saline. Left ventricular systolic pressure(LVSP) was measured in each group by common carotid artery cannulation, and the left ventricle(LW)/tibia length, heart weight index(HWI) and myocardial hydroxyproline(Hydro) content were calculated. Myocardial tissue HE staining and Masson staining were used to observe the myocardial structure and the degree of myocardial fibrosis respectively. Atrial natriuretic peptide(ANP), brain natriuretic peptide(BNP), and cardiac troponin I(cTN-I) concentration were measured by enzyme-linked immunosorbent assay(ELISA). The results showed that as compared with the normal group, the levels of ANP, BNP and cTN-I in plasma were significantly increased in ISO-induced hypertrophic rats; as compared with the model group, D. candidumcan inhibit ISO-induced ventricular pressure and ventricular hypertrophy, reduce myocardial collagen synthesis, improve myocardial fibrosis and ventricular remodeling, and significantly down-regulate ANP, BNP and cTN-I levels in plasma. This study shows that D. candidum has a protective effect on isoproterenol-induced cardiac hypertrophy.

Etanercept protects rat cardiomyocytes against hypertrophy by regulating inflammatory cytokines secretion and cell apoptosis

We aimed to investigate the effect of etanercept, a tumor necrosis factor-α (TNF-α) inhibitor, on rat cardiomyocyte hypertrophy and its underlying mechanism. Primary neonatal rat cardiomyocytes were isolated from Sprague-Dawley rats. The model of rat cardiomyocyte hypertrophy was induced by endothelin, and then treated with different concentrations of etanercept (1, 10, and 50 μM). After treatment, cell counts, viability and cell apoptosis were evaluated. The mRNA levels of myocardial hypertrophy marker genes, including atrial natriuretic factor (ANF), matrix metalloproteinase (MMP)-9 and MMP-13, were detected by qRT-PCR, and the expressions of apoptosis-related proteins (Bcl-2 and Bax) were measured by western blotting. The protein levels of transforming growth factor-β1 (TGF-β1), interleukin (IL)-1β, IL-6, leukemia inhibitory factor (LIF) and cardiotrophin-1 (CT-1) were determined using enzyme linked immunosorbent assay (ELISA) kits. In the present study, TNF-α level in cardiomyocytes with hypertrophy was significantly enhanced (P<0.05). Compared to the model group, cell number and viability were significantly increased and ratio of apoptotic cells was reduced by etanercept (P<0.05, P<0.01, or P<0.001). In addition, etanercept remarkably reduced the mRNA levels of ANF, MMP-9 and MMP-13, inhibited the expression of Bax, and increased the expression of Bcl-2 compared to the model group (P<0.05). ELISA results further showed that etanercept lowered the levels of IL-1β, IL-6, LIF and CT-1 but not TGF-β1 compared to the model group (P<0.05). Etanercept may protect rat cardiomyocytes from hypertrophy by inhibiting inflammatory cytokines secretion and cell apoptosis.

Effect of Shexiang Baoxin Pills on isoprenaline-induced myocardial cell hypertrophy and Cx43 expression / 中南大学学报(医学版)

Objective:To observe the effects of Shexiang Baoxin Pill (SBP) on isoprenaline (Iso)-induced changes in myocardial cell volume,shape,and connexin 43 (Cx43) expression.Methods:HgC2 myocardial cells were randomly divided into a control group,a Iso group and a Iso+SBP group.After 72 h of culture,the average surface area of HgC2 cells was measured under phase contrast microscope.Bicinchoninic acid (BCA) protein assay was carried out to determine the concentration of proteins.The survival rate of myocardial cells was measured by methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay,and the Cx43 expression was detected by Western blot.Results:The mean surface area and Cx43 concentration in Iso-treated myocardial cells were increased under the phase contrast microscope (P<0.05).Compared with the Iso group,the mean surface area was decreased,and the Cx43 concentration was reduced in the Iso+SBP group (both P<0.05).Compared with the control group,the Cx43 expression was obviously down-regulated in the H9C2 cells of the Iso group (P<0.05);while compared with the Iso group,the Cx43 expression was obviously up-regulated in the Iso+SBP group (P<0.05).Conclusion:Shexiang Baoxin Pills can prevent Iso-induced myocardial hypertrophy and down-regulate Cx43 expression.

Role of nucleolin on myocardial hypertrophy and fibrosis in type II diabetic cardiomyopathy mice / 中国病理生理杂志

AIM: To investigate the effect of nucleolin on diabetic cardiomyopathy in mice.METHODS: A type II diabetic cardiomyopathy mouse model was prepared using a cardiac-specific nucleolin-overexpressing transgenic mice.The mice were divided into wild-type mouse control group, nucleolin transgenic mouse control group, wild-type mouse diabetes group and nucleolin transgenic mouse diabetes group.Wheat germ agglutinin (WGA) fluorescent dye, Masson staining and PowerLab system detection were used to further clarify the role of nucleolin on cardiac hypertrophy, fibrosis and cardiac function in type II diabetic cardiomyopathy mice.RESULTS: Compared with wild-type mouse control group, no significant increase in blood glucose level was found, while genetical myocardial cell hypertrophy was significantly attenuated in nucleolin transgenic mouse diabetes group.The collagen fibers were also significantly reduced, and hemodynamic indexes ± dp/dtmax, left ventricular end-diastolic pressure, left ventricular systolic pressure and heart rate were also improved.The above differences were statistically significant.CONCLUSION: Nucleolin may reduce the occurrence of myocardial hypertrophy and fibrosis, thus improving the cardiac function of diabetic cardiomyopathy mice.

Metformin inhibits myocardial hypertrophy by up-regulating glutathione-S-transferase μ2 / 中国临床药理学与治疗学

AIM:To observe the effect of metformin on the expression of GSTM2 in spontaneously hypertensive rats,and to investigate the mechanism of the reversal of myocardial hypertrophy by metformin.METHODS:Sixteen weeks old WistarKyoto (WKY) and spontaneously hypertensive rats (SHR) were used as the experimental control.Eight weeks old WKY and SHR were administered to metformin (Met) continuously for 8 weeks as the experimental group.Systolic pressure of rats was regularly determined by NIBP instrument of heart rate and blood pressure.The hemodynamic parameters were tested by BL-420 biological experimental system and 4 track physiological recorders.The weights of left ventricle and rats were collected to calculate the left ventricular mass index.The activity of GSTM2 enzyme in left ventricle was detected by Enzyme-linked immunosorbent assay (ELISA).The protein expression of GSTM2 and p47phox and Nox4 in left ventricle were investigated by Western blot.The O2·-levels were measured by staining with dihydroethidium (DHE).RESULTS:Compared with the experimental control,the blood pressure and left ventricular mass index and left ventricular end-diastolic pressure (LVEDP) increased in SHR;the maximal rate of increase and decrease of left-ventricle pressure development (± dp/dt max) decreased significantly in SHR;the protein expression and enzyme activity of left ventricular GSTM2 were significantly decreased;the expression of p47phox,Nox4 and the generation of O2·-were significantly increased in the left ventricles of SHR;the value of P was less than 0.01 and the difference was statistically significant.Compared with the SHR group,the SHR were administered with metformin (Met) continuously for 8 weeks.The left ventricular mass index and left ventricular end-diastolic pressure(LVEDP) decreased observably in SHR administration group;the maximal rate of increase and decrease of left-ventricle pressure development(± dp/dt max) increased in SHR administration group;the protein expression and enzyme activity of left ventricular GSTM2 were significantly increased in SHR administration group.the expression of p47phox,Nox4 and the generation of O2·-was significantly decreased in the left ventricles of SHR administration group;the value of P was less than 0.01 and the difference was statistically significant.CONCLUSION:Metformin can significantly reverse the myocardial hypertrophy in SHR,which might be associated with the up-regulation of GSTM2 expression,decrease the expression of p47phox,Nox4 and O2·-generation,elimination of oxidative stress.

Protection of MICU1 against myocardial hypertrophy induced by angiotensin Ⅱ / 解放军医学杂志

Objective To investigate the role of mitochondrial calcium uptake 1 (MICUI) in myocardial hypertrophy of mice and underlying mechanism.Methods The model of myocardial hypertrophy was established via incubation of mouse cardiac myocytes (MCM) with 300nmol/L angiotensin Ⅱ (Ang Ⅱ) for 48 hours in vitro.After that,MICU1 specific small interfering RNA (siRNA) was delivered to knockdown MICU1 levels in MCM.On the other hand,adenovirus-mediated over-expression of MICU 1 was transfected into MCM.Accordingly,the expressions of ANP and BNP in myocardial cells were measured by qRT-PCR.Mitochondrial membrane potential and ATP contents were detected byJC-1 assay kit and ATP assay kit,respectively.Then,Western blotting and qRT-PCR were used to detect the levels of MICU1 in myocardial cells.The mitochondrial Ca2+ contents were measured via atomic absorption flame spectroscopy.The size of myocardial cells was determined by α-actinin staining.Results Mitochondrial membrane potential and ATP contents in hypertrophic cardiomyocytes induced by Ang Ⅱ were both decreased.Meanwhile,myocardial hypertrophy significantly increased mitochondrial Ca2+ contents but decreased MICU1 levels.With the method of genetic intervention,we found that MICUI deficiency exacerbated mitochondrial Ca2+ overload,increased cell surface and elevated the expression of BNP.Conversely,the overexpression of MICU1 obviously decreased mitochondrial Ca2+ overload,cell surface of MCM and expressions of ANP and BNP.Conclusion MICU1 alleviates Ang Ⅱ-induced myocardial hypertrophy via inhibiting mitochondrial Ca2+ overload.

Role of miRNA-204 targeted LC3B in Ang Ⅱ induced myocardial hypertrophy / 重庆医学

Objective To explore the effects of miRNA-204 targeted LC3B expression on Ang Ⅱ induced cardiomyocytes hypertrophy.Methods The primary neonatal rat cardiomyocytes served as the research objects and divided into the control group,AngⅡ group,combination-treated group 1 (cardiomyocytes were given Ang Ⅱ stimulation,meanwhile infected by negative control lentivirus vector),combination-treated group 2 (cardiomyocytes were given Ang Ⅱ stimulation,meanwhile infected by lentivirus carrying miRNA-204 overexpression vector) according to different treatments.About 48 h to 72 h after intervention treatment,the cardiomyocyte hypertrophy change was detected by confocal microscopy,the expression of miRNA-204 was analyzed by real time PCR,the protein expression of LC3B was measured by Western blot and targeted gene of miRNA-204 was demonstrated by dual-luciferase reporter assay system.Results Compared with the control group,the cardiomyocyte relative surface area in the Ang Ⅱ group was significantly enlarged,the protein expression of LC3B was significantly increased,the expression of miRNA-204 was upregulated,the differences were statistically significant (P＜0.05).Whereas comparing the combination-treated group 1 with combination-treated group 2,the protein expression of LC3B in the latter was down-regulated and the cell area was reduced (P＜0.05).The further luciferase activity report gene experiment results suggested that miRNA-204 was able to bind to LC3B 3'-UTR and decreased the luciferase activities (P＜0.05),but not to bind its mutated fragment for inactivating luciferase activity(P＞0.05).Conclusion miRNA-204 is able to inhibit Ang Ⅱ induced cardiomyocytes hypertrophy,its action is realized by targeting the expression of LC3B.