甘氨酸拮抗内毒素性心脏损伤的作用及机制研究

发布时间：2018-01-17 23:09

本文关键词：甘氨酸拮抗内毒素性心脏损伤的作用及机制研究　出处：《暨南大学》2007年硕士论文　论文类型：学位论文

【摘要】： 目的内毒素血症的死亡率仍具高不下，且内毒素血症患者一旦并发心功能损伤，其死亡率将大大提高，但是目前临床上尚未找到行之有效的药物。本室多年的研究证实甘氨酸(Gly)能有效拮抗内毒素(LPS)，并有心肌细胞保护作用。本研究拟在上述研究的基础上，在体研究预防性给予Gly能否拮抗LPS诱导的大鼠心脏损伤，并进一步探讨其保护机制，，为临床内毒素血症的防治提供理论依据。方法研究分为2个部分进行。 1．Gly对LPS导致的大鼠心脏损伤的影响。实验动物被随机分为5组，分别是NS组、LPS组、20％Gly+LPS组、10％Gly+LPS组、5％Gly+LPS，给予LPS或生理盐水4h后，各组取部分动物进行左心室插管，测定各组动物血流动力学的变化；全自动生化分析仪测定剩余动物血清中心肌酶(LDH、CK)活性的变化，并通过透射电镜观察动物心肌超微结构的变化，从三个方面判断LPS性心脏损伤模型制备是否成功，并观察Gly对LPS诱导的心脏损伤的影响。 2．探讨Gly拮抗LPS性心脏损伤的机制。运用ELISA法检测血清中和心肌组织中TNFα的含量；化学比色法检测心肌组织中caspase-3活力；TUNEL法测定各组动物的心肌细胞调亡率，从循环中和心肌细胞局部TNFα的表达量和心肌细胞凋亡方面探讨Gly拮抗LPS性心脏损伤的机制。结果 1．血流动力学分析结果显示：LPS组反映心脏收缩功能的左心室收缩压(LVSP)和左心室内压最大上升速率(+dp／dtmax)降低，反映心脏舒张功能的左心室终末舒张压(LVEDP)和左心室内压最大下降速率(-dp／dtmax)升高，与NS组比较差异有显著性(P＜0.01)，Gly防治组上述指标优于LPS组，其中10％Gly+LPS组LVEDP、+dp／dtmax与LPS组比较差异有显著性(P＜0.05)；LPS组LDH、CK活力升高，与NS组比较差异有显著性(P＜0.05)，所有Gly防治组LDH活力与LPS组比明显降低(P＜0.05)；透射电镜下观察，LPS组心肌纤维断裂溶解，心肌细胞核染色质边集、细胞核皱缩、核碎裂，线粒体肿胀、部分线粒体空泡化，Gly防治组心肌细胞超微结构损伤有明显改善。 2．LPS组血清和心肌组织中TNFα表达量较NS组明显升高(P＜0.01)，10％Gly+LPS组和5％Gly+LPS组血清中的TNFα含量低于LPS组(P＜0.01)，10％Gly+LPS组和5％Gly+LPS组中心肌细胞中的TNFα含量亦低于LPS组(P＜0.05)；LPS组心肌细胞的caspase-3活力较NS组明显升高(P＜0.01)，10％Gly+LPS和5％Gly+LPS组心肌细胞的caspase-3活力降低，与LPS组比较差异有显著性(P＜0.05)；TUNEL法显示LPS组有大量心肌细胞凋亡，Gly防治组心肌细胞的调亡率降低，其中10％Gly+LPS组和20％Gly+LPS组心肌细胞的调亡率与LPS组比较有显著性差异(P＜0.01)，5％Gly+LPS组心肌细胞的调亡率与LPS组比较差异有显著性(P＜0.05)。结论 1．Gly可改善血流动力学指标，减轻在体状态下LPS所致的大鼠心功能障碍。 2．Gly能抑制LPS诱发的心肌酶(LDH)释放。 3．Gly可抑制LPS所致的心肌细胞超微结构损伤，发挥心脏保护作用。 4．Gly拮抗LPS性心脏损伤的机制可能与抑制髓样细胞和心肌细胞分泌TNFα、抑制心肌细胞中caspase-3活化、减少心肌细胞凋亡的发生有关。
[Abstract]:objective
The mortality rate of endotoxemia is still high, and once the heart function of patients with endotoxemia complicated with injury, the mortality rate will be greatly improved, but the current clinical drug research has not been found effective. The room for the glycine (Gly) can effectively antagonize endotoxin (LPS), and the protective effect of myocardial cells in this study. On the basis of the above study, the prophylactic administration of Gly can antagonize LPS induced cardiac injury in rats in vivo, and to further explore the protective mechanism, to provide theoretical basis for clinical prevention and treatment of endotoxemia.
Method
The study is divided into 2 parts.
1.Gly on LPS induced rat cardiac injury. The effects of the experimental animal were randomly divided into 5 groups, namely NS group, LPS group, 20%Gly+LPS group, 10%Gly+LPS group, 5%Gly+LPS, LPS or saline 4h, each group to take part in animal left ventricular intubation, changes of hemodynamics were measured animal; Determination of residual animal serum myocardial enzyme automatic biochemical analyzer (LDH, CK) activity changes, and changes of animal myocardial ultrastructure was observed by transmission electron microscope, from three aspects to judge LPS heart injury model preparation is successful, and the effect of Gly on cardiac injury induced by LPS.
2. to investigate the mechanism of Gly against LPS injury of heart. The content of TNF alpha ELISA for detecting serum and myocardial tissues; the activity of Caspase-3 in myocardial tissue were detected by chemical colorimetry; myocardial cell was measured by TUNEL animal death rate, to explore the mechanism of Gly against LPS injury of heart from the expression and apoptosis of myocardial cells the circulation and myocardial cells in local TNF alpha.
Result
1. hemodynamic analysis showed that left ventricular systolic function in LPS group reflected pressure (LVSP) and left ventricular pressure maximal rate of rise (+dp / dtmax) decreased, reflecting the left ventricular diastolic function end diastolic pressure (LVEDP) and left ventricular pressure maximal rate of decrease (-dp / dtmax)., there was significant difference compared with NS group (P < 0.01), Gly control group the index is better than that of LPS group, 10%Gly+LPS group LVEDP, there were significant differences in +dp / dtmax and LPS group (P < 0.05); group LPS, LDH, CK activity increased, compared with the NS group had significantly difference (P < 0.05), all Gly control group and LPS group than the LDH activity decreased significantly (P < 0.05); transmission electron microscope, LPS group myocardial fibers dissolved, myocardial nuclear chromatin, cell shrinkage, nuclear fragmentation, mitochondrial swelling, mitochondrial vacuolization, Gly prevention and treatment of myocardial ultrastructure. The damage of structure is obviously improved.
The amount of TNF alpha were significantly higher than the NS group the expression of 2.LPS in serum and myocardium (P < 0.01), TNF 10%Gly+LPS group and 5%Gly+LPS group alpha content in serum was lower than that of LPS group (P < 0.01), TNF were 10%Gly+LPS group and 5%Gly+LPS group of myocardial cells in the lower than that of group LPS (P < 0.05) LPS; group of myocardial cell caspase-3 activity was higher than that of group NS (P < 0.01), 10%Gly+LPS and 5%Gly+LPS group of myocardial cell caspase-3 activity decreased, there was significant difference compared with LPS group (P < 0.05); TUNEL showed that LPS group had a large number of myocardial cell apoptosis, Gly control group myocardial cell apoptosis rate decreased in the 10%Gly+LPS group and the 20%Gly+LPS group of myocardial cell apoptosis rate and LPS groups had significant difference (P < 0.01), there was significant difference between 5%Gly+LPS group myocardial cell apoptosis rate and LPS group (P < 0.05).
conclusion
1.Gly can improve the hemodynamic index and reduce the cardiac dysfunction in rats induced by LPS in body state.
2.Gly can inhibit the release of myocardial enzymes (LDH) induced by LPS.
3.Gly can inhibit the ultrastructural damage of myocardial cells induced by LPS and play a protective role in the heart.
The mechanism of 4.Gly antagonizing LPS induced cardiac injury may be related to inhibiting the secretion of TNF alpha by medullary cells and cardiomyocytes, inhibiting the activation of Caspase-3 in cardiomyocytes, and decreasing the apoptosis of cardiomyocytes.

【学位授予单位】：暨南大学
【学位级别】：硕士
【学位授予年份】：2007
【分类号】：R363

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