Project description:OBJECTIVE: To study the genetic regulatory mechanisms in the remote zone of left ventricular (LV) free wall in order to partly explain the more frequent progression to heart failure after acute myocardial infarction (AMI) in diabetic rats. METHODS: 10 weeks after diabetes mellitus (DM) induction with Streptozotocin (STZ), the left anterior descending coronary arteries of uncontrolled diabetic Sprague-Dawley (SD) rats and non-diabetic ones were ligated without reperfusion. Then, the remote zone tissues of LV free wall were taken as samples at day 1, 7, 14, 28, and 56 post AMI. Significant different expression genes were filterd from Affymetrix Genechip U230 2.0 array by GCOS software. Genetic changes post myocardial infarction were classified by hierarchical clustering of 10 gene chips. And then, the differential expressions of 10 selected transcripts identified by the microarray were examined in greater detail by Real Time-PCR. RESULTS: According to hierarchical clustering, we find that the molecular regulatory expression related to cardiac remodeling in the remote zone to myocardial infarction is quite different as time elapses in both diabetic and non-diabetic rats. The gene expression at day 1 and 7 post AMI in both groups is similar, while the genetic changes at day 14 post AMI in diabetic rats and the ones at day 14 and 28 in non-diabetic rats are classified into the same cluster. And then the genetic changes at day 28 and 56 post AMI in diabetic rats and the ones at day 56 in non-diabetic rats are classified into the same cluster. (Figure.1) The patterns of numerous products of genes expression were used in the cluster, including 118 genes, such as leucine-rich PPR-motif containing (IL-6 signaling pathway), procollagen type I, VI, VIII, and XV, fibronectin1, RT1, and TIMP-1, etc. CONCLUSION: The genetic findings in this study might be the possible mechanism that diabetes mellitus can accerate the progression of post-infarction genetic regulatory expression. Experiment Overall Design: All studies were performed with male SD rats (200-220g), aged 8 weeks, which were obtained from laboratorial animal center of Chinese University of Agriculture. DM was induced with a singleintraperitoneal injection of STZ (65 mg/kg in 0.1mmol/L, pH 4.5 sodium citrate buffer) . Age and body weight matched rats that used as non-diabetic controls were injected with the same dose of sodium citrate buffer (0.1mmol/L, pH 4.5). Ultrastructure changes of myocardium were observed 10 weeks after DM induction by TEM. 10 weeks after DM induction,both diabetic and non-diabetic rats were subjected to left anterior descending coronary artery (LADCA) ischemia for 1-56 days without reperfusion. Two-dimensional echocardiography was utilized to obtain LV dimensions and LV percent fractional shortening at baseline, DM 10weeks, and at 1d, 7d, 14d, 28d, 56d after AMI; the remote zone tissues of LV free wall were taken as samples at day 1, 7, 14, 28, and 56 post AMI for gene chip microarray analysis (10 samples from 30 rats); in addition, heart-to-body weight and heart to tibial length ratios and masson's trichrome staining was measured as an index of cardiac hypertrophy and fibrosis at baseline, DM 10weeks, and at 1d, 7d, 14d, 28d, 56d after AMI.

Project description:OBJECTIVE: To study the genetic regulatory mechanisms in the remote zone of left ventricular (LV) free wall in order to partly explain the more frequent progression to heart failure after acute myocardial infarction (AMI) in diabetic rats. METHODS: 10 weeks after diabetes mellitus (DM) induction with Streptozotocin (STZ), the left anterior descending coronary arteries of uncontrolled diabetic Sprague-Dawley (SD) rats and non-diabetic ones were ligated without reperfusion. Then, the remote zone tissues of LV free wall were taken as samples at day 1, 7, 14, 28, and 56 post AMI. Significant different expression genes were filterd from Affymetrix Genechip U230 2.0 array by GCOS software. Genetic changes post myocardial infarction were classified by hierarchical clustering of 10 gene chips. And then, the differential expressions of 10 selected transcripts identified by the microarray were examined in greater detail by Real Time-PCR. RESULTS: According to hierarchical clustering, we find that the molecular regulatory expression related to cardiac remodeling in the remote zone to myocardial infarction is quite different as time elapses in both diabetic and non-diabetic rats. The gene expression at day 1 and 7 post AMI in both groups is similar, while the genetic changes at day 14 post AMI in diabetic rats and the ones at day 14 and 28 in non-diabetic rats are classified into the same cluster. And then the genetic changes at day 28 and 56 post AMI in diabetic rats and the ones at day 56 in non-diabetic rats are classified into the same cluster. (Figure.1) The patterns of numerous products of genes expression were used in the cluster, including 118 genes, such as leucine-rich PPR-motif containing (IL-6 signaling pathway), procollagen type I, VI, VIII, and XV, fibronectin1, RT1, and TIMP-1, etc. CONCLUSION: The genetic findings in this study might be the possible mechanism that diabetes mellitus can accerate the progression of post-infarction genetic regulatory expression.

Project description:Myocardial ischemic preconditioning (IPC) enhances myocardial resilience to ischemic injury. Myocardial stunning is a transient, reversible dysfunction, while necrosis involves irreversible cell death. The relationship between IPC, stunning, and necrosis is not well understood, requiring further molecular investigation. This study aimed to investigate the proteomic changes associated with IPC, focusing on its relationship with myocardial stunning and necrosis. A novel 13.5-minute ischemia-reperfusion (I/R) rat model was specifically chosen to induce myocardial stunning, providing a unique approach to assess IPC effects in this context. Rats underwent either IPC with two 5-minute ischemia/reperfusion cycles followed by a 13.5-minute ischemic period or the procedure without IPC (no ischemic preconditioning, NIPC). Myocardial samples were collected at early (T1) and 4-hour post-reperfusion (T2) time points for proteomic analysis. Protein levels were quantified by differential labeling using TMTpro reagents, and subsequent liquid chromatography-mass spectrometry. IPC induced upregulation of proteins involved in endocytosis and Fc gamma R-mediated phagocytosis pathways at T1, while downregulating proteins related to tissue remodeling, immune response, and coagulation at T2. Conversely, NIPC exhibited upregulation of proteins associated with tissue damage and inflammation. IPC rats demonstrated enhanced leukocyte migration, complement activation, and immune response between T1 and T2. Consistent proteomic changes were observed between T1 and T2 in IPC vs. NIPC groups, and common alterations between IPC T2 vs. T1 and NIPC T2 vs. T1 comparisons underline shared pathways in cardiac complement and coagulation cascades. Our study reveals distinct proteomic changes induced by IPC in the context of myocardial stunning and necrosis. IPC activates early protective pathways, attenuates tissue damage and inflammation, and preserves myocardial function. These findings underscore IPC's reparative potential and identify myocardial stunning as an important, transient adaptation, which may have implications for supportive clinical management in I/R.

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Multi-omics analysis of early reperfused ischemic heart reveals ERRβ/γ activation protects against acute myocardial infarction injury [CUT&Tag]

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