电刺激大鼠岛叶对心率变异性的影响

发布时间：2018-01-11 21:29

本文关键词：电刺激大鼠岛叶对心率变异性的影响　出处：《中国医科大学》2008年硕士论文　论文类型：学位论文

【摘要】： 前言在窦性心律的一定时间内,这种逐次心动周期之间的时间变异数即为心率变异性(heart rate variability,HRV)。产生心率波动的因素非常复杂,包括脑的高级神经活动、中枢神经系统的自发性节律活动、呼吸活动以及由压力、化学感受器导入的心血管反射活动等。临床医学还证明:急性心肌梗塞、心脏病患者的猝死、充血性心衰、高血压、冠心病等心血管疾病,甚至糖尿病患者的HRV都较正常人有显著的降低。由此可见,HRV的研究对心血管疾病的早期诊断、病中监护及预后评估有重要意义。岛叶是控制交感神经和副交感神经介导的心血管调节最重要的皮层区域,岛叶损伤会引起一系列心率变异性参数的变化,包括SDNN,RMSSD降低,LF/HF升高以及夜间平均心率明显增加,血清去甲肾上腺素水平升高和QT间期延长以及复杂的心律失常,甚至猝死。这些现象均说明岛叶损伤可以引起交感—迷走神经平衡失调,进而出现病理性交感神经激活。预适应现象(Preconditioning,PC)是指机体或者组织预先受到轻微的刺激或者损伤后,对后期较强的刺激或损伤产生耐受的现象。预适应原理可以使我们针对不同的应激采用合适的措施来提高自身对应激的适应性,以防范应激产生的伤害效应。本实验通过观察岛叶接受电刺激及预刺激后大鼠HRV的改变及其频谱成份的变化,来判断电刺激及预刺激在大鼠HRV调节中的作用。实验方法健康雄性Wistar大鼠40只,体重250—300g,由中国医科大学实验动物中心提供。在实验前三天将大鼠置于一避音房间,给予12h:12h光照—黑暗周期(早8:00—20:00光照),保持室温24±2℃,湿度(55±5)%。大鼠单笼饲养,自由进食、水,在实验中随机分组。测量心电图前三天让大鼠在实验室适应1—2小时。随机抽取10只大鼠,采用针形电极给予500μA电流20分钟,作为500μA组。随机抽取10只大鼠,采用针形电极给予1000μA电流20分钟,作为1000μA组。随机抽取10只大鼠,在给予1000μA电刺激前,给予50μA电流20分钟,作为预刺激组。随机抽取10只大鼠采用上述方法插入电极,但是不通电流,作为假手术对照组。然后分别测量各组ECG,用随机附带的分析软件分析HRV,得到HRV各指标的数据。数据用SPSS软件处理。实验结果 500μA组同假手术组相比较HRV时域指标中SDNN(P＜0.05);RMSSD(P＞0.05)下降;频域指标中TP(P＜0.05)下降;而LF/HF升高(P＜0.01)。1000μA组同假手术组相比较HRV时域指标中SDNN(P＜0.05),RMSSD(P＞0.05)下降;频域指标中TP(P＜0.05)下降;而LF/HF升高(P＜0.01)。预刺激组SDNN(P＜0.01),RMSSD(P＜0.05),TP(P＜0.05),LF/HF(P＞0.05)均升高,且LF/HF升高幅度不及1000μA刺激组,提示预刺激可以削弱电刺激岛叶造成的交感神经活性升高。结论 1、电刺激岛叶使大鼠HRV时域指标中SDNN、RMSSD下降;频域指标TP下降,但是LF/HF升高,而且这种变化是可逆的。 2、电刺激岛叶可通过作用于自主神经系统,增加交感神经张力,降低迷走神经张力,使交感和迷走神经功能失调而使HRV降低。 3、预刺激可以减轻电刺激对HRV的影响,并且使HRV参数值较快恢复正常。
[Abstract]:Preface
In a certain period of time to sinus rhythm within the time period between successive cardiac number variation is the heart rate variability (heart rate, variability, HRV). The factors causing the fluctuation of heart rate is very complex, including senior neural activity of the brain, spontaneous rhythm of central nervous system activity, breathing activity and by pressure chemoreceptor the cardiovascular reflex activities. Clinical medicine has proved that acute myocardial infarction and sudden death in patients with heart disease, hypertension, congestive heart failure, coronary heart disease and other cardiovascular diseases, even in patients with diabetes compared with normal HRV were significantly reduced. Therefore, the early diagnosis of cardiovascular disease in HRV research, it is important to evaluate the monitoring and the prognosis of disease.
The insula is control of sympathetic and parasympathetic nerve mediated cardiovascular regulating cortical regions most important changes, the insular injury can cause a series of HRV parameters including SDNN, RMSSD decreased, LF/HF increased and nocturnal mean heart rate increased significantly, serum norepinephrine epinephrine levels and prolonged QT interval and complex arrhythmias, or sudden death. These phenomena explain that insular damage may be caused by sympathetic and vagal imbalance, and pathological sympathetic activation. Preconditioning (Preconditioning, PC) refers to the body or organization in advance by the slight stimulation or injury, produce the phenomenon of tolerance to strong stimulation or late injury. Principle of preconditioning can make us different stress to adopt appropriate measures to improve their adaptability to stress, in order to prevent stress damage caused by the effect. The effect of electrical stimulation and pre stimulation on the regulation of HRV in rats was observed by observing the changes of HRV and the changes of spectral components in rats after receiving electrical stimulation and pre stimulation.
Experimental method
40 healthy male Wistar rats, weighing 250 300g, provided by the experimental animal center of China Medical University. On the three day before the experiment the rats were placed in a room to avoid sound, light dark cycle (12h:12h - 8:00 - 20:00 back light), keep the room temperature 24 - 2 DEG C, humidity (55 + 5)%. Rats were reared in single cage, free food, water, were randomly divided into two groups in the experiment. Three days before the ECG let the rats adapt to 1 - 2 hours in the laboratory.
10 rats were randomly selected using needle electrode for 500 A current for 20 minutes, as the 500 A group. 10 rats were randomly selected using needle electrode for 1000 A current for 20 minutes, as the 1000 A group. 10 rats were randomly selected in the given 1000 A electrical stimulation before giving 50 A current for 20 minutes, as the pre stimulation group. 10 rats were randomly selected by the method of insertion of the electrode, but no current, as sham control group were measured respectively. Then ECG analysis, HRV analysis software to use the attached HRV, get the index data. The data with SPSS software. Daniel.
experimental result
500 A group compared with the sham operation group SDNN HRV time domain index (P < 0.05); RMSSD (P > 0.05) decreased; in the frequency domain index TP (P < 0.05) decreased; while LF/HF increased (P < 0.01).1000 A group compared with the sham operation group (SDNN HRV time domain index P < 0.05), RMSSD (P > 0.05) decreased; in the frequency domain index TP (P < 0.05) decreased; while LF/HF increased (P < 0.01). Pre stimulation group SDNN (P < 0.01), RMSSD (P < 0.05), TP (P < 0.05), LF/HF (P > 0.05) are increased, and LF/HF increased less than 1000 mu A stimulation group, suggesting that pre stimulation to weaken the electrical activity of sympathetic nerve stimulation caused by the elevation of the insular.
conclusion
1, the electrical stimulation of the island leaves decreased the SDNN and RMSSD in the HRV time domain of rats, and the frequency domain index TP decreased, but the LF/HF increased, and the change was reversible.
2, electrical stimulation of insular lobe can increase sympathetic nerve tension, decrease vagus nerve tension and decrease sympathetic nerve and vagus nerve dysfunction by acting on the autonomic nervous system. HRV can also decrease the function of sympathetic nerve and vagus nerve.
3, pre stimulation can reduce the effect of electrical stimulation on HRV and restore the HRV parameters to normal.

【学位授予单位】：中国医科大学
【学位级别】：硕士
【学位授予年份】：2008
【分类号】：R331.38

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