TNF-α In Myocardial Tissue Research Articles

Effect of rosiglitazone on myocardial injury in septic rats through NF-κB pathway.

To explore the effect of rosiglitazone on myocardial injury in septic rats through the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway. A total of 60 healthy adult female Sprague-Dawley (SD) rats were randomly divided into 4 groups, namely, group A (sepsis model group, n=15), group B (sham operation group, n=15), group C (sepsis model + 3 mg/kg rosiglitazone, n=15), and group D (sham operation group + 3 mg/kg rosiglitazone, n=15), respectively. After the sepsis model was successfully established, the rats were administered with 3 mg/kg rosiglitazone by gavage, with a gavage volume of 1 mL, once a day for a total of 3 days. Blood was taken from the abdominal aorta, while lactate dehydrogenase (LDH) and creatine phosphokinase kits were used to detect the levels of LDH and creatine phosphokinase in serum. Then, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining was adopted to identify myocardial tissue apoptosis, hematoxylin and eosin staining (H&E) was applied to detect myocardial tissue morphology, and enzyme-linked immunosorbent assay (ELISA) was utilized to examine the protein expression level of tumor necrosis factor-alpha (TNF-α) in rat serum. Subsequently, the messenger ribonucleic acid (mRNA) level of TNF-α in myocardial tissues was measured via fluorescence quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR) method, and the activity of NF-κB was detected by electrophoretic mobility shift assay (EMSA). Compared with those in group A, apoptotic cells in group B and group D were notably increased (p<0.05). At 3 days after administration with rosiglitazone (3 mg/kg), apoptotic cells were markedly decreased (p<0.05). H&E staining results manifested that 3 mg/kg rosiglitazone prominently improved myocardial tissue morphology in rats. The protein level of TNF-α in serum, the mRNA expression level of TNF-α in myocardial tissues, and the activity of NF-κB in group C treated with rosiglitazone were lower than those in group A (p<0.05). Rosiglitazone can alleviate myocardial injury in septic rats by suppressing the TNF-α expression and this process is associated with the regulation on the NF-κB signal transduction pathway.

β1 receptor blocker decreases the myocardial inflammation in the sepsis adult rats through inhibition of TLR4/NF-ΚB signaling pathway

To explore whether β1 receptor blocker could decrease the myocardial inflammation through the Toll-like receptor 4/nuclear factor-ΚB (TLR4/NF-ΚB) signaling pathway in the sepsis adult rats. Sixty male Wistar rats (250-300 g) aged 3 months old were allocated to four groups by random number table (n = 15): sham operation group (S group), sepsis model group (CLP group), β1 receptor blocker esmolol intervention group (ES group), and inhibitor of the TLR4 E5564 intervention group (E5564 group). The rat sepsis model was established by cecal ligation and puncture (CLP); S group of rats underwent only an incision. Rats in S group, CLP group and E5564 group were subcutaneous injected with 0.9% sodium chloride (NaCl) 2.0 mL/kg. Besides, the rats in ES group were injected with esmolol (15 mg×kg-1×h-1) by micro pump through the caudal vein. The rats in E5564 group were injected with E5564 (0.3 mg×kg-1×h-1) by micro pump through the caudal vein 1 hour before the CLP surgery. Samples were collected 6 hours after the modelling in each group. The average arterial pressure (MAP) and cardiac output index (CI) were monitored by PU electrical conduction ECG monitor. The levels of serum cardiac troponin I (cTnI), interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) were detected by enzyme linked immunosorbent assay (ELISA). The expressions of TLR4, NF-ΚB p65, IL-1β, TNF-α in myocardial tissue was detected by Western Blot. There was no significant difference in MAP in each group. Compared with the S group, the CI in the CLP group was significantly decreased, the levels of serum cTnI, IL-1β, TNF-α were significantly increased, the protein expressions of myocardial tissue TLR4, NF-ΚB p65, IL-1β and TNF-α were significantly increased. Compared with the CLP group, the CI in the ES group and E5564 group were significantly increased (mL×s-1×m-2: 58.6±4.3, 58.9±4.4 vs. 41.2±3.9, both P < 0.01), the levels of serum cTnI, IL-1β and TNF-α were significantly decreased [cTnI (μg/L): 1 113.81±26.64, 1 115.74±25.90 vs. 1 975.96±42.74; IL-1β (ng/L): 39.6±4.3, 38.9±4.4 vs. 61.2±3.9; TNF-α (ng/L): 43.1±2.8, 48.7±2.6 vs. 81.3±4.4, all P < 0.01], the protein expressions of myocardial tissue NF-ΚB p65, IL-1β, TNF-α were significantly decreased (NF-ΚB p65/β-actin: 0.31±0.03, 0.43±0.04 vs. 0.85±0.08; IL-1β/β-actin: 0.28±0.05, 0.32±0.03 vs. 0.71±0.06; TNF-α/β-actin: 0.18±0.04, 0.28±0.03 vs. 0.78±0.07, all P < 0.01), but there was no significant difference in protein expression of TLR4 (TLR4/β-actin: 0.89±0.07, 0.87±0.09 vs. 0.95±0.09, both P > 0.05). There was no significant difference in CI, the levels of serum cTnI, IL-1β, TNF-α, and the protein expressions of myocardial tissue TLR4, NF-ΚB p65, IL-1β, TNF-α between ES group and E5564 group (all P > 0.05). β1 receptor blocker esmolol may inhibit myocardial inflammatory response in sepsis adult rats through TLR4/NF-ΚB signaling pathway, thereby alleviating sepsis-induced myocardial injury.

Heparin Added to Cardioplegic Solution Inhibits Tumor Necrosis Factor-α Production and Attenuates Myocardial Ischemic-Reperfusion Injury

Tumor necrosis factor (TNF)-alpha is known to be a proinflammatory cytokine that has a pronounced negative inotropic effect and plays an important role in ischemic-reperfusion injury. Twenty isolated rat hearts were randomly divided equally into two groups (heparin and non-heparin) and were perfused with a Krebs-Henseleit solution using a modified Langendorff model. The influence of heparin on the synthesis and release of TNF-alpha by isolated rat hearts after 1 h of global cardioplegic ischemia and on left ventricular (LV) performances during 30 min of postischemic reperfusion was investigated. Significant mean (+/- SEM) amounts of TNF-alpha in myocardial tissue (1,149 +/- 33.7 pg/g) and effluent (951.8 +/- 27.3 pg/mL) from the coronary sinus were detected after global cardioplegic ischemia. The addition of heparin to the cardioplegic solution significantly improved the recovery of LV function in the postischemic heart (p < 0.0001 for all measurements). TNF-alpha protein production in the heparin-treated hearts was below detectable levels despite a postischemic increase of TNF-alpha messenger RNA expression in both heparin-treated hearts and nontreated hearts (0.71 +/- 0.06 and 0.8 +/- 0.12 relative optical density, respectively). This study shows, for the first time, that heparin causes the inhibition of TNF-alpha protein synthesis and release from the isolated ischemic rat heart within the posttranscriptional stage, and that it prevents the depression of LV function caused by ischemic-reperfusion injury.

Improvement of preservation with cardioplegic solution by nitroglycerin-induced delayed preconditioning is mediated by calcitonin gene-related peptide

Improvement of preservation with cardioplegic solution by nitroglycerin-induced delayed preconditioning was studied in the isolated rat heart. The isolated rat heart was arrested using St. Thomas Hospital solution, and then reperfused with normothermic Krebs–Henseleit solution for 40 min after a 4-h hypothermic ischemic period. Heart rate, coronary flow, left ventricular pressure and the maxium value of the first derivatives of left ventricular pressure (±d p/d t max) were recorded, and plasma concentrations of CGRP-like immunoreactivity (CGRP-LI) and nitric oxide (NO), tumor necrosis factor-alpha (TNF-α) in myocardial tissues, and creatine kinase in coronary effluent were measured. Delayed preconditioning was induced by i.v. injection of nitroglycerin 24 h before the experiment. Nitroglycerin (60 μg/kg or 120 μg/kg) caused an improvement of cardiac function, a decrease in the release of creatine kinase in coronary effluent and a decrease in the content of TNF-α in myocardial tissues. Nitroglycerin significantly increased plasma concentrations of CGRP and NO. After pretreatment with capsaicin, which depletes neurotransmitters in sensory nerves, or methylene blue, a selective guanylate cyclase inhibitor, the protection and the elevated release of CGRP induced by nitroglycerin were abolished. The present study suggests that improvement of preservation with cardioplegic solution by nitroglycerin-induced delayed preconditioning is due to stimulation of CGRP release in the rat heart, and that the protection of CGRP-mediated nitroglycerin is related to inhibition of TNF-α production.

Monophosphoryl lipid A-induced delayed preconditioning is mediated by calcitonin gene-related peptide

The delayed preconditioning of the heart by monophosphoryl lipid A is mediated by endogenous nitric oxide (NO), and the cardioprotection afforded by nitroglycerin is related to stimulation of calcitonin gene-related peptide (CGRP) release. The objective of this study was to explore whether improvement of preservation with cardioplegia by monophosphoryl lipid A is mediated by CGRP. In addition, we examined the effect of monophosphoryl lipid A on the tumor necrosis factor-α (TNF-α) content of myocardial tissues. The isolated rat heart was perfused in the Langendorff mode. Heart rate, coronary flow, left-ventricular pressure, and its first derivatives (±d p/d t max) were recorded, and plasma levels of NO and CGRP, the release of creatine kinase in coronary effluent and the content of TNF-α in myocardial tissues were measured. Hypothermic ischemia for 4 h caused a decline in cardiac function, and an increase in the release of creatine kinase and in the content of TNF-α. Pretreatment with monophosphoryl lipid A (500 μg/kg, i.p.) for 24 h improved the recovery of cardiac function and reduced the release of creatine kinase concomitantly with a decrease in the content of cardiac TNF-α. Monophosphoryl lipid A markedly increased plasma concentrations of CGRP and NO. After pretreatment with l-nitroarginine methyl ester ( l-NAME), the cardioprotection and the increased release of NO and CGRP induced by monophosphoryl lipid A were abolished. Capsaicin also abolished the cardioprotection and the increased release of CGRP induced by monophosphoryl lipid A, but did not affect the content of NO. The results suggest that monophosphoryl lipid A-induced preconditioning enhances preservation with cardioplegia and that the protective effects of monophosphoryl lipid A are related to stimulation of CGRP release.