仿真针刺对自发性高血压大鼠心肌生物钟基因Bmal1、Clock、Per2表达的影响

Effects of simulated acupuncture on myocardial circadian clock genes Bmal1, Clock and Per2 in spontaneously hypertensive rats

目的:探讨仿真针刺不同时间点干预对自发性高血压大鼠(SHR)收缩压及心肌生物钟基因表达的影响,包括大脑和肌肉芳香烃受体核转运蛋白样蛋白1(Bmal1)、昼夜节律运动输出周期故障(Clock)、周期蛋白2(Per2)。方法:24只雄性SHR随机分为SHR模型组、14时针刺组、21时针刺组,每组8只;另取7只雄性WKY大鼠作为对照。借助ATP-1仿真针刺手法仪在相应时间点对14时针刺组和21时针刺组大鼠进行仿真针刺治疗,取双侧足三里、曲池穴,隔日1次,共10次。治疗前后分别测量大鼠的尾动脉收缩压。末次干预后,分离心肌组织。PCR检测大鼠心肌Bmal1、Clock、Per2的mRNA表达,Western blot检测心肌Bmal1、Clock、Per2的蛋白表达。结果:(1)治疗后,与SHR模型组相比,14时针刺组和21时针刺组大鼠的收缩压均显著下降(P<0.01),且21时针刺组的收缩压明显低于14时针刺组(P<0.01)。治疗后,与本组治疗前相比,21时针刺组大鼠收缩压显著降低(P<0.01)。(2)与SHR模型组相比,14时针刺组与21时针刺组大鼠心肌组织Bmal1、Clock、Per2的mRNA表达水平均明显下调(P<0.05)。与14时针刺组相比,21时针刺组Clock、Per2的mRNA表达水平明显降低(P<0.05)。(3)与SHR模型组相比,14时针刺组与21时针刺组大鼠心肌组织Bmal1、Clock、Per2蛋白表达水平均明显下调(P<0.05)。21时针刺组Bmal1、Clock、Per2蛋白表达水平明显低于14时针刺组(P<0.01)。结论:仿真针刺能够降低SHR的收缩压,下调其心肌生物钟基因Bmal1、Clock、Per2的mRNA和蛋白表达水平,且21时仿真针刺的降压效果优于14时仿真针刺。

Objective: To discuss the effects of simulated acupuncture at different time points on systolic blood pressure and expressions of myocardial circadian clock genes in spontaneous hypertensive rats(SHR), including brain and muscle arnt-like protein 1(Bmal1)、circadian locomotor output cycles kaput(Clock) and period 2(Per2). Methods: Twenty-four male SHR were randomly divided into the SHR model group, acupuncture at 14:00 group and acupuncture at 21:00 group, 8 rats in each group. Another 7 male WKY rats were used as control. Bilateral Zusanli and Quchi acupoints were selected, with the aid of ATP-1 simulated acupuncture manipulation instrument, the rats in the acupuncture at 14:00 group and acupuncture at 21:00 group were treated with simulated acupuncture at the corresponding time points, once every other day for 10 times. The systolic blood pressure of tail artery was measured before and after treatment. After the last intervention, the myocardial tissue was isolated. The mRNA expressions of Bmal1, Clock and Per2 in the myocardial tissue were detected by PCR, and the protein expressions of Bmal1, Clock and Per2 were detected by Western blot. Results:(1)After treatment, compared with the SHR model group, the systolic blood pressure of rats in the acupuncture at 14:00 group and acupuncture at 21: 00 group was decreased significantly( P<0.01),and the systolic blood pressure of the acupuncture at 21: 00 group was significantly lower than that of the acupuncture at 14: 00 group( P < 0. 01). After treatment,compared with that before treatment,the systolic blood pressure of rats in the acupuncture at 21: 00 group was decreased significantly( P<0.01).(2)Compared with the SHR model group,the mRNA expression levels of Bmal1,Clock and Per2 in the myocardial tissue were significantly down-regulated in the acupuncture at 14: 00 group and acupuncture at 21: 00 group( P < 0. 05). The mRNA expression levels of Clock and Per2 in the acupuncture at 21: 00 group were significantly lower than those in the acupuncture at 14: 00 group( P<0.05).(3)Compared with the SHR model group,the protein expression levels of Bmal1,Clock and Per2 in the myocardial tissue were significantly down-regulated in the acupuncture at 14: 00 group and acupuncture at 21: 00 group( P<0.05). The protein expression levels of Bmal1,Clock and Per2 in the acupuncture at 21: 00 group were significantly lower than those in the acupuncture at 14: 00 group( P < 0.01). Conclusion: Simulated acupuncture can reduce the systolic blood pressure of SHR and down-regulate the mRNA and protein expression levels of Bmal1,Clock and Per2 in the myocardial tissue,and the antihypertensive effect of simulated acupuncture at 21: 00 is better than that of simulated acupuncture at 14: 00.