[Effects of Shenfu injection on the expression of transcription factors T-bet / GATA-3 in pigs with post-resuscitation myocardial dysfunction]

Abstract

Objective: To 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 8 minutes 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) and γ-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-γ and 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, all P < 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, all P < 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, both P < 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, both P < 0.05]. The parameters in SFI group were significantly improved compared with those of the EP group.

Conclusions: Myocardial 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.