急性低氧对大鼠胃组织细胞端粒长度的影响及其机制研究

发布时间：2018-06-29 23:30

本文选题：低氧 + 端粒　；参考：《青海大学》2017年硕士论文

【摘要】：目的:通过检测急性低氧环境下大鼠胃组织细胞端粒长度及TERT(端粒酶逆转录酶,Telomerase reverse transcriptase)、HIF-1a(低氧诱导因子1α,Hypoxia-inducible factor 1α)、HIF-2a(低氧诱导因子2α,Hypoxia-inducible factor2α)、ROS(活性氧自由基,reactive oxygen species)表达水平,观察急性低氧环境下大鼠胃组织细胞端粒长度的变化,并探讨其具体机制。方法:(1)选择雄性Wistar大鼠40只,随机分为对照组(n=10,兰州,1500米)与实验组(n=30,低压氧舱,5000米),实验组根据低氧暴露时间不同,分为低氧1d、3d、7d三组,每组各10只,取各组大鼠胃组织,行HE染色并在显微镜下观察胃组织细胞大体形态结构变化;(2)提取各组大鼠胃组织细胞DNA,采用Real-time PCR法测其端粒长度;(3)提取各组大鼠胃组织细胞总RNA及蛋白,采用Real-time PCR及Elisa法分别测其TERT、HIF-1α及HIF-2αm RNA及蛋白表达水平;(4)制备各组大鼠胃组织匀浆液,采用化学荧光法测其ROS水平;(5)分析各组大鼠胃组织细胞TERT、HIF-1α、HIF-2α及ROS水平在其端粒长度变化中的作用,并行相关性分析。结果:(1)在低压氧舱中模拟5000m高海拔(严重低氧环境)构建出高原严重低氧对大鼠胃组织细胞的损伤模型,其病理结果显示随着低氧时间的逐渐延长,胃黏膜损伤逐渐加重,主要表现为胃黏膜腺体逐渐萎缩,黏膜充血,大量炎细胞浸润,细胞发生嗜酸性变;(2)与对照组相比,各时间点实验组端粒长度均延长(P0.05),并且随着低氧时间的延长,端粒长度表现为逐渐增加的趋势;(3)各组TERT、HIF-1αm RNA及蛋白表达水平的变化趋势与其端粒长度的变化趋势基本一致,但其HIF-2αm RNA及蛋白表达水平未见这一变化趋势,仅在低氧7天组表达增加;(4)实验组ROS表达量与对照组相比均增加(P0.05),并且随着低氧时间的延长,ROS表达量逐渐升高;(5)大鼠胃组织细胞中TERT与HIF-1α的蛋白表达水平呈正相关(r=0.839 p0.05),而TERT与HIF-2α蛋白表达水平无相关性(r=0.298 p=0.062);(6)大鼠胃组织细胞中TERT与HIF-1αm RNA表达水平呈正相关(r=0.904 p0.05);TERT m RNA表达水平与端粒长度呈正相关(r=0.962 p0.05),而TERT与HIF-2αm RNA表达无相关性(r=0.298 p=0.248)。结论:(1)急性严重高原低氧环境可使机体ROS表达增加,进而导致大鼠胃组织细胞损伤;(2)急性严重高原低氧环境可诱导大鼠胃组织细胞端粒延长,并且端粒的长度随着低氧时间的延长而延长,且与TERT与HIF-1α表达呈正相关,而与HIF-2α表达无明显相关,由此考虑急性高原严重低氧引起端粒延长的机制为:大鼠胃组织细胞HIF-1α表达水平升高,诱导TERT表达及端粒酶活性增加,来延长端粒;(3)急性严重高原低氧环境下,大鼠胃组织细胞可以通过延长端粒,来对抗低氧对其的损害,不致于使其发生严重的致命性损伤。
[Abstract]:Objective: to detect the length of telomere and the expression of reactive oxygen species) (reactive oxygen species) of reactive oxygen free radical) in gastric tissue cells of rats exposed to acute hypoxia, and to detect the expression of HIF-2a (Hypoxia-inducible factor 1 伪) and telomerase reverse transcriptase (reverse transcriptase) HIF-1a (hypoxia inducible factor 1 伪). To observe the changes of telomere length in gastric tissue of rats under acute hypoxia and to explore its mechanism. Methods: (1) Forty male Wistar rats were randomly divided into control group (n = 10, Lanzhou 1500m) and experimental group (n = 30, hypobaric oxygen chamber, 5000m). According to the time of hypoxia exposure, the experimental group was divided into three groups with 10 rats in each group. He staining was performed and observed under microscope. (2) DNA of gastric tissue cells was extracted from each group and telomere length was measured by Real-time PCR. (3) Total RNA and protein of gastric tissue cells were extracted from each group. Real-time PCR and Elisa were used to detect the mRNA and protein expression levels of TERTHIF-1 伪 and HIF-2 伪, respectively. (4) the gastric tissue homogenate of rats in each group was prepared. (5) the role of TERTHIF-1 伪 HIF-2 伪 and Ros in telomere length was analyzed. Results: (1) the model of gastric tissue cells injury induced by severe hypoxia at altitude of 5000m was established in the hypobaric oxygen chamber. The pathological results showed that the gastric mucosal injury was aggravated with the prolongation of hypoxia time. The main manifestations of gastric mucosal gland atrophy, mucosal congestion, a large number of inflammatory cells infiltration, eosinophilic cells; (2) compared with the control group, the telomere length of the experimental group was prolonged at each time point (P0.05), and with the prolongation of hypoxic time, Telomere length showed a tendency of increasing gradually. (3) the change trend of telomere length was basically the same as that of telomere length, but the expression level of HIF-2 伪 mRNA and protein was not. (4) the expression of Ros in the experimental group was higher than that in the control group (P0.05), and gradually increased with the prolongation of hypoxia time. (5) the expression level of TERT and HIF-1 伪 protein in gastric tissue cells of rats was positive. The expression level of TERT and HIF-1 伪 mRNA was positively correlated with telomere length (r 0.962 p0.05) in rat gastric tissue cells (r 0.298pn 0.062); (6), while TERT was not correlated with HIF-2 伪 mRNA expression (r 0.298pt0. 248) in rat gastric tissue cells (r = 0.904 p0.05), while TERT was not correlated with HIF-2 伪 mRNA expression (r = 0.298pt0. 248). The expression of TERT mRNA was positively correlated with telomere length (rr 0.962 p0.05), but not between TERT and HIF-2 伪 mRNA expression (r = 0.298p0. 248). Conclusion: (1) acute severe high altitude hypoxia can increase the expression of Ros and induce gastric tissue cell injury in rats, (2) acute severe high altitude hypoxia can induce telomere prolongation in gastric tissue of rats. The length of telomere increased with the prolongation of hypoxia time, and was positively correlated with the expression of TERT and HIF-1 伪, but not with the expression of HIF-2 伪. Therefore, the mechanism of telomere prolongation caused by severe hypoxia at high altitude is as follows: the expression of HIF-1 伪 in rat gastric tissue cells is increased, and the expression of TERT and telomerase activity are increased to prolong telomere; (3) in acute severe hypoxia environment, the expression of TERT and telomerase activity are increased in order to prolong telomere. Rat gastric tissue cells can prolong telomeres to prevent hypoxia from causing severe and fatal damage.
【学位授予单位】：青海大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R594.3

【相似文献】