Collagen Fibers In Myocardium Research Articles

Phloridzin prevents diabetic cardiomyopathy by reducing inflammation and oxidative stress

Oxidative stress and inflammation significantly contribute to the pathogenesis of diabetic cardiomyopathy (DCM). Persistent inflammatory stimuli drive the progression of myocardial fibrosis and impaired cardiac function. Phloridzin (Phl), a natural compound, demonstrates both anti-inflammatory and antioxidant properties. Nevertheless, its therapeutic potential and underlying mechanisms in DCM remain unclear. This study aimed to elucidate the mechanisms through which Phl inhibited myocardial fibrosis and exerted its antioxidative effects. The impact of Phl on DCM was evaluated using a high-fat/high-sugar diet combined with streptozotocin to induce an animal model and an in vitro H9C2 cell model stimulated by high glucose (HG). Untargeted metabolomics identified potential mechanisms underlying myocardial fibrosis. Phl treatment significantly enhanced left ventricular ejection fraction (EF%) and shortening fraction (FS%), while reducing myocardial injury markers, such as lactate dehydrogenase and creatine phosphokinase-MB, and suppressing myocardial collagen fiber accumulation. Simultaneously, Phl attenuated myocardial inflammation via inhibition of MyD88/NF-κB signaling, modulated the Nrf2/GPX4 axis to counter oxidative stress, and mitigated ferroptosis. In vitro, Phl inhibited high glucose-induced myocardial hypertrophy and fibrosis in H9C2 cells, while also repressing NF-κB activation in cardiomyocytes. Metabolomic profiling revealed that Phl ameliorated DCM through modulation of glycerophospholipid metabolic pathways, linking these metabolic shifts to enhanced antioxidant capacity, thereby reflecting its ability to reduce oxidative stress in the myocardium. Collectively, Phl provides cardioprotective effects by alleviating inflammation and oxidative damage.

Effect of Linggui Zhugan Decoction on myocardial fibrosis and Lats1/Yap signaling pathway in mice after myocardial infraction

This study aims to investigate the effects of Linggui Zhugan Decoction(LGZGD) on myocardial fibrosis(MF) and the Lats1/Yap signaling pathway in mice after myocardial infarction(MI), exploring its role and mechanism in inhibiting MF. The MI-induced ischemic mouse model was established by left anterior descending coronary artery ligation, followed by continuous intervention for six weeks. Doppler ultrasound imaging-system of small animals was used to detect left ventricular ejection fraction(LVEF), left ventricular fractional shortening(LVFS), left ventricular internal diameter at end-systole(LVIDs), and left ventricular internal diameter at end-diastole(LVIDd). Pathological changes in myocardial tissue were observed by HE and Masson staining. Serum levels of creatine kinase isoenzyme MB(CK-MB) and lactate dehydrogenase(LDH) were detected by using ELISA. Myocardial tissue mRNA levels of Lats1, Yap, and connective tissue growth factor(CTGF) were determined by RT-qPCR. Protein expression of alpha-smooth muscle actin(α-SMA), collagen Ⅰ(Col Ⅰ), collagen Ⅲ(Col Ⅲ), tissue inhibitor of metal protease 1(TIMP1), matrix metallopeptidase 2(MMP2), Yap, p-Yap, and n-Yap was determined by Western blot. Compared with the sham group, the model group showed significantly decreased LVEF and LVFS levels, increased LVIDd and LVIDs levels(P<0.01), disordered arrangement of myocardial cells, partial fracture of myocardial fibers, and massive deposition of collagen fibers. Moreover, serum levels of CK-MB and LDH were significantly increased(P<0.01), while myocardial tissue mRNA levels of Lats1 were significantly decreased(P<0.01), and mRNA levels of Yap and CTGF were significantly increased(P<0.01). Protein expression of α-SMA, Col Ⅰ, Col Ⅲ, MMP2, Yap, and n-Yap was significantly increased(P<0.01), while protein expression of Lats1, TIMP1, p-Yap, and the ratio of p-Yap/Yap were significantly decreased(P<0.01). Compared with the model group, after intervention with LGZGD(9.36 g·kg~(-1)), mice showed significantly increased LVEF and LVFS levels, decreased LVIDd and LVIDs levels(P<0.01), more orderly arrangement of myocardial cells, significantly reduced myocardial fiber fracture and collagen fiber deposition. Serum levels of CK-MB and LDH were significantly decreased(P<0.01), while myocardial tissue mRNA levels of Lats1 were significantly increased(P<0.01), and mRNA levels of Yap and CTGF were significantly decreased(P<0.01). Protein expression of α-SMA, Col Ⅰ, Col Ⅲ, MMP2, Yap, and n-Yap was significantly decreased(P<0.01), while protein expression of Lats1, TIMP1, p-Yap, and the ratio of p-Yap/Yap were significantly increased(P<0.01). LGZGD can inhibit MF in mice after MI and improve mouse cardiac function, which is closely related to the activation of the Lats1/Yap signaling pathway.

Quercetin Ameliorates Myocardial Injury in Diabetic Rats by Regulating Autophagy and Apoptosis through AMPK/mTOR Signaling Pathway.

A high-glucose environment is involved in the progression of diabetes mellitus (DM). This study aims to explore the regulatory effects of quercetin (QUE) on autophagy and apoptosis after myocardial injury in rats with DM. The type 2 DM rat models were constructed using low-dose streptozotocin (STZ) treatment combined with a high-carbohydrate (HC) diet in vivo. Compared with the control group, the body weight was decreased, whereas blood pressure, blood glucose, and the LVW/BW ratio were increased in the diabetic group. The results showed that the myocardial fibers were disordered in the diabetic group. Moreover, we found that the myocardial collagen fibers, PAS-positive cells, and apoptosis were increased, whereas the mitochondrial structure was destroyed and autophagic vacuoles were significantly reduced in the diabetic group compared with the control group. The expression levels of autophagy-related proteins LC3 and Beclin1 were decreased, whereas the expression levels of P62, Caspae-3, and Bax/Bcl-2 were increased in the diabetic group in vitro and in vivo. Moreover, QUE treatment alleviated the cellular oxidative stress reaction under high-glucose environments. The results of immunoprecipitation (IP) showed that the autophagy protein Beclin1 was bound to Bcl-2, and the binding capacity increased in the HG group, whereas it decreased after QUE treatment, suggesting that QUE inhibited the binding capacity between Beclin1 and Bcl-2, thus leading to the preservation of Beclin1-induced autophagy. In addition, the blood pressure, blood glucose, and cardiac function of rats were improved following QUE treatment. In conclusion, QUE suppressed diabetic myocardial injury and ameliorated cardiac function by regulating myocardial autophagy and inhibition of apoptosis in diabetes through the AMPK/mTOR signaling pathway.

Mechanism of Shexiang Tongxin Dropping Pills in treating diabetic cardiomyopathy based on network pharmacology and animal experiments

This study aimed to explore the mechanism of Shexiang Tongxin Dropping Pills(STDP) in treating diabetic cardiomyopathy(DCM) based on network pharmacology, molecular docking, and animal experiments. BATMAN, TCMSP, and GeneCards were searched for the active ingredients and targets of STDP against DCM. STRING and Cytoscape were used to build the protein-protein interaction(PPI) network and "drug-active ingredient-target" network. Gene Ontology(GO) functional annotation and Kyoto Encyclopedia of Genes and Genomes(KEGG) enrichment analysis of the targets were carried out based on DAVID. The molecular docking of key receptor proteins with corresponding active ingredients was performed using AutoDock Vina. The rat model of DCM was established by a high-fat diet combined with intraperitoneal injection of streptozotocin. Rats were assigned into control, model, low-(20 mg·kg~(-1)) and high-dose(40 mg·kg~(-1)) STDP, and metformin(200 mg·kg~(-1)) groups. After 8 weeks of continuous administration, the cardiac function, myocardial pathological changes, and myocardial collagen fiber deposition of rats in each group were detected by echocardiography, hematoxylin-eosin(HE) staining, and Sirius red staining, respectively. The myocardial hypertrophy was detected by WGA staining. The expression levels of p38 mitogen-activated protein kinase(p38), phosphorylation-p38(p-p38), c-Jun N-terminal kinase(JNK), phosphorylation-JNK(p-JNK), caspase-3, and C-caspase-3 in the myocardial tissue of rats in each group were measured by Western blot. The network pharmacology predicted 199 active ingredients and 1 655 targets of STDP and 463 targets of DCM. One hundred and thirty-four potential targets of STDP for treating DCM were obtained, and the AGE-RAGE signaling pathway in diabetic complications was screened out. Molecular docking results showed that miltirone, dehydromiltirone, and tryptanthrin had strong binding affinity with RAGE. The results of animal experiments confirmed that STDP effectively protected the cardiac function of DCM rats. Compared with the DCM model group, the STDP groups showed significantly down-regulated protein levels of p-p38, p-JNK, and C-caspase-3. To sum up, STDP may protect the cardiac function of DCM rats by regulating the AGE-RAGE signaling pathway.

Astragalus (Astragalus mongholicus) Improves Ventricular Remodeling via ESR1 Downregulation RhoA/ROCK Pathway.

Astragalus (Astragalus mongholicus) alleviates myocardial remodeling caused by hypertension. However, the detailed molecular mechanism is unclear. This study aims to investigate the effect of Astragalus on ventricular remodeling in ovariectomized spontaneous hypertensive rats (OVX-SHR).Female SHR/NCrl rats were subjected to bilateral ovariectomy to establish the OVX-SHR model and treated with Astragalus extract by gavage. The hemodynamics and cardiac function parameters were measured. HE and Masson staining were used to detect the pathological structure of myocardial remodeling and observe the hyperplasia of myocardial collagen fibers. The immunohistochemistry tested the level of α-SMA. The expression levels of inflammatory cytokines, IκB, p65, Cleaved-Caspase3, RhoA, and ROCK1/2 were detected using Western blot. The method of qRT-PCR measured the expression of matrix metalloproteinase (MMP-2 and MMP-9).Hemodynamic and cardiac function parameters were significantly improved after a high dose of Astragalus extract and Valsartan treatment. The myocardial integrity of the model group was significantly reduced, arranged loosely, and disordered, while the expression of α-SMA was increased. However, Astragalus extract and Valsartan treatments significantly reduced the pathological damage and α-SMA. The levels of TNF-α, IL-1β, IL-6, TGF-β, MMP-2, and MMP-9 in the model group were increased but decreased after Astragalus extract treatment. Adding an ESR1 inhibitor attenuated the improvement effect of Astragalus extract on myocardial remodeling and restored the expression of RhoA and ROCK1/2.Astragalus extract attenuates the cardiac damage in OVX-SHR by downregulating the RhoA/ROCK pathway through ESR1.

Effects of terbuthylazine on myocardial oxidative stress and ferroptosis via Nrf2/HO-1 signaling pathway in broilers

Terbuthylazine (TBA) is one of the most commonly used and effective herbicides. However, due to its affinity for soil organic matter and water solubility, TBA can lead to biological health concerns. This study exposed broilers to TBA (0 mg/kg bw, 0.4 mg/kg bw, 4 mg/kg bw) for 28 days. The results showed significant pathological damage in broiler myocardial tissue, such as widening of the interstitial space, rupture of muscle fibers, and deposition of myocardial collagen fibers. In addition, Under the 0.4 mg/kg bw TBA exposure, myocardial oxidative stress was observed in broilers, which was accompanied by the activation of Nrf2/HO-1 pathway and the increased protein and mRNA levels of NQO1, NOX2 and SOD2 antioxidant enzymes. However, Nrf2/HO-1 protein and mRNA levels were reversed at 4 mg/kg bw TBA exposure. Meanwhile, the Nrf2/HO-1 mediated antioxidant defense was impaired. In contrast with the low dose, the protein and gene expression levels of NQO1, NOX2, and SOD2 were reduced in 4 mg/kg bw TBA group. The expression of GPX4 and SLC7A11 was significantly downregulated at both protein and mRNA levels. Beyond that, ACSL4 expression was significantly up-regulated, and the protein result was consistent with the mRNA expression, demonstrating the occurrence of ferroptosis. In general, TBA exposure activated the Nrf2/HO-1 pathway, resulting in ferroptosis. This study links ferroptosis to the Nrf2/HO-1 pathway, providing new insights into the potential role of TBA in myocardial toxicity.

Exploring the effects and mechanisms of Guizhigancao Decoction on heart failure using an integrated approach based on experimental support and network pharmacology strategy.

HF (Heart Failure) is the leading cause of mortality and is a significant clinical problem affecting millions of patients worldwide. To date, the mechanisms of HF remain largely elusive. The effective treatments contributing to HF remain incompletely understood. Therefore, the development of an effective strategy for HF is urgently needed. In the present study, we devoted to investigating the effective treatments and sought to systematically decipher the related molecular mechanisms of Guizhigancao Decoction (GZGCD, Cinnamomum cassia Presl and Glycyrrhizae Radix Et Rhizoma Praeparata Cum Melle) for treating HF. We examined the therapeutic effect of GZGCD on HF invivo. An integrative approach combining biomarker examination, echocardiography, myocardial fibrosis and cardiac apoptosis condition using Masson and TUNEL staining was performed to assess the efficacy of GZGCD against HF. Subsequently, comprehensive network pharmacology analyses were performed to explore the mechanisms involved in GZGCD therapeutic effects on HF. The results showed that GZGCD could reverse cardiac function in rats with HF by reducing NT-proBNP, increasing EF, decreasing LVESV, LVEDV, LVIDs, LVIDd, increasing running time, and ameliorate myocardial collagen fiber hyperplasia and cardiomyocyte apoptosis. We showed that GZGCD might contribute to HF treatment via oxidative related pathways through bioinformatics. Eventually, promising compound quercetin in GZGCD for HF therapeutics was proposed in database-based analysis. Collectively, our findings indicate that GZGCD has a treatment effect on HF. We proposed that GZGCD might contribute HF treatment via oxidative response-related pathways.

Effect of blood flow-restricted resistance training on myocardial fibrosis in early spontaneously hypertensive rats.

The purpose of this study was to explore the effect of blood flow-restricted resistance training on myocardial fibrosis in early spontaneously hypertensive rats (SHRs). Four-week-old male Wistar-Kyoto rats and SHRs were randomly divided into the following groups: normal group (WKY), SHR control (SHR-SED) group, high-intensity resistance training (HIRT) group, low- and medium-intensity resistance training (LMIRT) group, and blood flow-restricted low- and medium-resistance training (BFRT) group. Body weight, hemodynamics, cardiac function, myocardial morphology and fibrosis, and the expression levels of transforming growth factor-beta1-Smad (TGFβ-1-Smad) pathway-related proteins in the myocardium were assessed. (1) BFRT lowered blood pressure significantly, decreased left ventricular wall thickness, and improved cardiac function. At the same time, BFRT was superior to traditional resistance training in lowering diastolic blood pressure, and was superior to HIRT in improving left ventricular compliance, reducing heart rate, and reducing left ventricular posterior wall and left ventricular mass (P < 0.05). (2) BFRT decreased collagen I and collagen fiber area in the myocardium, increased the collagen III area, and decreased the collagen I/III ratio (P < 0.05). BFRT produced a better proportion of myocardial collagen fibers than did traditional resistance training (P < 0.05). (3) In the myocardium of the BFRT group compared to the traditional resistance training group, the expression of TGFβ-1, Smad2/3/4, p-Smad2/3, CTGF, and TIMP1 was significantly downregulated, MMP2 and TIMP2 were significantly upregulated, the MMP/TIMP ratio significantly increased, and TGFβ-1 expression significantly decreased (P < 0.05). BFRT inhibited the TGFβ-1-Smad pathway in the myocardium, downregulated the expression of CTGF, and regulated the balance between MMPs and TIMPs, thereby reducing myocardial fibrosis in SHR, and improving cardiac morphology and function. BFRT also lowered blood pressure, and achieved an effect of early prevention and treatment of hypertension. At the same time, BFRT was superior to traditional resistance training in reducing diastolic blood pressure and adjusting the proportion of myocardial collagen fibers.

Shexiang Tongxin Dropping Pills improve cardiac function in type 2 diabetic rats by promoting angiogenesis

This study aims to investigate the effect of Shexiang Tongxin Dropping Pills(STDP) on angiogenesis in type 2 diabetic rats. Thirty-two healthy male SD rats were randomized into a control group(n=6) and a type 2 diabetes mellitus(T2 D) group(n=26). The T2 DM rat model was established with a high-fat diet combined with intraperitoneal injection of streptozotocin(STZ). The model rats were randomized into a model group, a metformin group(200 mg·kg~(-1)·d~(-1)), a high-dose STDP group(40 mg·kg~(-1)·d~(-1)), and a low-dose STDP group(20 mg·kg~(-1)·d~(-1)). The corresponding agents were administered continuously for 8 weeks. The cardiac function indexes were detected by ultrasound at the experiment endpoint, and the myocardial pathological changes were observed via hematoxylin-eosin(HE) staining. The myocardial collagen fiber deposition was detected by sirius red staining, the myocardial microvascular density by immunohistochemistry, and the myocardial hypertrophy by immunofluorescence assay. Western blot was employed to measure the protein levels of vascular endothelial growth factor(VEGF), phosphorylated vascular endothelial growth factor receptor 2(p-VEGFR2), angiogenin-1(Ang1), and TEK tyrosine kinase endothelial(Tie2) in the myocardial tissue. Compared with the model group, STDP improved the left ventricular ejection fraction(EF) and fractional shortening(FS)(P&lt;0.05), alleivated the arrangement disorder of myocardial cells and local myocardial fiber rupture. Sirius red staining showed that STDP, especially the high-dose group(P&lt;0.01), repaired the deposition of myocardial collagen fibers in the model group. The results of immunohistochemistry showed that the cluster of differentiation 31(CD31) expression in myocardial tissue of the STDP groups was higher than that of the model group(P&lt;0.01). The immunofluorescence results showed that STDP mitigated the hypertrophy of myocardial cells(P&lt;0.01). Furthermore, STDP up-regulated the protein levels of VEGF, p-VEGFR2, Angl, and Tie2 compared with the model group(P&lt;0.01). In conclusion, STDP can effectively promote angiogenesis and improve cardiac function in type 2 diabetic rats by up-regulating the expression of VEGF, p-VEGFR2, Ang1, and Tie2.

Effect of epithelial-mesenchymal transition on cardiac fibrosis induced by oil mist particulate matter

Objective: To investigate the effects of oil-mist particulate matter (OMPM) on cardiac tissue structure fibrosis in rats and the role of epithelial-mesenchymal transition (EMT). Methods: Six-week-old Wistar rats (half male and half female) were randomly divided into 3 groups: control group (without OMPM exposure), low-dose exposure group (50 mg/m3) and high-dose exposure group (100 mg/m3), 18 rats in each group, with 6.5 hours per day of dynamic inhalation exposure. After 42 days of continuous exposure, cardiac tissues were collected for morphological observation; Western blot was used to detect fibrosis markers collagen I and collagen III levels, epithelial marker E-cadherin levels, interstitial markers N-cadherin, fibronectin, vimentin, alpha-smooth muscle actin (α-SMA) levels, and EMT transcription factor Twist protein levels; Real-time polymerase chain reaction (RT-qPCR) was used to detect collagen I and collagen III mRNA levels. Results: After OMPM exposure, myocardial cell edema and collagen fiber deposition were increased gradually with increasing exposure dose. Western blot results showed that compared with the control group, the expression levels of collagen I, collagen III, N-Cadherin, fibronectin, vimentin, α-SMA, and Twist protein were increased significantly in the low-dose exposure group and the high-dose exposure group (P＜0.01), and protein expression levels were higher in the high-dose exposure group than those in the low-dose exposure group (P＜0.01). In contrast, E-Cadherin protein expression levels were decreased significantly, and lower in the high-dose exposure group (P＜0.01). RT-qPCR results showed that compared with the control group, collagen I and collagen III mRNA levels were increased significantly in the low-dose exposure group and the high-dose exposure group (P＜0.01), and were increased with increasing exposure dose. (P＜0.01). Conclusion: OMPM may induce cardiac fibrosis in rats by promoting EMT process.

Protective effect of Esculetin on myocardial injury induced by doxorubicin

Objective: To study the protective effect of Esculetin on myocardial injury induced by doxorubicin and explore the mechanism of doxorubicin on myocardial injury in rats. Methods: Doxorubicin(2.5mg/kg) was injected intraperitoneally every other day for 6 times to establish a rat model of myocardial injury. The effects of different doses of Esculetin (10mg/kg &amp; 20mg/kg) on serum myocardial enzymes and myocardial tissue were observed. Results: Doxorubicin significantly increased serum myocardial enzymes and the content of myocardial interstitial collagen fibers in mice. Different doses of Esculetin could reduce myocardial injury in a dose-dependent manner. Conclusion: Esculetin has a protective effect on myocardial injury induced by doxorubicin.

Relaxin-3 Ameliorates Diabetic Cardiomyopathy by Inhibiting Endoplasmic Reticulum Stress

Background This study is aimed at investigating whether relaxin-3 exhibits protective effects against cardiomyopathy in diabetic rats by suppressing ERS. Methods Eighty male SD rats were randomly divided into two groups: controls (n = 20) and diabetes (n = 60). The streptozotocin-treated rats were randomly divided into three groups: diabetic group (DM), low-dose relaxin-3 group (0.2 μg/kg/d), and high-dose relaxin-3 group (2 μg/kg/d). The myocardial tissues and collagen fiber were observed by hematoxylin and eosin (H&E) and Masson staining. Serum brain natriuretic peptide (BNP), troponin (TNI), myoglobin, interleukin (IL-17), interleukin (IL)-1α, and tumor necrosis factor (TNF)-α were determined by ELISA. The protein expression of glucose regulatory protein 78 (GRP78) and C/EBP homologous protein (CHOP) in the heart tissue of each group was detected by Western blot analysis. Results (1) HE and Masson staining indicated that relaxin-3 could attenuate myocardial lesions and myocardial collagen volume fraction. (2) BNP, TnI, and myoglobin in the DM group at four and eight weeks were significantly higher than in the controls (P < 0.01). The relaxin-3-treated groups showed significantly reduced serum BNP, TnI, and myoglobin levels compared with the DM group (P < 0.05). (3) IL-17, IL-1α, and TNF-α levels in the DM rats at 4 weeks were higher than in the controls (P < 0.05). Low or high dose of relaxin-3-treated groups showed reduced serum IL-17 and TNF-α levels compared with the DM group at four and eight weeks (P < 0.05). (4) CHOP and GRP78 protein expression was increased in the DM group at four and eight weeks compared with the controls (P < 0.01), and small and large doses of relaxin-3 significantly reduced GRP78 and CHOP protein expression. Conclusions Exogenous relaxin-3 ameliorates diabetic cardiomyopathy by inhibiting ERS in diabetic rats.

Adverse cardiovascular effects of antiretrovirals in female mice during gestation

Objective: To evaluate the effects of antiretrovirals on cardiovascular function and some biochemical indexes in gestational female rats. Methods: Nineteen 9-week-old female and six 10-week-old male SD rats were divided into normal control group (CON) and highly active antiretroviral therapy group (HARRT), 9/10 female rats and 3 male rats were combined into one cage, totally 2 cages. Female rats in CON group were intragastrically given with normal saline (NS, 10 ml/kg) every morning and evening, while female rats in HARRT group were treated with equal volume antiretrovirals (AZT 31.25 mg/kg + 3TC 15.63 mg/kg + LPV/r (41.67/10.42) mg/kg) for 3 months. The body weight and survival rate of female rats were recorded. Echocardiography and multichannel physiological recorder were used to detect arterial blood pressure and cardiac hemodynamic parameters. The levels of blood glucose, blood lipids, myocardial enzymes and liver enzymes were detected by corresponding kits. Myocardial collagen fibers were observed by Masson staining and the ultrastructure of myocardial cells were observed by transmission electron microscopy. Results: All female rats in CON group survived (9/9), while only 6 rats in HARRT group survived (6/10). Compared with CON group, the body weight of female rats in HAART group was decreased significantly(P＜0.01); the levels of left ventricular end diastolic diameter (LVDd), interventricular septal thickness (IVST), thickness of left ventricular posterior wall (LVPWT) , left atrial diameter (LAD) and arterial diastolic pressure were increased significantly (P＜0.05); the level of LVP+dP/dtmax was decreased (P＜0.01). The levels of triglyceride, creatine kinase, and glutamic oxaloacetic transaminase were decreased (P＜0.05 or P＜0.01), while the level of glucose was increased (P＜0.05). The collagen fibers were increased in myocardial tissue, and ultrastructure of myocardial cells was abnormal. Conclusion: Antiretrovirals during gestation can cause cardiovascular diseases in female rats.

Abstract P2098: A Novel Measure Of Myocardial Collagen Structure Using Ultrasonic Backscatter

Aging and disease are associated with dysregulation of collagen deposition and collagen degradation and crosslinking. These modifications in collagen structure are key determinants of cardiac integrity and function, making it advantageous to monitor collagen’s state throughout disease. Although myocardial fibrosis often occurs alongside both cardiac and systemic disease, monitoring myocardial collagen typically requires expensive, invasive, and/or contraindicated methods. However, collagen content has been correlated to ultrasonic backscatter, a low-cost, non-invasive index. Preliminary studies in our lab suggested collagen also dominates the anisotropy of backscatter(variation in the brightness) in a left ventricular short-axis ultrasound. The purpose of the present study was to determine a relationship between myocardial collagen structure and anisotropy of ultrasonic backscatter while using collagenase to degrade myocardial collagen networks. Hearts were excised from Sprague Dawley rats and perfused with a collagenase-containing solution for either 10 (n=7) or 30 minutes (n=7) or control solution for 30 minutes (control n=8). Serial ultrasound images were acquired throughout collagenase digestion and ultrasonic backscatter was assessed where the collagen is primarily aligned perpendicular to the angle of insonification (bright on ultrasound image), and where collagen is primarily aligned parallel to the angle of insonification (darker on image). Our data suggested that collagenase digestion reduced backscatter anisotropy within the myocardium (p&lt;0.001) with the lateral and septal walls (collagen parallel to ultrasound) showing the greatest change in backscatter intensity. Histology (Trichrome staining) and biochemistry (hydroxyproline assay) suggests that collagen remains present but its crosslinking is altered within 10 minutes (p&lt;0.047). These data suggest that myocardial collagen fiber orientation and crosslinking of collagen correlates with the anisotropy of ultrasonic backscatter. Thus, anisotropy of ultrasonic backscatter could potentially be used to assess collagen crosslinking and deposition.

Combined use of systemic quercetin, glutamine and alpha-tocopherol attenuates myocardial fibrosis in diabetic rats

This study aimed to analyze the effects of the quercetin (100 mg/kg), 1% glutamine and 1% α-tocopherol antioxidants in the myocardium of rats with streptozotocin-induced diabetes mellitus. Twenty male rats were subdivided into four groups (n = 5): N (normoglycemic); D (diabetic); NT (normoglycemic treated with antioxidants); and DT (diabetic treated with antioxidants) treated for 60 days. Clinical parameters, oxidative stress markers, inflammatory cytokines, myocardial collagen fibers and immunoexpression of superoxide dismutase 1 (SOD-1), glutathione peroxidase-1 (GPx-1), interleukin-1β (IL-1-β), transforming growth factor-beta (TGF-β), and fibroblast growth factor-2 (FGF-2) were evaluated. Results showed reduced body weight, hyperphagia, polydipsia and hyperglycemic state in groups D and DT. The levels of glutathione (GSH) were higher in NT and DT compared to N (p < 0.01) and D (p < 0.001) groups, respectively. Greater GSH levels were found in DT when compared to N animals (p < 0.001). In DT, there was an increase in IL-10 in relation to N, D and NT (p < 0.05), while GPx-1 expression was similar to N and lower compared to D (p < 0.001). TGF-β expression in DT was greater than N (p < 0.001) group, whereas FGF-2 in DT was higher than in the other groups (p < 0.001). A significant reduction in collagen fibers (type I) was found in DT compared to D (p < 0.05). The associated administration of quercetin, glutamine and α-tocopherol increased the levels of circulating interleukin-10 (IL-10) and GSH, and reduced the number of type I collagen fibers. Combined use of systemic quercetin, glutamine and alpha-tocopherol attenuates myocardial fibrosis in diabetic rats.

Exogenous Hydrogen Sulfide Ameliorates Diabetic Myocardial Fibrosis by Inhibiting Cell Aging Through SIRT6/AMPK Autophagy.

Stress aging of myocardial cells participates in the mechanism of myocardial fibrosis (MF). Previous studies have shown that hydrogen sulfide (H2S) can improve MF, however the specific internal mechanism remains still unclear. Therefore, this study aims to explore whether H2S can improve myocardial cell aging induced by high glucose and myocardial fibrosis in diabetic rats by activating autophagy through SIRT6/AMPK. We observed that HG (high glucose, 33 mM) induced down-regulation of endogenous H2S-producing enzyme CSE protein expression, increased cell senescence, down-regulation of autophagy-related proteins Beclin1, Atg5, Atg12, Atg16L1, and inhibition of SIRT6/AMPK signaling pathway in H9c2 cardiomyocytes. H2S (NaHS: 400 μM) could up-regulate CSE protein expression, inhibit cell senescence, activate autophagy and SIRT6/AMPK signaling pathway. On the contrary, no above phenomena was achieved upon addition of CSE inhibitor PAG (dl-propargylglycine: mmol/L). In order to further elucidate the relationship between H2S and SIRT6/AMPK signaling pathway, dorsomorphin dihydrochloride (Dor), an inhibitor of AMPK signaling pathway, was added to observe the reversal of H2S’s inhibitory effect on myocardial cell aging. At the same, streptozotocin (STZ; 40 mg/kg) was injected intraperitoneally to build an animal model of diabetic SD rats. The results showed that myocardial collagen fibers were significantly deposited, myocardial tissue senescent cells were significantly increased and the expression of CSE protein was down-regulated, while SIRT6/AMPK signaling pathway and cell autophagy were significantly inhibited. H2S-treated (NaHS; 56 μmol/kg) could significantly reverse the above phenomenon. In conclusion, these findings suggest that exogenous H2S can inhibit myocardial cell senescence and improve diabetic myocardial fibrosis by activating CSE and autophagy through SIRT6/AMPK signaling pathway.

LncRNA ROR facilitates myocardial fibrosis in rats with viral myocarditis through regulating C-Myc expression.

The aim of this study was to explore the effect of long non-coding ribonucleic acid (lncRNA) ROR on myocardial fibrosis in rats with viral myocarditis by regulating c-myc expression. A total of 120 healthy male rats were randomly divided into three groups, including: blank control group (group N, healthy rats, n=40), model control group (group M, viral myocarditis, n=40), and group P (lncRNA ROR + viral myocarditis, n=40). At 5, 10, and 15 d after modeling, the rats were sacrificed. Meanwhile, the left ventricular mass index (LVMI), the left ventricular weight/tibial length (LVW/TL) and the heart mass index (HMI) were measured, respectively. The myocardial tissues of rats were observed via staining. The protein and mRNA expressions of the transforming growth factor-β (TGF-β) and c-myc in myocardial tissues were detected via Western blotting and quantitative Real Time-Polymerase Chain Reaction (qRT-PCR), respectively. Moreover, the level of the serum interleukin-6 (IL-6) was detected via enzyme-linked immunosorbent assay (ELISA). Compared with group N, HMI, LVMI, and LVW/TL in group M significantly increased at each time point (p<0.01). Meanwhile, they were remarkably elevated at each time point in group P when compared with those in group M (p<0.01). According to the results of hematoxylin-eosin staining (HE) staining, the myocardial fibers were normal and orderly arranged in group N. Meanwhile, no inflammatory cells were observed in group N. In group M, the proliferation of a large number of inflammatory cells was observed, and the myocardial cells were disorderly arranged and became enlarged. In group P, the myocardial fibrosis was significantly severer than that of the other two groups (p<0.05). The results of the Masson staining revealed that there was significantly less accumulation of collagen fibers in myocardium in group N. There was a little accumulation of collagen fibers in the myocardium and fibrosis declined in group M. The myocardial fibrosis in group P remarkably increased when compared with group M (p<0.05). According to the results of the Western blotting, the protein expressions of c-myc and TGF-β were significantly up-regulated in group P, compared with those in group M and N (p<0.05). However, they were remarkably higher in group M than in group N (p<0.05). QRT-PCR showed that the relative messenger ribonucleic acid (mRNA) expressions of c-myc and TGF-β were remarkably up-regulated in group P when compared with those in group M and N, showing statistically significant differences (p<0.05). Moreover, they were significantly higher in group M than those in group N (p<0.05). Besides, the expression level of serum IL-6 remained highest in group P (p<0.01). LncRNA ROR up-regulates the expression of c-myc and increases the level of serum IL-6, thereby facilitating the proliferation and differentiation of cardiac fibroblasts.

Morphological Changes of Collagen Fibers in Myocardium of Rats under Different Exercise Loads Based on Three-Dimensional Simulation Technique.

In order to improve the visual analysis ability of the morphological changes of rat liulimyocardial collagen fibers under different exercise loads, a method of extracting the morphological changes of collagen fibers in rat myocardium under different exercise loads based on three-dimensional simulation technique is proposed. The three-dimensional morphological characteristics of the collagen fibers in the original rat myocardium are made by CT scanning technique. Like information collection, a gradient decomposition method is used to filter the three-dimensional morphological features of rat myocardial collagen fibers. The edge contour features of the three-dimensional morphological features of rat myocardial collagen fibers under different motion loads are extracted. The threshold segmentation method is used to carry out the rat myocardial glue under different exercise loads. The segmentation of the regional pixel feature block of the three-dimensional morphological features of the original fiber is segmented into a block vector with high resolution, and the regional reconstruction of the three-dimensional morphological features of the rat myocardial collagen fibers under different motion loads is carried out to realize the high resolution identification and classification of the 3D morphological features of the rat myocardial collagen fibers. The simulation results show that the three-dimensional simulation of the morphological changes of rat myocardial collagen fibers under different exercise loads is better, and the accuracy of feature extraction is higher.

Inhibition of Jiang Tang Shu Xin (JTSX) Recipe in Endoplasmic Reticulum Stress CHOP Pathway and Improving Myocardial Remodeling in SD Diabetic Rats

Objective To explore the therapeutic molecular mechanism of Jiang Tang Shu Xin (JTSX) recipe with“invigorating Qi, nourishing Yin, activating blood circulation and detoxifying” in improving insulin resistance, inhibiting apoptotic bypass of endoplasmic reticulum stress (ERS) CCAAT enhance-binding protein homologous protein (CHOP), improving diabetic myocardial remodeling in SD diabetic rats. Methods SD rats were used to establish diabetes mellitus models, and after modeled successfully, were randomly divided into model group, western medicine group (Gliquidone+ Benazepril), low-dose JTSX group (JTSX1), high-dose JTSX group (JTSX2), and accepted corresponding drugs for 2 months respectively, taking the same batch of rats as normal control. After drugs administration finishing, blood lipid were measured by automatic biochemical analyzer, fasting serum insulin (FINS) and glycosylated hemoglobin (GHb) were measured by enzyme-linked immunosorbent assay (ELISA), insulin resistance index (IRI) was calculated. Masson staining was used to detect the expression of myocardial collagen fibers, immunohistochemistry to test the expression of myocardial nuclear factor-kB (NF-kB), tumor necrosis factor-alpha (TNF-α), TUNEL to check the apoptotic level of myocardial cells, RT-PCR to detect the transcription level of ERS molecules glucose regulated protein 78 (GRP78) and CHOP. Results Compared with the model group, the treatment groups could significantly reduce TG, LDL-C, GHb and IRI (P<0.05), increase FINS and HDL-C (P<0.05), decrease inflammatory factors NF-kB and TNF-α (P<0.05), down-regulate transcription of CHOP and GRP78 (P<0.05), and reduce cardiomyocyte apoptosis index (AI) (P<0.05); compared with the western medicine group, JTSX2 had more significant effect (P<0.05). Conclusion JTSX can inhibit insulin resistance, correct lipid metabolism disorder, restrain ERS-induced inflammatory reaction, suppress ERS-initiated apoptotic bypass of CHOP, and improve myocardial remodeling, with dose-dependent.

Salvanic acid B inhibits myocardial fibrosis through regulating TGF-β1/Smad signaling pathway

ObjectiveSalvanic Acid B (Sal B) was proved to show significant effect against fibrosis and myocardial injury. This study aimed to investigate the protective effects and the mechanisms of Sal B on myocardial fibrosis. MethodsThe mice were randomly assigned to five groups: control group, model group, positive group, low-dose group, high-dose group. Hematoxylin-Eosin (HE) staining and Masson staining were used to assess the myocardial physiological changes and measure the myocardial fibrosis area. Expression of transforming growth factor-beta (TGF-β), drosophila mothers against decapentaplegic (Smad)2, Smad3 and Smad7 were analyzed by immunohistochemistry and real-time PCR. On the other hand, mouse cardiac fibroblasts (CFs) cells were co-treated with 20 ng/mL TGF-β1 and different concentrations of Sal B (5, 10, and 20 ng/mL) for 24 h. The cells morphology changes were assessed under a microscope, and the protein expressions induced by TGF-β1 were detected by Western blot. ResultsCompared with the model group, myocardial collagen fibers decreased obviously with Sal B treatment (p < 0.05). Moreover, the expression of key signal molecules of the TGF-β/Smads signaling pathway, including TGF-β1, Smad2 and Smad3 proteins decreased, while the expression of Smad7 increased in Sal B treatment groups as compared to those of the model group (p < 0.05). On the other hand, results of CFs studies were also consistent with those animals. ConclusionsSal B could inhibit the myocardial fibrosis process through regulating TGF-β/Smads signal transduction pathways.