小脑顶核电刺激对心肌梗死大鼠心肌细胞内钙超载的影响

 研究预先电刺激小脑顶核(Fastigial Nucleus Stimulation,FNS)对心肌梗死(Myocardial Infarction,MI)大鼠心肌细胞钙超载的干预作用。将SD大鼠90只,随机分为3组,每组30只：MI组,仅结扎左冠状动脉前降支(LAD);FNS组,预先FNS 1h再予以LAD结扎;小脑顶核毁损组,毁损小脑顶核5d后FNS 1h,再行LAD结扎;各组又分MI后1,7,21d 3个亚组。另取8只设为假手术组。LAD结扎1,7,21d后,摘取心脏,分离大鼠左室心肌细胞,激光扫描共聚焦显微镜下观察心肌细胞内钙含量变化。结果显示,LAD结扎1,7d后,与假手术组比较,MI组或小脑顶核毁损组大鼠心肌细胞内钙含量均明显增加(P<0.05);与MI组比较,FNS组大鼠心肌细胞内钙含量显著减少(P<0.05);小脑顶核毁损组与MI组心肌细胞钙含量比较差异无统计学意义(P>0.05)。LAD结扎21d后,各实验组大鼠心肌细胞内钙含量比较无统计学差异。因此认为,FNS可减少心肌梗死大鼠早期心肌细胞内钙含量,并可能通过抑制心肌细胞的钙超载减少MI后大鼠死亡率。

Effects of Fastigial Nucleus Electrical Stimulation on Calcium-overload in Myocardium of Rats after Myocardial Infarction

Exploring the effect of Fastigial Nucleus Stimulation (FNS) on intracellular calcium overload in rats after Myocardial Infarction (MI) is taken aim at. Ninety SD rats were randomly divided into three groups with 30 rats for each group, that is, MI group, FNS group, and fastigial nucleus lesion group. In the MI group, left anterior descending artery of rats was ligated. In the FNS group, rats were pretreated with fastigial nucleus electro-stimulation for 1h, and then left anterior descending artery was ligated. In the fastigial nucleus lesion group, rats were treated with fastigial nucleus electro-stimulation for 1h after their fastigial nucleus was damaged for 5d, and then left anterior descending artery was ligated. Each group was further divided into three subgroups according to the three time points of 1, 7, and 21d, respectively after the ligation of left anterior descending artery. Eight SD rats were chosen as the sham operation group． After 1, 7, and 21d with the ligation of left anterior descending artery, the left ventricular myocytes were isolated from rat hearts. The Ca²⁺ concentration was determined by using laser scanning confocal microscopy. The results indicate that the fluorescence intensity of the labeled intracellular Ca²⁺ in MI group and fastigial nucleus lesion group is significantly higher than that in sham-operated group at the day one and day seven after MI (P<0.05), however the intensity in FNS group was significantly lower than that in MI group (P<0.05). There is no significant difference in Ca²⁺ concentration between MI group and fastigial nucleus lesion group (P>0.05). At the day 21 after MI, there are no significant differences in Ca²⁺ concentration among these four groups. Therefore, it might be concluded that FNS could decrease the Ca²⁺ concentration in myocytes at an early stage after MI, and might control MI mortality by inhibiting intracellular Ca²⁺ overload.