急性心肌梗死大鼠心电图ST段的演变特点及甘蔗叶多糖的保护作用

发布时间：2019-05-19 23:23

【摘要】：目的：1.结扎大鼠冠状动脉左前降支(LAD)建立心肌梗死模型,观测大鼠心肌梗死发生后心电图ST段的演变过程,以探寻适当的ST段检测时间及导联；2.探讨甘蔗叶多糖的心肌保护作用及其机制,为甘蔗叶多糖的开发利用提供依据。 方法：健康SD大鼠70只,雄性,体重230-250g,随机分为甘蔗叶多糖组(多糖组)及模型对照组(对照组)。术前24h及术前30min,多糖组及对照组分别进行灌胃处理,多糖组灌入浓度为4mg/ml甘蔗叶多糖溶液,剂量为lml/100g大鼠体重,模型组灌入等量生理盐水,采用结扎大鼠LAD的方法建立急性心肌梗死模型,记录开胸前及术后1h内每间隔5min的肢、胸导联心电图,测量心电图各导联各时刻ST段的偏移幅度。于术后第24h、48h、72h、96h继续灌胃处理,浓度及剂量不变。末次灌胃30min后经颈动脉取血测量血清肌钙蛋白含量(cTnI),并注射氯化钾处死大鼠后,开胸取出大鼠心脏,切除结扎线以上组织,放入10%甲醛溶液固定、包埋、切片。采用免疫组化法检测血管内皮生长因子(VEGF)、CD34的表达,应用Image Pro-Plus6.0图像分析系统对免疫组化图像进行分析。 结果：1.对照组心电图演变过程：对照组42只大鼠术后有26只存活至实验终点,经病理HE染色证实20只出现心肌梗死。对照组在结扎LAD后1h内,与术前比较,Ⅰ、Ⅱ aVL、V2、V5导联在各时刻ST段均抬高(P0.000),aVF、V1导联术后各时刻心电图无明显变化,胸导联ST段抬高较肢导联明显。自术后15min起,Ⅰ导联的抬高值大于aVL导联(P0.05)；术后25min内,Ⅰ导联的抬高值大于Ⅱ导联,之后无明显差异；Ⅱ与aVL导联无明显差异,V2、V5导联无明显差异；术后1h内,ⅠI、aVL导联分别自术后50mmin、35min起ST段的偏移幅度均低于术后10min (P0.05),而在Ⅱ、V2、V5导联各观测时点间的ST段偏移值差异无统计学意义。2.组间心电图比较：术后1h内,多糖组各导联ST段抬高值总体上小于模型组(P0.05)；两组间每个时点比较,V2导联的各时刻两组间ST段偏移幅度均无差异,其他导联特别是肢导联,在某些时刻多糖组ST段抬高值低于模型对照组。3.血清cTnI含量：多糖组与对照组cTnI含量均升高,但与模型对照组比较,多糖组血清中cTnI较低(P0.05)。4.免疫组化染色：光镜下见VEGF蛋白在梗死区周围心肌细胞胞质内被染成棕黄色颗粒状,阳性反应强度用平均积分光密度(MIOD)表示,多糖组VEGF的平均光密度大于对照组(P0.05),即VEGF蛋白的含量高。采用CD34标记血管内皮细胞,光镜下可见内皮细胞胞浆着色为棕黄色,分布于梗死灶周围的心肌细胞细胞之间,对CD34标记的微血管进行微血管计数(MVC),与对照组比较,多糖组MVC增多(P0.05)。 结论：1.结扎大鼠LAD后1h内,ST段的演变表现在Ⅰ、aVL导联；采用心电图肢导联判断大鼠是否心梗死时,应在术后早期观测ST段的变；2.甘蔗叶多糖能改善心肌梗死大鼠心电图表现；3.甘蔗叶多糖可降低心肌梗死大鼠血清中cTnI含量,对心肌细胞有一定保护作用；4.甘蔗叶多糖能促进VEGF的表达及微血管的生成,促进侧枝循环的建立,对大鼠急性心肌梗死具有一定的保护作用。
[Abstract]:Objective:1. The model of myocardial infarction was established by ligation of the left anterior descending branch (LAD) of the coronary artery, and the evolution of the ST segment after myocardial infarction in rats was observed to find the appropriate ST segment detection time and lead;2. The function and mechanism of the myocardial protection of the sugarcane leaf polysaccharide were discussed, and the basis for the development and utilization of the sugarcane leaf polysaccharide was provided. Methods:70 male and 230-250g of healthy SD rats were randomly divided into two groups (group of polysaccharides) and control group (control group). The group was treated by intragastric administration for 24 h before and 30 min before operation, and the polysaccharide group and the control group were given intragastric administration respectively. The concentration of the polysaccharide group was 4 mg/ ml of the sugarcane leaf polysaccharide solution, the dosage was lml/100 g of the rat's body weight, the model group was injected with the same amount of normal saline, and the acute myocardial infarction was established by the method of ligation of the LAD in the rat. Model, record the limb of each interval of 5 minutes and the electrocardiogram of the chest lead, and measure the deviation of ST segment at each time of each lead of the electrocardiogram. Magnitude: Gavage, concentration and dosage were continued at 24 h,48 h,72 h, and 96 h after operation. the serum cardiac troponin content (cTnI) was measured by carotid blood sampling after 30 minutes of the last administration, and after the rats were killed by potassium chloride, the heart of the rat was taken out of the rat after injection of potassium chloride, the tissues above the ligation line were cut off, and the tissue was fixed and embedded in a 10% formaldehyde solution, The expression of vascular endothelial growth factor (VEGF) and CD34 was detected by immunohistochemical method, and the image was analyzed by Image Pro-Plus6.0 image analysis system. Analysis. Results:1. The evolution of the electrocardiogram in the control group:26 of the 42 rats in the control group survived to the end of the experiment. In the control group, the ST segment of the first, the second aVL, the V2 and the V5 leads were elevated at all time (P0.05), and the ST segment of the chest lead was higher than that of the control group after the ligation of the LAD for 1 hour. The elevation of the I-lead was higher than that of the aVL lead (P0.05). The elevation of the I-lead was greater than that of the II-lead in 25 minutes after the operation. There was no significant difference between the II and the aVL lead, and there was no significant difference between the two groups. The deviation of ST segment at 0 mmin and 35 min was lower than that of 10 min after operation (P0.05). 2. The ST-segment elevation of each lead in the group was less than that of the model group (P0.05). Don't be a limb lead. In some time, the ST segment elevation value of the polysaccharide group is lower than the model. In the control group, the content of cTnI in the serum of the group of the polysaccharide and the control group increased, but the cTnI in the serum of the polysaccharide group was lower than that of the control group (P0. (05).4. Immunohistochemistry staining: The expression of VEGF protein in the cytoplasm of the myocardial cells around the infarction area was stained with brown yellow particles under the light microscope, and the average integral optical density (MIOD) of the positive reaction intensity was higher than that of the control group (P0.05), that is, the VEGF egg. The content of white was high. CD34 was used to mark the vascular endothelial cells, and the cytoplasm of the endothelial cells was stained with brown-yellow cells under the light microscope. The microvessel count (MVC) of the CD34-labeled microvessel was compared with the control group, and the MVC of the group was increased (P 0.05) Conclusion:1. The evolution of ST segment in 1 h after the ligation of LAD in rats is shown in the 鈪，

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