随意跑轮运动对自发性高血压大鼠功能性抗交感的影响

Ad libidum exercise improves functional sympatholysis'in rats with spontaneous hypertension via the nitricoxide signal pathway

目的 观察8周跑轮运动对自发性高血压大鼠功能性抗交感的影响并探讨一氧化氮(NO)信号途径在其中的作用机制。 方法 将30只自发性高血压大鼠随机分为安静组及运动组,另选取15只健康Wistar大鼠纳入对照组。运动组大鼠进行8周随意跑轮运动,安静组及对照组大鼠饲养期间均特殊干预。通过电刺激(频率包括1Hz、2.5Hz和5Hz)大鼠腰部交感神经诱导缩血管反应,电刺激胫神经诱发小腿三头肌收缩,记录安静时及肌肉收缩时交感神经电刺激引发的股动脉血管电导(FAVC)变化,功能性抗交感用肌肉收缩时FAVC对交感神经电刺激反应的变化率(%FAVC)与安静时变化率的差值表示(△%FAVC=%FAVC肌肉收缩-%FAVC安静)。灌注一氧化氮合酶抑制剂NG-硝基-L-精氨酸甲酯(L-NAME)后重复上述实验并测定FAVC变化。 结果 安静组△%FAVC明显低于对照组[1Hz电刺激时:安静组(1.1±1.6)% VS 对照组(13.5±2.3)%,P<0.05;2.5Hz电刺激时:安静组(7.8±2.1)% VS 对照组(21.6±3.9)%,P<0.05;5Hz电刺激时:安静组(11.6±2.8)% VS 对照组(25.5±4.5)%,P<0.05];运动组△%FAVC明显高于安静组[1Hz电刺激时:运动组(11.5±3.0)% VS 安静组(1.1±1.6)%,P<0.05;2.5Hz电刺激时:运动组(18.9±4.3)% VS 安静组(7.8±2.1)%,P<0.05;5Hz电刺激时:运动组(32.5±5.8)% VS 安静组(11.6±2.8)%,P<0.05];运动组△%FAVC与对照组间差异统计学意义(P>0.05)。灌注L-NAME后,发现对照组及运动组△%FAVC均明显降低[对照组灌注前为(26.1±3.9)%,灌注后为(14.3±2.0)%,P<0.05;运动组灌注前为(31.4±4.1)%,灌注后为(13.2±2.8)%,P<0.05],安静组△%FAVC则显著变化。 结论 随意跑轮运动可能通过NO依赖性信号途径改善自发性高血压大鼠功能性抗交感。

Objective To explore the effect of exercise on functional sympatholysis in rats modeling spontaneous hypertension and the role of the nitric oxide signal pathway. Methods Thirty Wistar rats with spontaneous hypertension were randomly divided into a sedentary group and an exercise group, each of 15, while another fifteen healthy rats acted as controls. The exercise group performed eight weeks of voluntary wheel running exercise while the other two groups did not. The rats were instrumented to stimulate the lumbar sympathetic chain (at 1 Hz, 2.5 Hz or 5 Hz) to induce vasoconstriction and the triceps surae muscle group was forced to contract by stimulating the tibial nerve electrically. The change in the femoral artery vascular conductance (FAVC) in response to sympathetic stimulation was recorded at rest and during contraction. The functional sympatholysis was calculated as the percentage difference in FAVC (△%FAVC) in response to sympathetic stimulation during muscular contraction and at rest (△%FAVC=%FAVC during contraction-%FAVC at rest). After administration of the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME), changes in FAVC were repeatedly determined. Results The average △%FAVC of the sedentary group was significantly lower than that of the control group at all stimulation frequencies, while the average △%FAVC in the exercise group was significantly higher than in the sedentary group. There were no significant differences between the exercise and control groups. After the administration of L-NAME, significant decrease was observed in the average △%FAVCs of the control and exercise groups, but there was no significant change in the sedentary group. Conclusion Voluntary exercise may improve functional sympatholysis in rats with spontaneous hypertension through improving NO-dependent signalling.