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目的在体研究甲状腺素(thyroid hormone,TH)对慢性心力衰竭(heart failure,HF)大鼠血流动力学及心脏Ca~(2+)-调神经磷酸酶(calcineurin,CaN)-T细胞核因子3(nuclear factor 3 of activated T cells,NFAT3)通路的影响。方法 SD大鼠90只随机分为3组,各组30只:(1)假手术组(sham组);(2)HF模型组(HF组);(3)TH治疗组(TH组)。缩窄腹主动脉建立HF动物模型,TH组术后灌胃予左甲状腺素钠[1.5μg/(100 g·d)]。各组大鼠喂养8周后测定有创血流动力学指标,取材称量全心湿质量(heart wet weight,HW)、全肺湿质量(lung weight,LW),计算心质量指数[HW/体质量(body weight,BW)]、肺质量指数(LW/BW),测定心肌[Ca~(2+)]i浓度及CaN活性,Western blot检测CaN-A、总NFAT3(T-NFAT3)、磷酸化NFAT3(P-NFAT3)蛋白表达水平。结果(1)TH治疗显著改善HF大鼠收缩压(systolic pressure,SP)、左心室收缩压(left intraventricular systolic pressure,LVSP)、+dp/dt max、左心室舒张压(left ventricular diastolic pressure,LVDP)、左心室舒张末期压力(left ventricular end-diastolic pressure,LVEDP)、-dp/dt max;TH组与HF组心率比较,差异无统计学意义(P>0.05)。(2)TH组HW/BW[(3.44±0.27)mg/g vs.(4.18±0.28)mg/g,P<0.01]及LW/BW[(8.02±0.41)mg/g vs.(8.56±0.45)mg/g,P<0.01]均较HF组有所降低,差异有统计学意义。(3)与HF组比较,TH组大鼠[Ca~(2+)]i[(115.50±10.76)nmol/L vs.(159.36±7.21)nmol/L,P<0.01]及CaN活性[(21.33±2.35)nmol·min~(-1)·mg~(-1)protein vs.(42.96±3.36)nmol·min~(-1)·mg~(-1)protein,P<0.05]均显著降低。(4)HF组P-NFAT3表达(0.41±0.10 vs.0.80±0.11,P<0.01)及P-NFAT3/T-NFAT3比值(0.13±0.03 vs.0.25±0.04,P<0.01)较Sham组显著减少,差异有统计学意义;TH组P-NFAT3表达(0.86±0.11vs.0.41±0.10,P<0.01)及P-NFAT3/T-NFAT3比值(0.27±0.03 vs.0.13±0.03,P<0.01)较HF组则显著增加,差异有统计学意义;虽TH组P-NFAT3表达较Sham组有所增加,而TH组P-NFAT3/T-NFAT3比值与Sham组比较,差异无统计学意义(P=0.193)。结论 TH通过改善心肌钙稳态,减少对Ca N的病理激活而维持下游NFAT3蛋白磷酸化状态,使HF大鼠的解剖病理和血流动力学获益。
Objective To study the effects of thyroid hormone (TH) on the hemodynamics and calcineurin (CaN) -T nuclear factor-kappa B in heart failure rats with chronic heart failure (HF) 3 (nuclear factor 3 of activated T cells, NFAT3) pathway. Methods Ninety Sprague-Dawley rats were randomly divided into three groups (30 rats in each group): (1) Sham group; (2) HF model group; (3) TH treatment group. Narrowed the abdominal aorta to establish HF animal model, TH group was given intragastric levothyroxine [1.5μg / (100g · d)]. The rats in each group were sacrificed 8 weeks after the establishment of invasive hemodynamic parameters, weighed whole heart wet weight (HW), lung wet weight (LW), calculated heart mass index [HW / Body weight (BW)] and pulmonary mass index (LW / BW) were measured to determine the concentration of [Ca2 +] i and the activity of CaN in myocardium. CaN-A and TATF NFAT3 Phosphorylation of NFAT3 (P-NFAT3) protein expression levels. Results (1) TH treatment significantly improved systolic blood pressure (SP), left intraventricular systolic pressure (LVSP), + dp / dt max, left ventricular diastolic pressure (LVDP ), Left ventricular end-diastolic pressure (LVEDP) and - dp / dt max. There was no significant difference in heart rate between TH group and HF group (P> 0.05). (2) HW / BW [(3.44 ± 0.27) mg / g vs. (4.18 ± 0.28) mg / g, P <0.01] and LW / BW [(8.02 ± 0.41) mg / g vs. 0.45) mg / g, P <0.01] than the HF group, the difference was statistically significant. (3) Compared with HF group, [Ca ~ (2 +)] i [(115.50 ± 10.76) nmol / L vs. (159.36 ± 7.21) nmol / L, P <0.01] 21.33 ± 2.35) nmol · min -1 · mg -1 protein vs. 42.96 ± 3.36 nmol · min -1 · mg -1 protein, P <0.05] reduce. (4) The expression of P-NFAT3 in HF group was significantly higher than that in Sham group (0.41 ± 0.10 vs.0.80 ± 0.11, P <0.01), and P-NFAT3 / T-NFAT3 (0.13 ± 0.03 vs.0.25 ± 0.04, P <0.01) (P <0.01). The P-NFAT3 expression in TH group (0.86 ± 0.11 vs.0.41 ± 0.10, P <0.01) and P-NFAT3 / T-NFAT3 ratio ) In HF group was significantly higher than that in HF group, but the difference was statistically significant. Although the expression of P-NFAT3 in TH group was higher than that in Sham group, the difference was not statistically significant (P> 0.05) between TH-group and Sham group P = 0.193). Conclusions TH can maintain the phosphorylation status of NFAT3 protein downstream of heart and improve the anatomical pathology and hemodynamics of HF rats by improving myocardial calcium homeostasis and reducing the pathological activation of CaN.