电刺激小脑顶核对心肌梗死大鼠心率变异性的作用

Effects of Fastigial Nucleus Electro-Stimulation on Heart Rate Variability in Myocardial Infarction Rats

目的观察预先电刺激小脑顶核(fastigial nuc leus stimu lation,FNS)对心肌梗死(myocard ial infarction,M I)大鼠心率变异性(heart rate variab ility,HRV)的作用。方法成年雄性W istar大鼠60只,随机分为:(1)M I组,结扎左冠状动脉前降支(left anterior descend ing artery,LAD);(2)预先电刺激小脑顶核1 h再予以左冠状动脉结扎组(FNS+M I组);(3)毁损小脑顶核(fastigial nuc leus lesion,FNL)5 d后电刺激小脑顶核1 h,再行左冠状动脉结扎组(FNL+FNS+M I组)。(4)假手术组(Sham组),开胸术后仅在LAD下穿线但不结扎,电极插入小脑顶核,但不予以刺激。各组又分开胸术后1、7、21 d 3个时间点,分别采用微机大鼠心率变异性记录分析系统进行心率变异性的频域分析和非线性分析。结果M I组与Sham组比较,频域分析指标-低频(low frequency,LF)、高频(h igh frequency,HF)、标准化的高频(norm alized h igh frequency,HFnorm)均显著降低(P<0.05或P<0.01),标准化的低频(norm al-ized low frequency,LFnorm)与LF/HF比值升高(P<0.01);非线性分析指标-分形维数(fractal d im ension,FD)明显降低(P<0.05或P<0.01)。FNS+M I组与M I组比较,M I后各时间点HRV参数HF、LF、HFnorm、FD等明显升高(P<0.05或P<0.01),而LFnorm、LF/HF降低(P<0.01)。FNL+FNS+M I组与M I组比较,HRV各参数无显著性差异(P>0.05)。结论电刺激小脑顶核可改善心肌梗死大鼠心率变异性。

Objective To investigate the effects of fastigial nucleus electro-stimulation（FNS） in advance on heart rate variability（HRV） in rats with myocardial infarction（MI）. Methods Sixty adult male Wistar rats were randomly divided into four groups： group MI was rats ligating the left anterior artery alone; group FNS ＋ MI was rats receiving FNS for 1 h before producing MI; group FNL ＋ FNS ＋ MI was rats undergoing the same procedure like group FNS ＋ MI except that there were lesions of the bilateral fastigial nucleus five days before producing MI; group Sham was rots mimicing all the operations as non-infarction control. Then every group was randomly divided into three subgroups according to three time points, that is 1,7,21 d after MI for further study. Frequency domain and nonlinear indexes were measured by the HRV recording and analyzing equipment. Results Compared to Sham group, the indexes decreased significantly for high frequency（HF）, low frequency（LF）, and normalized high frequency（HFnorm） as well as fractal dimension（FD） at matched time points in MI group（P〈0.05 or P〈0.01） ; while normalized low frequency（LFnorm） and LF/HF increased significantly （P 〈 0.05 or P 〈 0.01 ）. Compared to MI group, the indexes of HF, LF, HFnorm and FD increased significantly （P 〈 0.05 or P 〈 0.01 ）, LFnorm , LF/HF decreased significantly（ P 〈 0.01 ） ; but there was no significance for the changes of the above in FNL ＋ FNS ＋ MI group（ P 〉 0.05 ）. Conclusion Fastigial nucleus electro-stimulation can im- prove the heart rate variability in MI rats.