Expression of hypoxia inducible factor-1 alpha and ischemic erythropoietin tolerance in the brain of cerebral ischemic tolerance model rats

BACKGROUND： Hypoxia inducible factor-1 alpha （HIF-1 （x） and erythropoietin（EPO）, possessing neuroprotective effect in the cerebral ischemia, might play an important role in the formation of cerebral ischemic tolerance （IT）. OBJECTIVE：To observe the neuroprotective effect of cerebral ischemic preconditioning（IPC） of rats, and the expression and mechanism of HIF-1α and target gene erythropoietin in the brain tissue following the formation of cerebral IT. DESIGN ： A randomized and controlled observation SETTING： Department of Neurology, the Affiliated Hospital of Medical College, Qingdao University MATERIALS： Totally 84 enrolled adult healthy male Wistar rats of clean grade, weighing 250 to 300 g, were provided by the Animal Experimental Department, Tongji Medical College of Huazhong University of Science and Technology. Ready-to-use SABC reagent kit and rabbit anti-rat HIF-1α monoclonal antibody were purchased from Boshide Bioengineering Co.Ltd （Wuhan）; Rabbit anti-rat EPO monoclonal antibody was purchased from Santa Cruz Company （USA）. METHODS： This experiment was carried out in the Department of Anatomy, Medical College, Qingdao University during March 2005 to March 2006. ① The 84 rats were divided into 3 groups by a lot： IPC group （n=40）, sham-operation group （n=40） and control group （n=4）. In the IPC group, middle cerebral artery was occluded for 2 hours respectively on the 1^st, 3^rd, 7^th, 14^th and 21^st days of the reperfusion following 10-minute preischemia was made using a modified middle cerebral artery second suture method from Zea-Longa. The rats were sacrificed 22 hours after reperfusion in the end of middle cerebral artery occlusion （MCAO）. That was to say, after 10-minute preischemia, suture was exited to the extemal carotid artery and embedded subcutaneously. Middle cerebral artery was occluded again to form the second reperfusion at the set time point after reperfusion. Twenty-two hours later, rats were sacrificed; In the sham-operation group,the preischemia was substituted by sham-operation（only common carotid artery and crotch were exposed, and MCAO by suture was omitted）, and the other procedures were the same as those in the IPC group. In the control group, rats were given sham-operation twice at an interval of one day, and they were sacrificed 24 hours after the second sham-operation. ② Brain tissue was taken from the rats in each group. Cerebral infarction area of each layer was measured with TTC staining, and total cerebral infarction volume （The total cerebral infarction area of each layerxinterspace ） was calculated. After brain tissue was stained by haematoxylin-esoin （HE）, the form of nerve cells was observed under an optical microscope, and the expressions of HIF-1α（and EPO protein in the brain tissue were detected with immunohistochemical method. MAIN OUTCOME MEASURES： ①Cerebral infarction volume;②form of nerve cell; ③ the expression of HIF-1α and EPO protein in the brain tissue. RESULTS：Totally 84 rats were enrolled in the experiment. The dead rats were randomly supplied during the experiment, and finally 84 rats entered the stage of result analysis. ① Detection of cerebral infarction volume of rats in each group： Cerebral infarction volume in the IPC group was significantly smaller than that in the sham-operation group on the 1^st, 3^rd and 7^th days after reperfusion respectively [（161.2±6.9） mm^3 vs （219.9±11.2） mm^3, （134.9±9.0） mm^3 vs （218.6±13.0） mm^3, （142.9±13.7） mm^3 vs （221.3±14.2） mm^3, t=-8.924, 10.587,7.947, P〈 0.01]. ② Observation of nerve cell form of brain tissue： HE staining showed that the ischemic degree, range and cerebral edema degree of IPC group were significantly milder than those of sham-operation group. ③ The expressions of HIF-1α and EPO protein in cerebral cortex and hippocampus ： The expression of HIF-1αof IPC group was significantly higher than that of sham-operation group on the 1^st, 3^rd and 7^th days after reperfusion respectively （125.93±3.79 vs 117.65±5.60, 140.63±4.64 vs 119.33±4.26, 131.15±2.74 vs 107.60±3.89, t=2.449, 6.763,9.899,P 〈 0.05-0.01）. The expression of EPO of IPC group was significantly higher than that of sham-operation group on the 3^rd and 7^th days after perfusion respectively （141.68±3.29 vs 126.33±4.51, 138.88±2.59 vs 125.58±6.18,t=5.499,3.970, P〈 0.05）. CONCLUSION ： ①IPC can protect the never cells in rat brain and the best time to onset of cerebral IT induced by IPC is 1 to 7 days after reperfusion. ② Neuroprotective effect of cerebral IT might be related to the expression of HIF-1α and its target gene EPO.

模拟高原训练对大鼠促红细胞生成素(EPO)表达的影响

为了进一步研究高原训练对大鼠红细胞生成的影响，本研究以大鼠１８Ｓ－ｒＲＮＡ为内参照，用定量反转录聚合酶链式反应（ＱＲＴ－ＰＣＲ），测定了６０只ＳＤ雄性大鼠在模拟不同海拔游泳训练后ＥＰＯ ｍＲＮＡ的变化。结果表明，所有高原对照组中ＥＰＯ ｍＲＮＡ水平均高于平原对照组，其中高原３０００米组和４０００米组较平原对照组有显著性增加Ｐ＜０．０５。在高原训练组中，除了高原２０００米训练后１周组及２周组较高原２０００米对照组ＥＰＯ ｍＲＮＡ水平有较大幅度增加外，其余各高原训练组ＥＰＯ ｍＲＮＡ水平较该组对照均有不同程度的下降。其中高原３０００米训练后１周组及２周组较高原３０００米对照组ＥＰＯ ｍＲＮＡ水平有显著水平的下降Ｐ＜０．０５，而高原４０００米训练后１周组及２周组较高原４０００米对照组ＥＰＯ ｍＲＮＡ水平有非显著水平的下降Ｐ＞０．０５。

间歇低氧训练对大鼠肾脏EPO基因表达的影响

为探讨间歇低氧训练对大鼠肾脏。EPO mRNA基因表达的影响,为高原训练方案的制定提供理论依据,用RT-PCR技术检测大鼠肾脏。EPOmRNA水平。结果表明急性低氧应激后大鼠肾脏EPO mRNA表达水平均显著性升高(P<0.05),急性低氧运动组升高极显著(P<0.01);海拔3000 m间歇低氧训练组EPO mRNA表达水平显著性升高(P<0.05)。认为海拔3000 m的间歇低氧训练能稳定EPO mRNA表达的上调。提示3000 m的海拔高度可能是较适宜间歇低氧训练的海拔高度。

高原训练对促红细胞生成素(EPO)的影响

高原训练作为一种能提高运动员运动成绩的有效手段,广泛被教练员们所采用。其主要的作用机制是通过提高血中促红细胞生成素(erythropoietin,EPO)的含量,使红细胞的生成增加,从而增强机体携带氧的能力,使运动能力得到提高。为此,本文将高原训练对促红细胞生成素的影响加以综述,以便更好的指导运动训练。

高原训练对促红细胞生成素(EPO)的影响

高原训练作为一种能提高运动员运动成绩的有效手段,广泛被教练员们所采用,其主要的作用机制是通过提高血中促红细胞生成素(erythropoietin,EPO)的含量,使红细胞的生成增加,从而增强机体携带氧的能力,使运动能力得到提高.为此,该文将高原训练对促红细胞生成素的影响加以综述,以便更好的指导运动训练.

高原训练对男子赛艇运动员EPO和红细胞系等指标影响的研究

目的:探讨八周高原训练对优秀男子赛艇运动员促红细胞生成素(EPO)和红细胞系等指标的影响。方法:12名男子赛艇运动员在云南会泽(2210米)进行8周高原训练,在高原训练前的第3天、高原训练的第2天、第5天、第10天、第24天、第35天、第56天以及高原训练结束后的第14天、第28天等测试运动员的EPO和红细胞系等指标。结果:与高原训练前相比,高原训练的第2天EPO、RBC和Hgb分别提高了27.21%、6.04%和2.88%;在第56天分别提高了8.37%、10.63%(P<0.05)和4.72%;在高原训练结束后14天分别提高了21.92%、9.11%(P<0.05)和7.74%(P<0.05)。结果提示,8周高原训练能够有效地提高运动员EPO和红细胞(RBC)等水平,但其变化规律不同于常规的4-6周高原训练。而RBC和血红蛋白(Hgb)等呈现波浪形的变化趋势,这可能跟运动训练的量和强度密切相关。而初次与多次高原训练的运动员在相关指标的变化上具有不同的规律,提示初次进行高原训练的运动员对高原环境更加敏感。

优秀赛艇运动员专项有氧能力对高原训练应答的差异

目的:研究我国优秀赛艇运动员专项有氧能力在8周高原训练后的应答差异及其与促红细胞生成素等的关系。方法:以备战2016年里约奥运会的39名优秀赛艇运动员为研究对象,进行8周高原训练。结果:(1)测功仪6 km成绩总体提高0.10%,应答者平均提高0.67%,不应答者总体下降0.91%;(2)高原训练的第3天,促红细胞生成素和血红蛋白浓度总体分别提高38.41%、4.05%;高原训练的第15天与第3天相比,促红细胞生成素和血红蛋白浓度总体分别下降17.25%、0.58%。结论:(1)赛艇运动员的专项有氧能力变化经过高原训练呈现明显的个体差异;(2)高原训练的应答者与不应答者在高原训练过程中的促红细胞生成素和血红蛋白浓度表现不同的变化规律。(3)2组运动员高原训练第3天促红细胞生成素应激程度和第15天的适应程度存在明显不同,但与专项有氧能力的改善并无明显的线性关系。

常压模拟高住低练对大鼠心肌血管内皮生长因子基因表达的影响

目的 :探讨常压下不同低氧 ( 1 4 5 %、1 2 6%氧含量 )模拟高住低练对心肌血管内皮生长因子mRNA表达的影响 ,为运动与低氧适应提供理论依据。方法 :用RT -PCR技术检测大鼠心肌VEGFmRNA水平。结果 :常压下不同低氧模拟高住低练对大鼠心肌VEGFmRNA表达作用结果不同 ,常压下 1 4 5 %氧含量 (相当于海拔 3 0 0 0m)模拟高住低练能稳定VEGF的上调 ,而在常压下1 2 6%氧含量 (相当于海拔 40 0 0m)模拟高住低练时VEGFmRNA基因表达量却减少。结论 :只有选择在适宜的氧含量 (海拔高度 )进行高住和安排好运动训练持续时间 (低练 )

高原和低氧训练对促红细胞生成素影响的研究进展

高原和低氧训练已成为运动员训练的主要方式和手段,其训练目的主要是提高氧运输和摄取能力。目前对促红细胞生成素在训练中变化的报道较多,但在高原训练时间长短以及高原和低氧训练对促红细胞生成素影响异同等方面还没有报道。笔者通过查阅大量文献和对专家进行访谈,对高原训练和低氧训练促红细胞生成素研究进展加以综述,以便对高原和低氧训练过程中促红细胞生成素的影响规律有更加深刻和系统的了解。