兰州大学机构库 >第一临床医学院
交感神经兴奋和氧化应激在压力-应激致心肌损伤机制中的研究
Alternative TitleStudy on the Mechanism of Sympathetic Nerve Excitement and Oxidative Stress in Stress Induced Myocardial Injury
董星明
Subtype硕士
Thesis Advisor张锦
2021-05-25
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name医学硕士
Degree Discipline内科学
Keyword压力-应激 交感神经兴奋 氧化应激 能量代谢 细胞凋亡
Abstract目的随着社会的发展和进步,工作生活节奏加快,压力-应激状态引起的健康问题越来越普遍,由此导致猝死的发生率明显增加。本研究通过采用孤养结合3种不可预知应激的方法建立压力-应激大鼠模型,从交感神经兴奋性、氧化应激、能量代谢和细胞凋亡等角度出发,就压力-应激状态对大鼠心肌产生损伤的机制进行初步探究。 方法将80只雄性SD大鼠适应性饲养1周后根据体重和行为学评价结果随机分为对照组和模型组,再依据建模周期分别设置2周组、4周组、8周组和12周组,每组各10只。对照组正常饲养,保持生活习性规律,模型组采用孤养结合3种不可预知应激的方法建立心肌损伤大鼠模型。通过评价实验后体重、糖水偏好试验和旷场试验的结果作为实验模型建立效果的参考。实验结束后,麻醉大鼠,经腹主动脉采血并摘取心脏用于实验检测。选取部分左心室心肌组织制作石蜡切片,HE染色后进行组织形态学观察。将采集的大鼠动脉血清,应用ELISA法检测去甲肾上腺素浓度。选取部分心室肌组织,研磨制作10%的心肌组织匀浆,应用WST-1法测定SOD活力,TBA法测定MDA含量;应用磷钼酸比色法测定心肌组织ATP含量。采用免疫组化方法检测Apaf-1蛋白在不同压力-应激周期大鼠心肌组织中的表达水平。 结果1.体重和行为学评价结果:各模型组大鼠体重增长缓慢,明显低于同期对照组,差异具有统计学意义(P<0.001)。与对照组相比,自建模2周起,模型组大鼠糖水偏好率降低,差异具有统计学意义(P<0.001)。自建模4周起,模型组大鼠旷场试验活动评分降低,差异具有统计学意义(P<0.05)。随着建模时间的延长,模型组大鼠的体重、糖水偏好率和旷场试验活动评分与对照组相比差异更加明显。 2.组织形态学观察结果:光镜下观察HE染色的心肌组织,对照组可见心肌组织形态正常,结构清晰完整,心肌细胞呈短柱状、连接紧密,心肌纤维排列规则整齐,横纹清晰。自建模2周起,模型组可见心肌组织结构受损,随着建模时间的延长,心肌组织损伤程度加重,表现为组织结构模糊,细胞界限不清,组织间隙增大,心肌纤维排列疏松紊乱,部分纤维断裂,横纹消失。 3.血清去甲肾上腺素浓度测定结果:与对照组相比,建模2周时,模型组血清去甲肾上腺素浓度升高,差异具有统计学意义(P<0.05);自建模4周起,与同期对照组相比,模型组血清去甲肾上腺素浓度显著升高,差异具有统计学意义(P<0.001),随着建模时间的延长,这种差异更加显著。 4.心肌组织氧化应激指标测定结果:在建模2周和4周时,模型组心肌组织SOD活力与同期对照组相比降低,但差异无统计学意义(P>0.05);建模8周时,与对照组相比,模型组心肌组织SOD活力明显降低,差异具有统计学意义(P<0.05);建模12周时,模型组心肌组织SOD活力与对照组相比降低更加明显(P<0.001)。建模2周时,模型组心肌组织MDA含量与对照组相比无明显差异(P>0.05);自建模4周起,模型组心肌组织MDA含量升高,与对照组相比,差异具有统计学意义(P<0.05);至建模12周时,模型组心肌组织MDA含量升高更加明显(P<0.001)。 5.心肌组织ATP含量测定结果:建模2周和4周时,模型组心肌组织ATP含量降低,与同期对照组相比,差异无统计学意义(P>0.05);建模8周时,模型组心肌组织ATP含量与对照组相比明显降低,差异具有统计学意义(P<0.05);建模12周时,与对照组相比,模型组心肌组织ATP含量降低更加显著,差异具有统计学意义(P<0.001)。 6.心肌组织Apaf-1表达测定结果:建模2周时,模型组心肌组织Apaf-1表达水平与对照组相比略升高,但差异无统计学意义(P>0.05);建模4周时,与对照组相比,模型组心肌组织Apaf-1表达水平增加,差异具有统计学意义(P<0.05);随着建模时间的延长,建模8周和12周时,心肌组织Apaf-1表达水平明显增加,与同期对照组相比,差异具有统计学意义(P<0.001)。 结论压力-应激状态可以引起交感神经系统过度兴奋、血清去甲肾上腺素浓度增加,同时压力-应激状态引起心肌组织发生氧化应激,抗氧化物质SOD和过氧化产物MDA表达异常。在交感神经过度兴奋和氧化应激的共同作用下,心肌组织出现结构改变、能量代谢异常和细胞凋亡相关蛋白表达增加,最终造成心肌损伤。
Other AbstractObjectiveWith the development of society and the accelerated pace of work and life, health problems caused by stress are becoming more and more common, resulting in a significant increase in the incidence of sudden death. In this study, a rat model of stress state is established by isolate feed combined with 3 types of unpredictable stress. From the perspectives of sympathetic nerve excitement, oxidative stress, energy metabolism and cell apoptosis, the mechanism of stress on myocardial injury in rats is preliminarily explored. Methods80 male SD rats were adaptively reared for 1 week and then randomly divided into control group and model group according to the results of body weight and behavioral evaluation. According to the modeling time, 2-week group, 4-week group, 8-week group and 12-week group were set up respectively, with 10 rats in each group. The control groups were fed in normal conditions and maintained the regularity of life habits, while the model groups received isolate feed combined with 3 types of unpredictable stress. The results of body weight, sugar preference test and open field test were evaluated as a reference for the effect of the experimental model. After modeling, the rats were anesthetized, blood was collected from the abdominal aorta and the rat hearts were taken for experimental detection. Part of the left ventricular myocardial tissue was selected to make paraffin sections, and morphological changes were observed after HE staining. The concentration of norepinephrine in rat arterial serum was determined by ELISA. Take part of myocardium and grind it into 10% tissue homogenate. The SOD activity was determined by WST-1 method. The MDA in myocardial tissue was measured by TBA method. The ATP in myocardial tissue was measured by phosphomolybdic acid colorimetry. Immunohistochemistry was used to detect the expression level of Apaf-1 in myocardial tissue of rats in different stress groups. Results1. Weight and behavior evaluation results: The weight of the rats in the model group increased slowly, which was significantly lighter than that in the control group and the difference was statistically significant (P<0.001). Compared with the control group, sugar water preference rate in the model group decreased from second week, and the difference was statistically significant (P<0.001). From the fourth week, the scores of open field test in the model group decreased and the difference was statistically significant (P<0.05). With the extension of the modeling time, compared with the control group, the results of body weight, sugar water preference rate and scores of open field test in the model group were more different. 2. Histomorphological observation results: The myocardium stained with HE was observed under light microscope, the control group has no abnormal changes. It can be seen that the myocardial cells are short columnar, with clear and complete structure and close connection. The myocardial fibers are neatly arranged, and the cross striation are clear. From the second week of modeling, the model group showed that the myocardial structure was damaged. As the stress time increased, the degree of myocardial damage increased. It can be seen that the myocardial structure is blurred, the cell boundary is unclear, and the intercellular space is enlarged. The arrangement of myocardial fibers is loose and disordered, partly broken, and cross striation disappear. 3. Determination results of serum norepinephrine concentration: Compared with the control group, at the second week of modeling, the concentration of serum norepinephrine of the model group increased, and the difference was statistically significant (P<0.05). At the fourth week of modeling, the serum norepinephrine concentration of the model group was significantly higher than that of the control group, and the difference was statistically significant (P<0.001). As the modeling time increases, this difference becomes more significant. 4. Determination results of oxidative stress in myocardial tissue: At the second and fourth weeks of modeling, compared with the control group, the SOD activity of the model group was reduced, but the difference was not statistically significant (P>0.05). At the eighth week, the SOD activity of the model group was significantly reduced, and the difference was statistically significant compared with the control group (P<0.05). At the twelfth week, compared with the control group, the SOD activity decreased more significantly (P<0.001). At the second week of modeling, the MDA content of the model group had no significant changes compared with the control group (P>0.05). From the fourth week, the MDA content of the model group increased, and the difference was statistically significant compared with the control group (P<0.05). At the twelfth week, the MDA content of the model group increased more significantly (P<0.001). 5. Determination results of ATP content in myocardial tissue: At the second and fourth week of modeling, compared with the control group, the ATP content of the model group was lower, but the difference was not statistically significant (P>0.05). At the eighth week, the ATP content of the model group was significantly reduced, and the difference was statistically significant (P<0.05). At the twelfth week of modeling, the ATP content of the model group decreased more significantly than the control group, and the difference was statistically significant (P <0.001). 6. Determination results of Apaf-1 in myocardial tissue: At the second week of modeling, the expression of Apaf-1 in the model group was slightly higher than that of the control group, but the difference was not statistically significant (P>0.05). At the fourth week, the expression level of Apaf-1 in myocardial tissue of model group increased, and the difference was statistically significant (P<0.05). With the extension of the modeling time, at the eighth and twelfth weeks the expression level of Apaf-1 in myocardial tissue increasedsignificantly, and the difference was statistically significant compared with the control group (P <0.001). ConclusionsStress can cause overexcitement of the sympathetic nervous system and increase the serum norepinephrine concentration. At the same time, oxidative stress occurred in myocardial tissue, and the expression of SOD and MDA was abnormal. Under the influence of sympathetic nervous system overexcitement and oxidative stress, the myocardial tissue showed structural changes, abnormal energy metabolism, and increased expression of apoptosis-related proteins, which led to myocardial injury.
Pages52
URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/462488
Collection第一临床医学院
Affiliation
第一临床医学院
First Author AffilicationFirst Clinical School
Recommended Citation
GB/T 7714
董星明. 交感神经兴奋和氧化应激在压力-应激致心肌损伤机制中的研究[D]. 兰州. 兰州大学,2021.
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