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OBJECTIVE@#To investigate whether Shenfu Injection (SFI, ) can alleviate post-resuscitation myocardial dysfunction by inhibiting the inflammatory response.@*METHODS@#After 8 min of ventricular fibrillation and 2 min of basic life support, 24 pigs were randomly divided into 3 groups (n=8), which were given intravenous bolus injections of SFI (1.0 mL/kg), epinephrine (EP, 0.02 mg/kg) and normal saline (SA), respectively. The animals were sacrificed at 24 h after restoration of spontaneous circulation (ROSC), and serum interleuking-6 (IL-6) and tumor necrosis factor-α (TNF-α) levels were measured by enzyme-linked immunosorbent assay (ELISA); expressions of Toll-like receptor 4 (TLR4)/nuclear factor kappa B (NF-κB) mRNAs and proteins were determined by RT-PCR and Western blot, respectively.@*RESULTS@#Compared with the EP and the SA groups, the ultrastructure of myocardial cells were slightly damaged and the systolic function of the left ventricle was markedly improved in the SFI group at 24 h after ROSC (P<0.05). In addition, compared with the EP and SA groups, the SFI group also showed significantly reduced levels of serum IL-6 and TNF-α, protein and mRNA levels of myocardial NF- κB and TLR4 (P<0.05).@*CONCLUSIONS@#Activation of TLR4/NF-κB signaling pathway may be involved in the pathological mechanisms of post-resuscitation myocardial dysfunction. SFI may block NF-κB-mediated inflammatory response by reducing the activity of NF- κB and the level of TNF-α, thus playing a protective role in post-resuscitation myocardial dysfunction.
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Objective To investigate the characteristics of myocardial injury and its underlying mechanism in rats resuscitated from cardiac arrest. Methods Forty-two male Wistar rats were randomly(random number) assigned into the post-resuscitation (PR) 4 h, PR 24 h, PR 48 h, and sham groups. Ventricular fibrillation was induced by transcutaneous electrical epicardium stimulation and untreated for 6 min, followed by cardiopulmonary resuscitation (CPR). Myocardial function, glucose metabolism, myocardial ultrastructure, the status of mitochondrial permeability transition pore (MPTP) and mitochondrial membrane potential (MMP) were evaluated at different time points. Results Myocardial dysfunction was found at 4 h after restoration of spontaneous circulation (ROSC). The ejection fraction and cardiac output were decreased (all P<0.01), the diastole left ventricular posterior wall became thicker (P<0.01), and the end-diastolic volume was reduced (P<0.05). However, cardiac function was recovered almost completely at 48 h after ROSC. The PR 4 h group had a higher SUVmax, a more obvious decreased absorbance, and a lower MMP than the sham group (all P<0.01), but no statistically significant differences were noted between the PR 48 h group and the sham group (P>0.05). At 4 h and 24 h after ROSC, the mitochondria was swollen and the mitochondrial crista was sparse, but the myocardial ultrastructure was complete. Conclusions Post resuscitation myocardial dysfunction occurs after ROSC and the myocardial dysfunction is completely reversible at 48 h after ROSC, which may be related to the reversibility of myocardial injury and the gradual recovery of mitochondrial structure and function.
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ObjectiveTo examine whether Shenfu injection (SFI) reduces post-resuscitation myocardial dysfunction in a pig model by modulating expression imbalance of transcription factors of regulatory T cell, namely GATA-3 and T-bet.Methods Thirty pigs were randomly divided into sham group (n = 6) and cardiopulmonary resuscitation (CPR) group (n = 24) according to the random number table method, and the pigs in the CPR group were randomly subdivided into normal saline (NS) group, epinephrine (EP) group, and SFI group (n = 8 per group). After 8minutes of untreated ventricular fibrillation (VF) followed by 2 minutes of CPR, animals in three groups respectively received central venous injection of either 20 mL SFI (1.0 mL/kg, SFI group), EP (0.02 mg/kg, EP group) or NS (NS group). Blood samples were obtained before VF and 0.5, 2, 6 hours after restoration of spontaneous circulation (ROSC), and the parameters of hemodynamics and oxygen metabolism were determined. Surviving pigs were sacrificed at 24 hours after ROSC, the pathological changes in myocardium were observed, the levels of interleukin-4 (IL-4), tumor necrosis factor-α (TNF-α) andγ-interferon (IFN-γ) were measured by enzyme linked immunosorbent assay (ELISA), and expressions of protein and mRNA of GATA-3 and T-bet were determined by Western Blot and quantitative real-time polymerase chain reaction (RT-qPCR), respectively.Results Six pigs of three resuscitation groups were successfully resuscitated. The CPR time, number of defibrillation, defibrillation energy, and ROSC time were significantly decreased in the EP and SFI groups compared with those in the NS group. Compared with the sham group, the parameters of left ventricular systolic function and oxygen metabolism were significantly decreased, myofibril organelles were extensively damaged, and progressive and severe deterioration of the myocardium was found, and mitochondrial structure was not recognizable in the NS group; the level of IL-4 in myocardium were markedly decreased, while that of TNF-α, IFN-γand IFN-γ/ IL-4 [reflecting helper T cell 1/2 (Th1/Th2)] were significantly increased. Protein and mRNA expressions of GATA-3 were markedly reduced in the myocardium of pigs in the NS group compared with that of the sham group at 24 hours after ROSC, while T-bet was significantly increased. Compared with the NS group, animals treated with SFI had minimal myocardial intracellular damage, with decreased heart rate (HR, bpm: 90.33±3.79 vs. 106.83±5.36) and increased mean arterial pressure (MAP), cardiac output (CO), oxygen delivery (DO2), and oxygen consumption (VO2) at 6 hours after ROSC [MAP (mmHg, 1 mmHg = 0.133 kPa): 107.67±1.96 vs. 86.83±1.85, CO (L/min): 2.47±0.08 vs. 2.09±0.04, DO2 (mL/min): 364.31±4.21 vs. 272.33±3.29, VO2 (mL/min): 95.00±2.22 vs. 82.50±2.28, allP<0.05]. Compared with the NS groups at 24 hours after ROSC, level of IL-4 was markedly increased in myocardial cells (ng/L: 33.80±3.06 vs. 16.15±1.34,P< 0.05), while the levels of TNF-α, IFN-γ and IFN-γ/IL-4 were lowered significantly [TNF-α (ng/L): 18.16±0.71 vs. 29.64±1.89, IFN-γ (ng/L): 373.75±18.36 vs. 512.86±27.86, IFN-γ/IL-4: 16.15±1.34 vs. 33.80±3.06, allP< 0.05], and myocardial T-bet protein and mRNA expressions were reduced [T-bet protein (gray value): 0.41±0.07 vs. 0.59±0.11, T-bet mRNA (2-ΔΔCt): 4.37±0.21 vs. 7.57±0.55, bothP< 0.05], furthermore, myocardial GATA-3 protein and mRNA expressions were significantly up-regulated in SFI group [GATA-3 protein (gray value): 0.25±0.07 vs. 0.16±0.07, GATA-3 mRNA (2-ΔΔCt): 0.63±0.07 vs. 0.34±0.05, bothP< 0.05]. The parameters in SFI group were significantly improved compared with those of the EP group.ConclusionsMyocardial immune dysfunction is induced by Th1/Th2 imbalance following myocardial injury subsequent to CPR in pigs. SFI can attenuate myocardial injury and regulate myocardial immune disorders, protect post-resuscitation myocardial injury by modulating expression imbalance of transcription factors GATA-3 and T-bet.
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BACKGROUND:Recent studies have shown that α2-adrenergic agonists can reduce postresuscitation myocardial injury. This study was undertaken to observe changes of hemodynamics, myocardial injury markers cTnT and cardiac morphology by establishing a cardiopulmonary resuscitation model with rabbits, and to detect whether α-methyl norepinephrine (α-MNE) can reduce the myocardial injury after CPR and improve cardiac function. METHODS:Eighteen health rabbits, weighing 2.5-3.5 kg, both male and female, were provided by the Lanzhou Institute of Veterinary Medicine. After setting up a rabbit model of cardiopulmonary resuscitation, 18 rabbits were randomly divided into three groups. The rabbits in group A as an operation-control group were subjected to anesthesia, endotracheal intubation, and surgery without induction of ventricular fibrillation. The rabbits in group B as an epinephrine group were administered with 30 g/kg epinephrineduring CPR. The rabbits in group C as a MNE group were administered with 100 g/kg a-MNE during CPR. The left ventricular end-diastolic pressure (LVEDP), left ventricular pressure rise and fall rate (±dp/dt) and serum concentrations of BNP were measured. Statistical package of SPSS 10.0 was used for data analysis and significant differences between means were evaluated by ANOVA. RESULTS:Compared to group A, the LVEDP of other two groups increased respectively (P<0.01 all), and peak±dp/dt decreased in the other two groups (P<0.01). The increase of LVEDP was lower in group C than in group B (P<0.05), whereas peak±dp/dt was higher in group C than in group B (P<0.05) at the same stage. Compared to group A, the cTnT of the remaining two groups increased, respectively (P<0.01), and peaked at 30 minutes. cTnT was less elevated in group C than in group B (P<0.05) during the same period. In groups B and C, myocardial injury was seen under a light microscope, but the injury in group C was lighter than that in group B. CONCLUSION:Methylnorepinephrine can lessen myocardial dysfunction after CPR.