Klippel Brunella F, Duemke Licia B, Leal Marcos A, Friques Andreia G F, Dantas Eduardo M, Dalvi Rodolfo F, Gava Agata L, Pereira Thiago M C, Andrade Tadeu U, Meyrelles Silvana S, Campagnaro Bianca P, Vasquez Elisardo C
Laboratory of Translational Physiology, Federal University of Espirito Santo Vitoria, Brazil.
Pharmaceutical Sciences Graduate Program, Vila Velha University Vila Velha, Brazil.
Front Physiol. 2016 Jun 7;7:211. doi: 10.3389/fphys.2016.00211. eCollection 2016.
It has been previously shown that the probiotic kefir (a symbiotic matrix containing acid bacteria and yeasts) attenuated the hypertension and the endothelial dysfunction in spontaneously hypertensive rats (SHR). In the present study, the effect of chronic administration of kefir on the cardiac autonomic control of heart rate (HR) and baroreflex sensitivity (BRS) in SHR was evaluated.
SHR were treated with kefir (0.3 mL/100 g body weight) for 60 days and compared with non-treated SHR and with normotensive Wistar-Kyoto rats. Cardiac autonomic vagal (VT) and sympathetic (ST) tones were estimated through the blockade of the cardiac muscarinic receptors (methylatropine) and the blockade of β1-adrenoceptor (atenolol). The BRS was evaluated by the tachycardia and bradycardia responses to vasoactive drug-induced decreases and increases in arterial blood pressure (BP), respectively. Additionally, spontaneous BRS was estimated by autoregressive spectral analysis.
Kefir-treated SHR exhibited significant attenuation of basal BP, HR, and cardiac hypertrophy compared to non-treated SHR (12, 13, and 21%, respectively). Cardiac VT and ST were significantly altered in the SHR (40 and ~90 bpm) compared with Wistar rats (120 and 30 bpm) and were partially recovered in SHR-kefir (90 and 25 bpm). SHR exhibited an impaired bradycardic BRS (50%) compared with Wistar rats, which was reduced to 40% in the kefir-treated SHR and abolished by methylatropine in all groups. SHR also exhibited a significant impairment of the tachycardic BRS (23%) compared with Wistar rats and this difference was reduced to 8% in the SHR-kefir. Under the action of atenolol the residual reflex tachycardia was smaller in SHR than in Wistar rats and kefir attenuated this abnormality. Spectral analysis revealed increased low frequency components of BP (3.5-fold) and pulse interval (2-fold) compared with Wistar rats and these differences were reduced by kefir-treatment to ~1.6- and ~1.5-fold, respectively. Spectral analysis also showed an impairment of spontaneous BRS in SHR, but kefir-treatment caused only a tendency to reverse this result.
The novelty of this study is that daily chronic consumption of a low dose of kefir reduced the impairment of the cardiac autonomic control of HR and of the impaired BRS in SHR.
先前的研究表明，益生菌开菲尔（一种含有乳酸菌和酵母菌的共生基质）可减轻自发性高血压大鼠（SHR）的高血压和内皮功能障碍。在本研究中，评估了长期给予开菲尔对SHR心率（HR）的心脏自主控制和压力反射敏感性（BRS）的影响。
用开菲尔（0.3 mL/100 g体重）治疗SHR 60天，并与未治疗的SHR和正常血压的Wistar-Kyoto大鼠进行比较。通过阻断心脏毒蕈碱受体（甲基阿托品）和阻断β1-肾上腺素能受体（阿替洛尔）来估计心脏自主迷走神经（VT）和交感神经（ST）张力。分别通过对血管活性药物诱导的动脉血压（BP）降低和升高的心动过速和心动过缓反应来评估BRS。此外，通过自回归谱分析估计自发性BRS。
与未治疗的SHR相比，开菲尔治疗的SHR的基础血压、HR和心脏肥大显著减轻（分别为12%、13%和21%）。与Wistar大鼠（120和30 bpm）相比，SHR的心脏VT和ST显著改变（40和90 bpm），在SHR-开菲尔组中部分恢复（90和25 bpm）。与Wistar大鼠相比，SHR的心动过缓BRS受损（50%），在开菲尔治疗的SHR中降至40%，在所有组中均被甲基阿托品消除。与Wistar大鼠相比，SHR的心动过速BRS也显著受损（23%），在SHR-开菲尔组中这一差异降至8%。在阿替洛尔的作用下，SHR的残余反射性心动过速比Wistar大鼠小，开菲尔减轻了这种异常。谱分析显示，与Wistar大鼠相比，BP的低频成分增加（3.5倍），脉搏间期增加（2倍），开菲尔治疗使这些差异分别降至1.6倍和~1.5倍。谱分析还显示SHR的自发性BRS受损，但开菲尔治疗仅导致该结果有逆转的趋势。
本研究的新颖之处在于，每天长期食用低剂量的开菲尔可减少SHR中HR的心脏自主控制受损和BRS受损。
