目的观察β3肾上腺素能受体(β3-AR)对心肌成纤维细胞(CFB)纤维化的作用,并探讨其机制。方法分离Sprague-Dawley(SD)大鼠乳鼠的CFB体外培养,CFB分为4组,即阴性对照组、β3-AR激动剂处理组(BRL组)、β3-AR拮抗剂处理组(SR组)和阳性对照组。阴性对照组CFB的培养基中不加任何药物干预;BRL组和SR组,在CFB培养基中分别先加入10^-6mol/L的血管紧张素Ⅱ(AngⅡ),1h后再分别加入β3-AR激动剂BRL3734410^-5mol/L或β3-AR拮抗剂SR59230A10^-5mol/L;阳性对照组,CFB培养基中仅加入10^-6mol/L的AngⅡ。水溶性四唑盐-1(WST-1)法检测CFB增殖情况。蛋白印迹法检测β3-AR、转化生长因子β1受体(TGF-β1-R)、转化生长因子β(TGF-β)1、TGF-β受体激酶底物Smad-2、磷酸化Smad-2(p-Smad-2)、I型胶原以及Ⅲ型胶原蛋白的表达水平。结果(1)各组乳鼠CFB增殖情况的检测结果:BRL组乳鼠CFB增殖强度明显大于阴性对照组、SR组和阳性对照组(1.08±0.01比0.97±0.03、1.03±0.01和1.05±0.01,P均〈0.05)。阳性对照组乳鼠CFB增殖强度明显大于SR组和阴性对照组(P均〈0.05)。SR组乳鼠CFB增殖强度明显大于阴性对照组(P〈0.05)。(2)各组乳鼠CFBβ3.AR蛋白表达水平的检测结果:BRL组乳鼠CFBβ3-AR蛋白表达水平明显高于阳性对照组、SR组和阴性对照组(0.246±0.004比0.078±0.006、0.054±0.001和0.015±0.003,P均〈0.05)。阳性对照组乳鼠CFBβ3-AR蛋白表达水平明显高于SR组和阴性对照组(P均〈0.05)。SR组乳鼠CFBβ3-AR蛋白表达水平则明显高于阴性对照组(P〈0.05)。(3)各组乳鼠CFBTGF-β1-R蛋白表达水平的检测结果:BRL组乳鼠CFBTGF-β1-R蛋白表达水平明显高于阳性对照组、SR组和阴性对照组(0.60±0.01比0.31±0.02、0.28±0.02和0.06±0.01,P均〈0.05)。阳性对照组乳鼠CFBTGF
Objective To observe the effect of β1 adrenergie receptor (β1-AR) on fibrosis in cardiac fibroblasts (CFBs) and explore the related mechanisms. Methods Neonatal CFBs were divided into negative control group (N-CFC) :CFBs without any intervention; group treated with β1 adrenergic receptor agonist ( Ang Ⅱ -CFC-β1-AR BRL) : CFBs treated with 10-6 mol/L angiotensin Ⅱ ( Ang Ⅱ ) , 1 hour later treated with 10-s mol/L β1 adrenergic receptor agonist (β1-AR BRL37344 ); group treated with β1 adrenergie receptor antagonist ( Ang Ⅱ -CFC-β1-AR SR) : CFBs treated with 10-6 mo]/L Ang Ⅱ , 1 hour later treated with 10-5 mol/L β1 adrenergic receptor antagonist (β1-AR SR.59230A) ; and positive control group (Ang Ⅱ-CFC ) : CFBs treated with 10-6 mol/L Ang Ⅱ only. Proliferation of CFBs was detected by the method of WST-1. Protein expression of β1-AR, transforming growth factor β1 receptor (TGF-β1-R) , transforming growth factor β1 ( TGF-β1 ) , Smad-2, phospho-Smad-2 (p-Smad-2) , collagen- I ( COL- Ⅰ ) and collagen- Ⅱ ( COL- m ) was determined by Western blot assay. Results ( 1 ) The proliferation of CFBs was the highest in Ang Ⅱ -CFC-β1-AR BRL, followed by Ang Ⅱ -CFC-β1-AR SR and AngⅡ-CFC group ( all P〈0.05 vs. N-CFC group). (2) The protein expression level of β1-AR, TGF-β1-R, TGF-β1 and p-Smad-2 was in the same order as proliferation of CFBs. (3) The expression level of COL- Ⅰ and COL-Ⅲ protein was also in the same order as proliferation of CFBs. Conclusion Activation of β1-AR may promote fibrosis of CFBs through the TGF-[3/Smad signaling pathway and thus aggravate myocardial remodeling.