自发性高血压大鼠运动降压与动脉压力反射敏感性的相关性(英文)

Correlation between exercise lowering blood pressure and arterial baroreflex sensitivity in spontaneously hypertensive rats

目的:探讨运动训练对自发性高血压大鼠(SHR)动脉压力反射(BRS)敏感性的影响及血压与BRS的相关性。方法:雄性SHR大鼠和正常血压Wistar大鼠各20只被随机各分成常态(安静)组和运动组,每组10只。两运动组大鼠进行8周跑台训练(20 m/min,60 min/d,6 d/周)。采用尾套法测量清醒大鼠的收缩压(SBP)和心率(HR)。静脉注射苯肾上腺素(PE)和硝普钠(NP)分别诱发降压反射和升压反射,以反射前后的心率与平均动脉压变化值之比(HR/MAP)作为降压反射敏感性(BRS-PE)和升压反射敏感性(BRS-NP)指标。结果:8周运动结束时,SHR运动组静息SBP[(163.6±10.7)mmHg比(180.0±8.5)mmHg]和HR[(345.0±9.8)次/min比(368.4±13.3)次/min]较SHR常态组显著下降,P均<0.01。Wistar运动组静息SBP与常态组无明显差异(P>0.05),但HR较常态组显著下降[(343.9±10.2)次/min比(362.2±13.0)次/min,P<0.05]。SHR运动组的BRS-PE[(1.32±0.22)bpm/mmHg比(0.89±0.13)bpm/mmHg]和BRS-NP[(1.21±0.26)bpm/mmHg比(0.60±0.09)bpm/mmHg]较SHR常态组明显提高,P均<0.01,但仍低于Wistar常态组的BRS[BRS-PE:(1.96±0.23)bpm/mmHg,BRS-NP:(1.32±0.17)bpm/mmHg]。Pearson线性相关分析显示,SHR常态组和运动组的平均动脉压与BRS呈显著负相关(r=-0.734,P<0.01)。结论:运动训练能显著降低SHR的血压,它与运动改善压力反射敏感性有关,提示增强的压力反射功能可能是高血压运动疗法的重要机制。

Objectives： To explore the influence of exercise training on the arterial baroreflex sensitivity （BRS） and correlation between blood pressure and BRS in spontaneously hypertensive rats （SHR）. Methods： Male SHR （n= 20） and normotensive Wistar rats （n= 20） were randomly assigned to normality group and exercise group, n= 10 in each group. Rats in two exercise groups received treadmill training at a speed of 20 m/min for 60 min/d, 6 d/w for eight weeks. Systolic blood pressure （SBP） and heart rate （HR） were measured using a tail-cuff method in a conscious state. Intravenous injections of phenylephrinc （PE） and sodium nitroprusside （NP） were used to induce depressor and pressor reflex respectively. The ratio of HR over mean arterial pressure （MAP） （HR/MAP） after administration of PE or NP was regarded as an index of depressor reflex sensitivity （BRS-PE） and pressor reflex sensivity （BRS-NP）. Results： After eight-week exercise training, compared with SHR normality group, there were significant reduction in resting SBP [ （180±8.5） mmHg vs. （163.6±10.7） mmHg] and in HR [ （368.4±13.3） beats/ min vs. （345.0±9.8） beats/mini in SHR exercise group, P〈0.01 both. However, there was no significant difference in resting SBP between Wistar exercise and normality groups （P 〉0.05）, compared with Wistar normality group, there was significant reduction in HR [ （362.2±13.0） beats/min vs. （343.9 ±10.2） beats/min, P 〈 0.05] in Wistar exercise group. Compared with SHR normality group, there were significant rise in BRS [BRS-PE： （0.89 ±0.13） bpm/mmHg vs. （1.32 ±0.22） bpm/mmHg, BRS-NP： （0.60±0.09） bpm/mmHg vs. （1.21±0.26） bpm/mmHg, P〈0.01] in SHR exercise group, but still lower than those of Wistar normality group [BRS-PE： （1.96±0.23） bpm/mmHg, BRS-NP： （1.32± 0. 17） bpm/mmHg]. Pearson linear correlation analysis indicated that MAP was significantly inversely correlated with BRS （r =- 0. 734, P〈0.01） in SHR normality and exercise group. Conclusion： Exercise training may significantly decrease SHR blood pressure; it is related to improved baroreflex sensitivity induced by exercise, indicating that enhanced baroreflex may be an important mechanism of exercise therapy in hypertensive patients.