劳力性热射病大鼠线粒体损伤机制及红景天苷的保护作用研究

发布时间：2018-04-05 11:10

  本文选题：劳力性热射病　切入点：热应激反应　出处：《第二军医大学》2016年博士论文

【摘要】：劳力性热射病(Exertional Heat Stroke,EHS)是在高温高湿环境下强体力训练、施工时发生的严重中暑,表现为高热、昏迷、抽搐、横纹肌溶解,多并发多脏器功能衰竭,如果延误治疗,该病的致死率高达50-70%以上。劳力性热射病的发生除了高温伤害以外,还与长时间的高强度体能运动导致机体重要脏器相对缺血、缺氧有关。无论高温还是缺氧都将损害线粒体功能,加剧机体的缺氧,使病情进一步恶化。及时保护线粒体功能有助于减轻EHS对机体的伤害。线粒体作为机体有氧呼吸和氧化磷酸化产能的细胞器。当全身出现急性缺血缺氧性损伤时,线粒体的结构和功能也有可能损害。大株红景天的主要成分为红景天苷,能够抑制缺氧、低糖致伤的线粒体损伤,减少细胞凋亡的发生,已被广泛应用于改善心肌急慢性缺氧、缺血性损伤。因此在理论上复合两种损伤的劳力性热射病一定会出现线粒体结构和功能的损害,造成后续组织器官能量代谢障碍。这或许是劳力性热射病时出现一系列病理生理改变的关键环节之一。因此本课题拟分析劳力性热射病时机体组织细胞线粒体损伤特点以及探讨红景天苷对线粒体的保护作用。本课题以劳力性热射病大鼠模型为研究对像,比较分析不同条件下各组大鼠线粒体相关指标的检测结果,获得相关环境参数以及模型动物的临床表现和各检测指标的变化,得到劳力性热射病线粒体结构、功能损伤特点及分子机制;并进一步利用劳力性热射病大鼠模型,比较分析劳力性热射病大鼠和红景天苷不同剂量组大鼠的各相关检测指标,探索红景天苷对劳力性热射病线粒体结构、功能损伤的保护作用及其可能的机制。第一部分劳力性热射病大鼠动物模型及线粒体损伤特点目的:建立稳定的劳力性热射病大鼠动物模型,并研究线粒体结构、功能损害特点。方法:40只SD大鼠,随机分4组,每组10只:(A)对照组、(B)常温力竭组、(C)高温组,即非劳力性热射病组、(D)劳力性热射病组。其中A组大鼠常规方法饲养;B组大鼠在温度22℃饲养,迫使其在实验动物跑台进行跑步运动(速度恒定为15m/min)。当大鼠停下是即给予电击(电压100V),直到大鼠力竭。C组大鼠放置于温度45℃条件下,不迫使大鼠运动,直到大鼠出现热射病表现。D组大鼠在温度45℃,湿度70%±5%的环境下给予同B组同样的运动处理方式。结合对照组,对比分析各组的线粒体结构和功能损伤的特点,包括线粒体膜电位(MMP),呼吸控制率(RCR),氧自由基(ROS),Ca2+,戊二醛(MDA)和超氧化物歧化酶(SOD)活性和PGC-1αm RNA以及Mn SOD m RNA等的变化情况。结果:1.在环境温度45℃,湿度70%±5%条件下,给予15m/min速度持续奔跑,可以构建劳力性热射病大鼠模型。2.电镜显示劳力性热射病组大鼠心、肝细胞和线粒体损伤表现为心肌和肝脏细胞显著肿胀,细胞膜碎裂,细胞器散落,线粒体表现为肿胀,甚至出现空泡改变,内部基质密度不均匀,内腔明显扩张,嵴断裂。3.劳力性热射病大鼠心、肝线粒体膜电位、呼吸控制率、离子钙浓度、SOD浓度显著低于对照组(0.05),ROS和MDA显著高于对照组(0.05),(PGC-lα)m RNA以及Mn SOD m RNA表达低于对照组。结论:劳力性热射病时细胞与线粒体结构首先受损,并出现膜电位、呼吸控制率、离子钙、SOD下降,氧自由基蓄积,MDA升高和(PGC-lα)m RNA以及Mn SOD m RNA表达下降等功能损伤。第二部分红景天苷对劳力性热射病大鼠线粒体的保护作用目的:探讨红景天苷对劳力性热射病大鼠线粒体的保护作用机制。方法:50只SD大鼠随机分为5组,分别为常温饲养红景天苷组(A组)、常规饲养劳力性热射病组(B组)、红景天苷低剂量组(L,4 mg/kg,C组)、中剂量组(M,10mg/kg,D组)、高剂量组(H,25 mg/kg,E组)。B、C、D、E组的劳力性热射病动物模型参照第一部分介绍的方法构建。对比分析不同剂量红景天苷饲养的劳力性热射病组大鼠与其余2组的运动距离、时间以及线粒体结构与功能指标,包括粒体膜电位(MMP),呼吸控制率(RCR),氧自由基(ROS),Ca2+,戊二醛(MDA)和超氧化物歧化酶(SOD)活性和PGC-1αm RNA以及Mn SOD m RNA表达水平。结果:高剂量红景天苷组的劳力性热射病大鼠线粒体结构与功能损伤程度低于常规饲养劳力性热射病组。表现为线粒体膜电位、呼吸控制率、离子钙浓度、SOD浓度显著高于常规饲养劳力性热射病组大鼠。ROS和MDA显著低于对照组,PGC-lαm RNA以及Mn SOD m RNA表达高于对照组。结论:高剂量的红景天苷通过稳定劳力性热射病大鼠线粒体的膜电位、呼吸控制率、离子钙浓度、SOD浓度并清除ROS和MDA并通过提高PGC-lαm RNA以及Mn SOD m RNA表达水平发挥保护作用。
[Abstract]:Exertional heat stroke (Exertional Heat, Stroke, EHS) is a strong physical training in high temperature and high humidity environment, severe heat stroke occurred during the construction of the performance for the high fever, coma, convulsions, rhabdomyolysis, more complicated with multiple organ failure, if the delay in treatment, the disease mortality rate as high as 50-70% exertional above. Heat stroke in addition to the occurrence of high temperature damage, and high intensity of physical exercise for a long time due to the important organs relative ischemia, hypoxia or hypoxia. Both high temperature will damage the function of mitochondria, increased body hypoxia, which worsens the situation. Timely protection of mitochondrial function is helpful to reduce the damage to the body. Mitochondrial EHS as the body cell respiration and oxidative phosphorylation capacity. When the body in the acute hypoxic ischemic injury, the structure and function of mitochondria may also damage. The main component of the large red Sedum plant As salidroside can inhibit hypoxia, mitochondrial damage, low sugar injury, apoptosis, has been widely used in acute and chronic hypoxic ischemic myocardial injury. Therefore, exertional heat stroke in the composite theory of two kinds of damage will appear to impair mitochondrial structure and function, causing the subsequent organization organ of energy metabolism disorder. This is probably one of the key links in a series of pathophysiological changes in the emergence of exertional heat stroke. Therefore this paper analysis of exertional heat stroke when the body tissue mitochondrial damage characteristics and to investigate the protective effect of red Sedum glycosides on mitochondria. The model of exertional heat stroke in rats in order to study the like, comparative analysis of results in detection of mitochondrial related indicators of rats under different conditions, obtain the relevant environmental parameters and animal models and clinical manifestations of all parameters change And get the exertional heat stroke mitochondrial structure, functional characteristics and molecular mechanism of injury; and further use of exertional heat stroke rat model, comparative analysis of exertional heat stroke rats and Salidroside in different dose group rats all relevant indexes, to explore the effect of salidroside on exertional heat stroke mitochondrial structure, protection function injury and its possible mechanism. The first part of exertional heat stroke rat animal model and the characteristics of Mitochondrial Injury Objective: to establish a rat animal model of stable exertional heat stroke, and to study the mitochondrial structure, function characteristics. Methods: 40 SD rats were randomly divided into 4 groups, each group 10: (A) control group, (B) at contrastingexhaustion group (C), the high temperature group, namely non exertional heat stroke group (D), exertional heat stroke group. The rats in the A group of conventional breeding methods; the rats in group B at a temperature of 22 DEG C 027, forcing it to in the experimental animal ran into Taiwan 琛岃窇姝ヨ繍鍔，

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