Electroacupuncture improves myocardial fibrosis in heart failure rats by attenuating ECM collagen deposition through modulation of TGF-β1/Smads signaling pathway

Background: To explore the effects of electroacupuncture on cardiac function and myocardial fibrosis in rat models of heart failure, and to elucidate the underlying mechanism of electroacupuncture in heart failure treatment. Methods: Healthy male Sprague-Dawley rats were allocated into three groups: Sham group, Model group, and electroacupuncture (Model + EA) group, with each group comprising 8 rats. The model underwent a procedure involving the ligation of the left anterior descending coronary artery to induce a model of heart failure. The Model + EA group was used for 7 consecutive days for electroacupuncture of bilateral Shenmen (HT7) and Tongli (HT5), once a day for 30 min each time. Left ventricular parameters in rats were assessed using a small-animal ultrasound machine to analyze changes in left ventricular end-diastolic volume, left ventricular end-systolic volume, left ventricular ejection fraction, and left ventricular fractional shortening. Serum interleukin-1β (IL-1β), cardiac troponin (cTn), and N-terminal brain natriuretic peptide precursor levels were measured using ELISA. Histopathological changes in rat myocardium were observed through HE staining, while collagen deposition in rat myocardial tissue was assessed using the Masson staining method. Picro sirius red staining, immunohistochemical staining, and RT-qPCR were utilized to distinguish between the various types of collagen deposition. The expression level of TGF-β1 and SMAD2/3/4/7 mRNA in rat myocardial tissues was determined using RT-qPCR. Additionally, western blot analysis was conducted to assess the protein expression levels of TGF-β1, SMAD3/7, and p-SMAD3 in rat myocardial tissues. Results: Compared with the Sham group, the left ventricular ejection fraction and left ventricular fractional shortening values of the Model group were significantly decreased (P < 0.01);the left ventricular end-diastolic volume and left ventricular end-systolic volume values were remarkably increased (P < 0.01);serum N-terminal brain natriuretic peptide precursor content was increased (P < 0.01);serum IL-1β and cTn levels were increased (P < 0.01);myocardial collagen volume fraction were increased (P < 0.01);and those of the expression of TGF-β1 and SMAD2/3/4 mRNA was increased (P < 0.01);the expression of SMAD7 mRNA was decreased (P < 0.01);the protein expression levels of TGF-β1, SMAD3, and p-Smad3 were increased (P < 0.01);the protein expression level of SMAD7 was decreased (P < 0.01) in the Model group. Compared to the Model group, the expression levels of the proteins TGF-β1, SMAD3, and p-Smad3 in myocardial tissue were found to be decreased (P < 0.01), and the expression level of the protein SMAD7 was found to be increased (P < 0.01) in the Model + EA group;the collagen volume fraction and deposition of type Ⅰ /Ⅲ collagen were decreased (P < 0.01) in the Model + EA group. Conclusion: Electroacupuncture alleviates myocardial fibrosis in rats with heart failure, and this effect is likely due to attributed to the modulation of the TGF-β1/Smads signaling pathway, which helps reduce collagen deposition in the extracellular matrix.

Atorvastatin ameliorated myocardial fibrosis in db/db mice by inhibiting oxidative stress and modulating macrophage polarization

BACKGROUND People with diabetes mellitus(DM)suffer from multiple chronic complications due to sustained hyperglycemia,especially diabetic cardiomyopathy(DCM).Oxidative stress and inflammatory cells play crucial roles in the occurrence and progression of myocardial remodeling.Macrophages polarize to two distinct phenotypes:M1 and M2,and such plasticity in phenotypes provide macrophages various biological functions.AIM To investigate the effect of atorvastatin on cardiac function of DCM in db/db mice and its underlying mechanisms.METHODS DCM mouse models were established and randomly divided into DM,atorvastatin,and metformin groups.C57BL/6 mice were used as the control.Cardiac function was evaluated by echocardiography.Hematoxylin and eosin and Masson staining was used to examine the morphology and collagen fibers in myocardial tissues.The expression of transforming growth factor-β1(TGF-β1),tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β),M1 macrophages(iNOS^(+)),and M2 macrophages(CD206^(+))were demonstrated by immunohistochemistry and immunofluorescence staining.The levels of TGF-β1,IL-1β,and TNF-αwere detected by ELISA and real-time quantitative polymerase chain reaction.Malondialdehyde(MDA)concentrations and superoxide dismutase(SOD)activities were also measured.RESULTS Treatment with atorvastatin alleviated cardiac dysfunction and decreased db/db mice. The broken myocardialfibers and deposition of collagen in the myocardial interstitium were relieved especially by atorvastatin treatment.Atorvastatin also reduced the levels of serum lactate dehydrogenase, creatine kinase isoenzyme, and troponin;lowered the levels of TGF-β1, TNF-α and IL-1β in serum and myocardium;decreased the concentration of MDAand increased SOD activity in myocardium of db/db mice;inhibited M1 macrophages;and promoted M2macrophages.CONCLUSION Administration of atorvastatin attenuates myocardial fibrosis in db/db mice, which may be associated with theantioxidative stress and anti-inflammatory effects of atorvastatin on diabetic myocardium through modulatingmacrophage polarization.

Liraglutide Suppresses Myocardial Fibrosis Progression by Inhibiting the Smad Signaling Pathway

Objective Liraglutide is a commonly used hypoglycemic agent in clinical practice,and has been demonstrated to have protective effects against the development of cardiovascular disease.However,its potential role in myocardial fibrosis remains unexplored.The present study aims to assess the impact of liraglutide on the activation of cardiac fibroblasts.Methods Primary rat adult fibroblasts were isolated,cultured,and randomly allocated into 4 groups:control group,transforming growth factor beta1(TGFβ1)stimulation group,liraglutide group,and TGFβ1+liraglutide group.Fibroblast activation was induced by TGFβ1.Cell proliferation activity was assessed using the CKK-8 kit,and cellular activity was determined using the MTT kit.Reverse transcrition-quantitative polymerase chain reaction(RT-qPCR)was utilized to quantify the level of collagen transcription,immunofluorescence staining was performed to detect the expression level of type III collagen andα-smooth muscle protein(α-SMA),and immunoblotting was conducted to monitor alterations in signal pathways.Results The addition of 10,25,50 and 100 nmol/L of liraglutide did not induce any significant impact on the viability of fibroblasts(P>0.05).The rate of cellular proliferation was significantly higher in the TGFβl stimulation group than in the control group.However,the treatment with 50 and 100 nmol/L of liraglutide resulted in the reduction of TGFβl-induced cell proliferation(P<0.05).The RT-qPCR results revealed that the transcription levels of type I collagen,type III collagen,andα-SMA were significantly upregulated in the TGFβl stimulation group,when compared to the control group(P<0.05).However,the expression levels of these aforementioned factors significantly decreased in the TGFβl+liraglutide group(P<0.05).The immunofluorescence staining results revealed a significant increase in the expression levels of type III collagen andα-SMA in the TGFβl stimulation group,when compared to the control group(P<0.05).However,these expression levels significantly decreased in the TGFβl+liraglutide group,when compared to the TGFβl stimulation group(P<0.05).The Western blotting results revealed that the expression levels of phosphorylated smad2 and smad3 significantly increased in the TGFβl stimulation group,when compared to the control group(P<0.05),while these decreased in the TGFβl+liraglutide group(P<0.05).Conclusion Liraglutide inhibits myocardial fibrosis development by suppressing the smad signaling pathway,reducing the activation and secretion of cardiac fibroblasts.

Paeoniflorin Attenuates Myocardial Fibrosis in Isoprenaline-induced Chronic Heart F ailure Rats via Inhibiting P38 MA PK Pathway

Paconiflorin(Pae)is a monoterpenoid glycoside compound and has many biological activitics,such as immunosuppression,anti-inflammation and anti-cell proliferation.However,the effects and mechanisms of Pae on chronic heart failure(CHF)remain unclear.This study was conducted to assess the effects and mechanisms of Pae on myocardial fibrosis in isoprenaline(Iso)-induced CHF rats.Pae(20 mgkg)was intragastrically administrated to CHF rats for 6 weeks.Cardiac structure and function were assessed.The protein and mRNA levels of transforming growth factorβ1(TGF-β1)and p38 were detected.C ompared to Iso group,Pae could alleviate myocardial fbrosis and improve cardiac function in CHF rats.The levels of collagen volume fraction(13.75%+3.77%vs.30.97%+4.22%,P<0.001)and perivascular collagen volume area(14.32%+2.50%v8.28.31%+3.16%,P<0.001)were significantly reduced in Pae group as compared with those in Iso group.The expression of TGF-BI protein(0.30+0.07 vs.0.66+0.07,P<0.05)and mRNA(3.51+0.44 vs.7.58+0.58,P<0.05)decreased significantly in Pac group as compared with that in Iso group.The expression of p38 protein(0.36+0.12 vs.0.81+0.38,P<0.05)and mRNA(3.84+0.05 vs.4.40+0.17,P<0.05)also decreased markedly in Pae group as compared with that in Iso group.Pae could attenuate myocardial fibrosis and improve cardiac function in CHF rats by down-regulating the p38 MAPK signaling pathway.

Taurine Inhibits Myocardial Fibrosis via PKC-ERK1/2 Signaling Pathways

Previous studies have demonstrated the important role of taurine in inhibiting proliferation of myofibrob lasts（myoFb） and myocardial fibrosis. However, the underlying mechanisms are unclear. The present study was de signed to shed light on this issue through exploring the signal pathways via in vitro experiments. Angiotension II （AngII） treatment significantly increased myoFb proliferation and the levels of collagens I and III（P〈0.05）, whereas taurine, PKCα（PKC： protein kinase C） specific inhibitor L-threo-dihydro-sphingosine（D4681）, ERK1/2 inhibitor （PD98095） abrogated myoFb proliferation and collagen levels（P〈0.05, P〈0.01, respectively）, and increased the G0/G1 phase rate and decreased S phase rate. Immunocytochemistry, confocal fluorescence staining and image analy sis showed that taurine could inhibit the translocation and expression of p-PKCαin membrane, and then inhibit nuc lear translocation and expression of p-ERK1/2. These results have statistically significant differences compared with those of AngII group（P〈0.01）. Western blot results also show that taurine could inhibit the protein expression of p-PKCα and p-ERK1/2. We used p-PKCα specific inhibitor D4681 in order to elucidate the relationship between p-PKCα and p-ERK1/2 in signal transduction pathways. Finally, the results show that the protein expression of p-ERK1/2 and nuclear translocation were suppressed in D4681 group.

Association of electrocardiographic markers with myocardial fibrosis as assessed by cardiac magnetic resonance in different clinical settings

BACKGROUND Cardiac magnetic resonance(CMR)is a unique tool for non-invasive tissue characterization,especially for identifying fibrosis.AIM To present the existing data regarding the association of electrocardiographic(ECG)markers with myocardial fibrosis identified by CMR-late gadolinium enhancement(LGE).METHODS A systematic search was performed for identifying the relevant studies in Medline and Cochrane databases through February 2021.In addition,we conducted a relevant search by Reference Citation Analysis(RCA)(https://www.referencecitationanalysis.com).RESULTS A total of 32 studies were included.In hypertrophic cardiomyopathy(HCM),fragmented QRS(fQRS)is related to the presence and extent of myocardial fibrosis.fQRS and abnormal Q waves are associated with LGE in ischemic cardiomyopathy patients,while fQRS has also been related to fibrosis in myocarditis.Selvester score,abnormal Q waves,and notched QRS have also been associated with LGE.Repolarization abnormalities as reflected by increased Tp-Te,negative Twaves,and higher QT dispersion are related to myocardial fibrosis in HCM patients.In patients with Duchenne muscular dystrophy,a significant correlation between fQRS and the amount of myocardial fibrosis as assessed by LGE-CMR was observed.In atrial fibrillation patients,advanced inter-atrial block is defined as P-wave duration≥120 ms,and biphasic morphology in inferior leads is related to left atrial fibrosis.CONCLUSION Myocardial fibrosis,a reliable marker of prognosis in a broad spectrum of cardiovascular diseases,can be easily understood with an easily applicable ECG.However,more data is needed on a specific disease basis to study the association of ECG markers and myocardial fibrosis as depicted by CMR.

Effects of Ligustrazine on Myocardial Fibrosis in Rats with Pressure Overload

Objective: To investigate the effects of ligustrazine (Li) on myocardial fibrosis in rats with pressure overload. Methods: Pressure overload rat models were established by constricting the abdominal a-orta. Sixty-three SD rats were divided into 3 groups: Sham operated group (SOG, n = 21), operated group (OG, n = 21) and operated combined with ligustrazine group (OG+Li, n = 21). Each group was randomly assigned to seven time points: The 1st, 2nd, 4th, 7th, 14th, 21st and 30th day after operation. Three rats were included in each time point. Serial sections of cardiac tissues were examined and the morphological or morphometric analysis of the SOG, OG and OG+Li done by histopathological and computer image analyzer technique. Results: (1) It showed that there were reactive fibrosis (from the 4th day on after operation) and reparative fibrosis (from the 21st day on after operation) in the OG, while myocardial fibrosis in the OG+Li was alleviated. Though reactive fibrosis (from the 21st day on after operation) was shown, reparative fibrosis wasn't seen. (2) Perivascular collagen area (PVCA) in the OG (2. 09±0. 45) was significantly higher than SOG (0. 83±0.06) from the 1st day on after operation and then steadily increased, while in the OG+Li (1.16±0.06), it was significantly lower than OG at the same time; collagen volume fraction (CVF) in the OG (3.08±0. 56) significantly increased compared with the SOG (2. 78±0. 64) from the 2nd day on after operation and showed a trend of rapid ascending from the 21st day on after operation; and in the OG + Li (4.69±0.85), it was significantly decreased compared with the OG (7.56±0.88) from the 21st day on after operation, with all P<0.05. Conclusion: Ligustrazine could alleviate and postpone the accumulation of myocardial collagen and has protective effects on the heart.

Study on key genes and pathways of myocardial fibrosis and prediction of effective traditional Chinese medicine

Objectives:Bioinformatics was applied to screen the key genes of Myocardial fibrosis,explore its pathogenesis and predict the potential traditional Chinese medicines for the treatment of Myocardial fibrosis.Methods:Based on raw data of gene chip GSE59437 from gene expression database(GEO),myocardial tissue samples from 3 control mice and 3 mice treated with angiotensin II-induced myocardial fibrosis were included.Using R language processing data and screening of gene express significant differences(DEG),use a database of DAVID and the R language finish Gene Ontology(GO)annotation and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway enrichment for differences gene,using the STRING database structure protein protein interactions(PPI)networks,using Cytoscape software visualization and use the MCODE plug-in screening key function modules in the network.Coremine Medical database was used to map the key genes,construct the gene-Chinese medicine network,and screen the traditional Chinese medicines for the treatment of myocardial fibrosis.Results:208 DEGs were screened,94 of which were up-regulated and 114 were down-regulated.DEGs is mainly involved in a variety of biological processes such as extracellular matrix remodeling,collagen fiber deposition and lipid metabolism disorders.KEGG pathway enrichment involves Platelet activation,Oxytocin signaling pathway,Insulin secretion,ECM-receptor interaction,GnRH signaling pathway,TNF signaling pathway and other signaling pathways.Key modules of PPI network including:CTGF,TIMP1,SPP1,SERPINE1,COL3A1,POSTN and FOS.The potential traditional Chinese medicines for the treatment of myocardial fibrosis are Astragalus membranaceus(Fisch.),Lepidium apetalum Willd and Salvia miltiorrhiza Bge.Conclusion:Myocardial fibrosis is a complex pathological process,and the genes related to the imbalance of extracellular matrix synthesis and degradation and excessive deposition of collagen fibers play an important role in this process.This study provides a scientific reference for further exploring the pathogenesis of myocardial fibrosis,looking for therapeutic targets and potential therapeutic traditional Chinese medicines.

Effect of Candesartan Combined with Rosuvastatin on Myocardial Fibrosis in Rats with Alcoholic Cardiomyopathy by Mediating LOX-1 Expression

Objective:To analyze the effect of candesartan and rosuvastatin on myocardial fibrosis in rats with alcoholic cardiomyopathy by mediating the expression of lectin-like oxidized low-density lipoprotein receptor-1(LOX-1).Methods:The rats were selected as experimental samples,and these rats were randomly divided into observation group and alcohol feeding group(abbreviated as"alcohol group")and desartan combined with rosuvastatin intervention+alcoholic cardiomyopathy group(Referred to as the"intervention group"),the observation group is fed normally,the alcohol group is fed with alcohol,and the intervention group uses two drugs on the basis of the alcohol group to intervene.After 16 weeks of the three groups of experiments,analyze the results of the three groups of experiments.Myocardial structure,myocardial fibrosis and myocardial function.Results:After 16 weeks,the left ventricular short axis shortening rate(FS)and left ventricular ejection fraction in the alcohol group were lower than those in the observation group,while the collagen volume fraction(CVF)and left ventricular end-diastolic diameter(LVEDd)were higher than those in the observation group,The expression of LOX-1 in the intervention group was lower than that in the alcohol group,and the degree of fibrosis was reduced.The expression of LOX-1 in the alcohol group was higher than that in the observation group,and the degree of fiber increased.At the same time,the expression of TN-X and smad-3 protein in the alcohol group(86%±7%,83%±9%)were higher than those in the observation group(32%±10%,30%±7%),while the expression of smad-7 protein(36%±8%)was lower than that in the observation group(78%±9%),P<0.05 among the three groups of experiments,and there is statistical significance among the groups.Conclusion:Candesartan combined with Rosuvastatin can reduce myocardial fibrosis in rats with alcoholic cardiomyopathy by mediating the expression of LOX-1.

Tongxinluo Activates PI3K/AKT Signaling Pathway to Inhibit Endothelial Mesenchymal Transition and Attenuate Myocardial Fibrosis after Ischemia-Reperfusion in Mice

Objective To investigate the potential role of Tongxinluo(TXL)in attenuating myocardial fibrosis after myocardial ischemia-reperfusion injury(MIRI)in mice.Methods A MIRI mouse model was established by left anterior descending coronary artery ligation for 45 min.According to a random number table,66 mice were randomly divided into 6 groups(n=11 per group):the sham group,the model group,the LY-294002 group,the TXL group,the TXL+LY-294002 group and the benazepril(BNPL)group.The day after modeling,TXL and BNPL were administered by gavage.Intraperitoneal injection of LY-294002 was performed twice a week for 4 consecutive weeks.Echocardiography was used to measure cardiac function in mice.Masson staining was used to evaluate the degree of myocardial fibrosis in mice.Qualitative and quantitative analysis of endothelial mesenchymal transition(EndMT)after MIRI was performed by immunohistochemistry,immunofluorescence staining and flow cytometry,respectively.The protein expressions of platelet endothelial cell adhesion molecule-1(CD31),α-smoth muscle actin(α-SMA),phosphatidylinositol-3-kinase(PI3K)and phospho protein kinase B(p-AKT)were assessed using Western blot.Results TXL improved cardiac function in MIRI mice,reduced the degree of myocardial fibrosis,increased the expression of CD31 and inhibited the expression ofα-SMA,thus inhibited the occurrence of EndMT(P<0.05 or P<0.01).TXL significantly increased the protein expressions of PI3K and p-AKT(P<0.05 or P<0.01).There was no significant difference between TXL and BNPL group(P>0.05).In addition,the use of the PI3K/AKT pathway-specific inhibitor LY-294002 to block this pathway and combination with TXL intervention,eliminated the protective effect of TXL,further supporting the protective effect of TXL.Conclusion TXL activated the PI3K/AKT signaling pathway to inhibit EndMT and attenuated myocardial fibrosis after MIRI in mice.

Glycine Attenuates Myocardial Fibrosis in Myocardial Infarction in Rats Partly through Modulating Signal Transducer and Activator of Transcription 3/Nuclear Factor-κB/Transforming Growth Factor-β axis

Objective: Inflammation and fibrosis are strongly associated with each other. Glycine is present in various traditional Chinese medicines and exhibits anti-inflammatory activity. However, the effects of glycine on myocardial fibrosis(MF) in rats with myocardial infarction(MI) have not been reported. The purpose of this study is to investigate the effects of glycine therapy on MF and comprehend its underlying mechanisms. Materials and Methods: Left anterior descending artery ligation-induced MI in Sprague Dawley rats was leveraged to assess the therapeutic effects of Glycine. Rats received either normal saline or glycine(0.5 mg/g bodyweight) for 7 days. Results: Glycine upregulated cardiac ejection fraction and fractional shortening to improve cardiac function, as evaluated by echocardiography. Histological and immunohistochemical analyses demonstrated that glycine could decrease inflammatory cell infiltration and alleviate collagen deposition. Western blotting revealed that nuclear factor-κB(NF-κB)-mediated inflammatory signaling was also downregulated by glycine treatment. The expression of signal transducer and activator of transcription 3(STAT3), tumor necrosis factor-α, and transforming growth factor-β(TGF-β) was decreased significantly in the glycine-treated group compared to the model group. Thus, glycine plays a protective role against myocardial ischemia and subsequent MF. Conclusion: The protective effects of glycine were achieved partly through STAT3/NF-κB/TGF-β signaling pathway.

Involvement of Interleukin-1β/Insulin-Like Growth Factor1in Ameliorating Effects of Electroacupuncture on Myocardial Fibrosis Induced by Essential Hypertension

Objective: To investigate the effect of electroacupuncture(EA) at Neiguan(PC 6) on myocardial fibrosis in spontaneously hypertensive rats(SHRs), and to explore the contribution of interleukin-1β(IL-1β),insulin-like growth factor 1(IGF-1), and transforming growth factor β1(TGF-β1) to the effects. Methods:Nine 12-weeks-old Wistar Kyoto(WKY) male rats were employed as the normal group. Twenty-seven SHRs were equally randomized into SHR, SHR+EA, and SHR + sham groups. EA was applied at bilateral PC 6once a day 30 min per day in 8 consecutive weeks. After 8-weeks EA treatment at PC 6, histopathologic changes of collagen type Ⅰ(Col Ⅰ), collagen type Ⅲ(Col Ⅲ) and the levels of IGF-1, 1L-1β, TGF-β1,matrix metalloproteinase(MMP)-2 and MMP-9 were examined in myocardial tissure respectively. Results:After 8-weeks EA treatment at PC 6, the enhanced myocardial fibrosis in SHRs were characterized by the increased mean fluorescence intensity of Col Ⅰ and Col Ⅲ in myocardium tissue(P<0.01). All these abnormal alterations above in SHR + EA group was significantly lower compared with the SHR group(P<0.01). Meanwhile,the increased levels of IL-1β, IGF-1, TGF-β1 in serum or myocardial tissue of SHRs, diminished MMP 9mRNA expression in SHRs were also markedly inhibited after 8 weeks of EA treatment(P<0.05 or P<0.01).Furthermore, the contents of IL-1β, IGF-1, TGF-β1 in myocardial tissue were positively correlated with the systolic blood pressure and hydroxyproline respectively(P<0.01). Conclusion: EA at bilateral PC 6 could ameliorate cardiac fibrosis in SHRs, which might be mediated by regulation of 1L-1β/IGF-1-TGF-β1-MMP9 pathway.

Shenmai Injection Improves Hypertensive Heart Failure by Inhibiting Myocardial Fibrosis via TGF-β1/Smad Pathway Regulation

Objective: To study effects of Shenmai Injection on hypertensive heart failure and its mechanism for inhibiting myocardial fibrosis. Methods: Salt-sensitive(Dahl/SS) rats were fed with normal diet(0.3% Na Cl) and the high-salt diet(8% Na Cl) to observe the changes in blood pressure and heart function, as the control group and the model group. Salt-insensitive rats(SS-13BN) were fed with the high-salt diet(8% Na Cl) as the negative control group. After modeling, the model rats were randomly divided into heart failure(HF) group, Shenmai Injection(SMI) group and pirfenidone(PFD) group by a random number table, with 6 rats in each group. They were given sterilized water, SMI and pirfenidone, respectively. Blood pressure, cardiac function, fibrosis and related molecular expression were detected by sphygmomanometer, echocardiogram, enzyme linked immunosorbent assay(ELISA),hematoxylin-eosin staining, Masson staining, immunofluorescence and qPCR analysis. Results: After high-salt feeding, compared with the control and negative control group, in the model group the blood pressure increased significantly, the left ventricular ejection fraction(LVEF) and left ventricular fraction shortening(LVFS) were significantly reduced, and the serum NT-pro BNP concentration increased significantly(all P<0.05);furthermore,the arrangement of myocardial cells was disordered, the edema was severe, and the degree of myocardial fibrosis was also significantly increased(P<0.05);the protein and m RNA expressions of collagen type Ⅰ(Col Ⅰ) were up-regulated(P<0.05), and the mRNA expressions of transforming growth factor β1(TGF-β1), Smad2 and Smad3 were significantly up-regulated(P<0.05). Compared with HF group, after intervention of Shenmai Injection, LVEF and LVFS increased, myocardial morphology was improved, collagen volume fraction decreased significantly(P<0.05), and the mRNA expressions of Col Ⅰ, TGF-β1, Smad2 and Smad3, as well as Col Ⅰprotein expression, were all significantly down-regulated(all P<0.05). Conclusion: Myocardial fibrosis is the main pathological manifestation of hypertensive heart failure, and Shenmai Injection could inhibit myocardial fibrosis and effectively improve heart failure by regulating TGF-β1/Smad signaling pathway.

Tenascin-x facilitates myocardial fibrosis and cardiac remodeling through transforming growth factor-β1 and peroxisome proliferator-activated receptor γ in alcoholic cardiomyopathy

Background Tenascin-x, an extracellular matrix glycoprotein exclusively expressed in fibroblasts, can mediate fibrosis in the presence of collagen. Therefore, we have investigated its potential role in facilitating myocardial fibrosis and cardiac remodeling via the transforming growth factor-lβ1 and peroxisome proliferator-activated receptor γ（TGFβ1-PPARγ） pathway in alcoholic cardiomyopathy （ACM）.Methods Experimental animals were divided into control （group A） and tenascin-x knock-out groups （group B）receiving alcohol. Six months post treatment, cardiac ejections fraction （EF）, fractional shortening （FS）, left ventricle end-diastole internal diameter （LVEDd） and collagen column fraction （CVF） were observed. Tenascin-x, smad-3, TGFβ1,smad-7 and PPARγ protein expression levels were detected by Western blotting.Results Six months post treatment, EF and FS values were higher in group B than in group A （P 〈0.05 and P 〈0.01,respectively）, while LVEDd and CVF were lower in group B （P 〈0.05 and P 〈0.01, respectively）. Tenascin-x, smad-3 and TGFβ1 protein expression levels were higher in group A, while smad-7 and PPARY levels were lower than in group B （P〈0.01）, as measured by immunohistochemistry and Western blotting. Tenascin-x protein expression was negatively correlated with EF, FS, smad-7 and PPARγ, and positively correlated with LVEDd, CVF, smad-3, and TGFβ1 （P 〈0.001）.Conclusion Tenascin-x is an initiator of myocardial fibrosis and ACM development via upregulation of TGFβ1 and downregulation of PPARγ.

Role of microRNAs in cardiac hypertrophy, myocardial fibrosis and heart failure

MicroRNAs(miRNAs)are endogenous small non-coding RNA molecules that posttranscriptionally regulate gene expression.MiRNA expression and function in heart disease remain to be determined but modulation of miRNA expression in vivo has revealed that miRNAs play an important role in controlling heart function and structure.In fact,abnormal expression of miRNAs may initiate and contribute to the progress of heart disease.Here,we summarize the literature relating to the involvement of miRNAs in cardiac hypertrophy,myocardial fibrosis and heart failure.

Dysregulation of microRNAs in a mouse model of diabetic myocardial fibrosis

Background Myocardial fibrosis plays a critical role in the process of diabetic cardiac remolding.MicroRNAs （miRNAs） are endogenous,small non-coding RNAs that negatively regulate gene expression in diverse biological and pathological processes.However,the roles of miRNAs in myocardial fibrosis have not been well elucidated.In the present study,miRNAs profiles in the fibrotic myocardium of db/db mice and miRNAs expression in TGF-β1-stimulated mouse cardiac myofibroblasts was examined.Methods Heart function of 18-week-old db/db mice and db/m control mice was detected by echocardiography.miRNA expression profile in diabetic myocardium was detected by miRNA microarray.Quantitative real-time PCR was used to determine the expression of fibrosis-related genes and miRNA precursors of interest.Western blot was used to detect the levels of fibrosis-related proteins,activated Smad3 and total Smad3.Results The result of echocardiography showed that left ventricular systolic and diastolic function was impaired in 18-week-old db/db mice without significant change of ejection fraction （EF） and fractional shortening （FS）.Fibrosis-related genes expression was upregulated and the amount of phosphorylated Smad3 was increased significantly in the diabetic myocardium.miRNAs dysregulation was shown in diabetic myocardium,sixty-eight miRNAs,including miR-208b,miR-29b,miR-26b and miR-30e,were increased over two-fold,meanwhile,sixty-two miRNAs were decreased more than two-fold in the myocardium of db/db mice compared to db/m controls.In parallel with a significant upregulation of Col1a1,Col3a1 and CTGF miRNA expression,miR-208b,miR-29b,miR-26b and miR-30e precursors were also shown to be upregulated in TGF-β1-induced C57bl/6 mouse cardiac myofibroblasts.Conclusions microRNAs were dysregulated in diabetic myocardium,with the activation of TGF-β/smad3 pathway,contributing to diabetic myocardial fibrosis.

Effect of Sodium Ferulate on Myocardial Ischemia Fibrosis Induced by Isoproterenol

We examined whether the powerful sodium ferulate（SF） could improve myocardial ischemia fibrosis degree and gain the information of myocardial energy metabolism via experimental model of myocardial ischemia fibrosis. The model of myocardial ischemia fibrosis was made for the wistar rats induced with 15 mg/kg isoproterenol（Iso） subcutaneous injection. In experiment l, Iso effective model drug of myocardial ischemia fibrosis at present was administrated to the rats with myocardial ischemia fibrosis and 2, 4, 6, 12, 24, 48 and 72 h, 7 and 21 d later, the changes of adenosine content in rat myocardial tissue and hydroxyproline in blood serum were compared. In experiment 2, SF was administrated to the rats with myocardial ischemia fibrosis and 21 d later, the effect of SF on benazepril as reference drug curing myocardial ischemia fibrosis was evaluated by measuring the changes of adenosine in rat myocardial tissue and hydroxyproline content in blood serum. In the model group, there was a remarkable increase in hydroxyproline content and a decrease in adenosine content of myocardial tissue in experiment 1; there was a remarkable decrease in hydroxyproline in blood serum and a increase in adenosine content in myocardial tissue, which were recovered gradually to control in experiment 2（P〈0.05）. The results of experiment 1 show that with the increasing of pathological change degree, the rat adenosine content reduced gradually and arrived at the lowest value three weeks later（P〈0.05）; the hydroxyproline content was obviously higher compared with that of control group（P〈0.05）. The results of experiment 2 show that rat adenosine content in myocardial tissue and hydroxyproline content in blood serum were recovered gradually to normal level after injection SF. The effect of SF against myocardial ischemia fibrosis in preventive group is better than that of improving the myocardial ischemia fibrosis drug. Meanwhile, hinting HPLC is a good method to measure the adenosine content.

Upregulation of miR-29b contributes to the anti-fibrotic effect of macrophage migration inhibitory factor in diabetic myocardial fibrosis

Background Macrophage migration inhibitory factor （MIF） possesses proinflammatory function when secreted from the cells, and it also exhibits antioxidant properties based on its intrinsic oxidoreductase activity. However, the role of MIF in cardiac fibrosis is not well known. In the present study, the effect of MIF on fibrosis-associated gene expression and the underlying mechanism were examined. Methods The collagen content in mouse myocardium was detected by Masson staining. Expressions of MIF and fibrosis-associated Collal, Col3al and α-SMA in mouse myocardium or mouse cardiac fibroblasts were detected by quantitative real-time PCR and Western blot assay, respectively. Mature miR-29b expressions in mouse myocardium and cardiac fibroblasts were determined by real-time PCR. Smad3 activation in MIF-treated cardiac fibroblasts was also detected by Western blot assay. Results Compared with the db/m control mice, the collagen content was significantly increased in the myocardium of diabetic db/db mice. MIF was up-regulated, but miR-29b was down-regulated in the diabetic myocardium. Quantitative real-time PCR and Western blot assay showed that MIF could inhibit fibrosis-associated Collal, Col3al and α-SMA expressions in mouse cardiac fibroblasts. Smad3 activation was inhibited, but miR-29b was up-regulated in MIF-treated cardiac fibroblasts. Enforced expression of miR-29b significantly suppressed Collal, Col3al, and oL-SMA mRNA and lprotein expressions in cardiac fibroblasts. Conclusions MIF possesses the anti-fibrosis activity through inhibiting Smad3 activation and through up-regulating miR-29b expression, and miR-29b can inhibit fibrosis-associated Collal, Col3al and α-SMA expressions in cardiac fibroblasts.

Effect of carvedilol on attenuating the acute myocardial infarction-induced myocardial fibrosis in rats

Carvedilol, nonselective β-adrenoreceptor antagonist, was showed protective effects against acute myocardial infarction （AMI）-induced myocardial injury, however, the mechanisms underlying the anti- fibrosis effect of carvedilol has not been well known. The aim of the present study was to investigate the potential mechanism for the anti-fibrosis effect of carvedilol against AMI-induced myocardial fibrosis in rats. Methods Male SD rats were randomized into the sham group, LAD surgery-AMI model group, AMI plus low dose of carvedilol treatment group （1 mg/kg per day, CAR-L）, AMI plus medium dose of carvedilol treatment group （5 mg/kg per day, CAR-M） and AMI plus high dose of carvedilol treatment group （10 mg/kg per day, CAR-H）. The passage 3 neonatal SD rat cardiac fibroblasts were used for hypoxia/normoxia （2 h/4 h） treatment in the presence of carvedilol （0, 1, 2 and 4 μM）. Results Cardiac remodeling and impaired heart function were observed after 14-week LAD surgery treatment, however, and the cardiac remodeling and decreased ejection fraction （EF%） and fractional shortening （FS%） were efficiently rescued in the CAR-M and CAR-H groups. The up-regulated expressions of Collal, Col3al and tx-SMA at mRNA and protein levels were significantly reduced in the CAR-M and CAR-H groups. The in vitro study showed that Collal, Col3al and ot- SMA expressions at both mRNA and protein levels were down-regulated by carvedilol in rat cardiac fibroblasts in a dose-dependent manner. Smad3 inhibitors, SIS-3 and naringenin, could efficiently decrease Collal, Col3al and α-SMA expressions in rat cardiac fibroblasts. Smad3 was shown significantly inactivated in carvedilol-treated rat cardiac fibroblasts. Conclusion Carvedilol negatively regulates Smad3 signal pathway and inhibits extracellular matrix related Collal, Col3al and α-SMA expressions, contributing to the anti-fibrosis effect of carvedilol against AMI-induced myocardial fibrosis in rats.

Myocardial fibrosis detection in arrhythmogenic right ventricular dysplasia/cardiomyopathy by 3. 0T magnetic resonance imaging

Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is characterized by fibro-fatty replacement of the right ventricle.However,the feasibility and significance of myocardial fibrosis detec-ted by delayed enhancement (DE) using 3.0T magnetic resonance imaging (MRI) in.ARVD /C is seldomly studied.Methods Twenty-seven consecutive patients were prospectively evaluated for ARVD /C.Magnetic reso-nance imaging was performed on a 3.0T scanner.Ten minutes after intravenous administration of 0.2 mmol /kg of gadodiamide,DE-MRI was obtained.Diagnosis of ARVD /C was based upon the Task Force criteria and in-cluded MRI findings.Results Seventeen(59% ) of 27 patients met the Task Force criteria for ARVD /C.Right ven-tricle DE was found in all (100% ) ARVD /C patients compared with none (0%) of the 10 patients without ARVD /C (P <0.001) .Additional left ventricular DE was found in 8/17 ARVD/C patients while without left ventricular mor-phological and functional abnormalities detected by echocardiography or MRI.Conclusions DE using 3.0T MRI could effectively detect myocardial fibrosis in the right and left ventricular myocardium in ARVD /C patients.Detection of myocardial fibrosis may have an important clinical significance in ARVD/C diagnosis.Histological left ventricle in-volvement may be easily missed by echocardiography.