低氧增强小鼠脑微血管内皮细胞CD73表达

目的：探讨低氧对小鼠脑微血管内皮细胞系bEnd.3细胞CD73的表达及活性的影响。 方法： ①构建bEnd.3细胞低氧模型。②用乳酸脱氢酶检测试剂盒测定细胞上清液中乳酸脱氢酶的含量。③高压液相层析法检测细胞 CD73的活性。④半定量RT-PCR法检测细胞CD73的mRNA表达。⑤生物素化bEnd.3细胞表面蛋白，继而用免疫沉淀及Western blot方法检测CD73蛋白表达。 结果： ①低氧24 h之后bEnd.3细胞乳酸脱氢酶漏出显著高于正常对照组(P＜0.01)。②低氧能刺激bEnd.3细胞表面CD73的酶活性增高，并呈时间依赖性(P＜0.05)。③低氧4 h、8 h，bEnd.3细胞CD73 mRNA表达增加（P＜0.05）。④低氧12 h、24 h，bEnd.3细胞表面CD73蛋白表达增加（P＜0.05）。 结论： 低氧刺激小鼠脑微血管内皮细胞bEnd.3 CD73 mRNA、蛋白水平及酶活性的提高。     

小鼠成肌细胞低氧/复氧模型的建立及验证

目的:构建体外小鼠成肌细胞间歇性低氧/复氧模型并验证。方法:设定三气培养箱的混合气中1%或4%O₂含量为低氧培养条件,二氧化碳培养箱中的条件为复氧条件,将小鼠成肌细胞(C2C12)分别按不同氧浓度(1%和4%)及复氧循环周期(6 h和8 h)处理,结束后观察细胞增殖情况,测定细胞培养液中葡萄糖、乳酸脱氢酶(lactic dehydrogenase, LDH)及分泌性蛋白质分子——含Ⅲ型纤连蛋白结构域蛋白5(fibronectin type Ⅲ domain containing 5, FNDC5)浓度,测定细胞低氧诱导因子1α(hypoxia-inducible factor-1α, HIF-1α)蛋白的表达水平。结果:(1) 1%低氧浓度组较4%低氧浓度组细胞增殖慢、FNDC5含量低,培养液中葡萄糖浓度高、LDH活性及细胞中HIF-1α蛋白表达较高(P<0.05)。(2)1%低氧浓度条件下,与循环周期6 h组相比,循环周期8 h组细胞活力显著下降(P<0.05)。结论:本研究模拟了体外小鼠成肌细胞在不同低氧/复氧条件下的损伤状况及FNDC5的差异表达...     

慢性低氧时小鼠肺组织低氧诱导因子-1α的表达

目的：研究低氧时小鼠肺组织中低氧诱导因子-1α(HIF-k)表达的变化。方法：实验用雄性小鼠，低氧仓浓度分别为10％、7％、5％。用免疫荧光组织化学技术及共聚焦显微术，检测小鼠在低氧条件下肺组织中HIF-1α表达的变化。结果：正常组小鼠肺组织HIF-1α无表达，低氧组HIF-1α表达增加，且随低氧时间的延长及低氧强度的增加而增强。结论：低氧可诱导小鼠肺组织中HIF-1α的表达增强，(HIF-k)可能参与肺组织细胞凋亡的发生。     

大鼠心脏腺苷预处理心肌组化和细胞化学变化

目的：应用图象分析和电镜细胞化学方法,观察大鼠心脏腺苷预处理心肌琥到脱氢酶、细胞色素氧化酶及Ｃa＾２＋Ｍg＾２＋－ＡＴＰase活性变化。方法：采用ＳＤ雄性大鼠３２只 分４组,即正常对照组（ＮＣ）,缺血/再灌组（Ｉ/Ｒ）,缺血预处理组,腺苷预处理组。用图象分析检测琥珀酸脱氢酶、细胞色素氧化酶和Ｃa＾２＋Ｍa＾２＋－ＡＴＰase活性。 结果：在缺血预处理组及腺苷预处理组琥珀酸脱氢酶、细胞色素氧化酶、Ｃa＾２＋Ｍa＾２     

间歇低氧小鼠胰腺β细胞凋亡及其机制的实验研究

目的: 探讨间歇低氧对小鼠胰腺β细胞凋亡的影响及其可能机制。方法: 将30只雄性C57BL/6J小鼠随机分为间歇低氧组、持续低氧组和正常对照组,每组10只。实验结束后测定各组小鼠的胰岛素耐量;采用化学比色法测定胰腺组织丙二醛(MDA)含量和超氧化物歧化酶(SOD)活性;用real-time PCR检测小鼠胰腺组织中锰超氧化物歧化酶(MnSOD)和谷胱甘肽过氧化酶(GPx1) mRNA的表达水平;并用TUNEL染色检测胰腺β细胞凋亡。结果: 间歇低氧组小鼠胰岛素抵抗水平及胰腺组织中MDA水平显著高于正常对照组和持续低氧组 (P<0.01);胰腺组织SOD活性显著低于正常对照组和持续低氧组(P<0.01);抗氧化酶MnSOD和GPx1 mRNA的表达水平显著低于正常对照组和持续低氧组 (P<0.01);而胰腺β细胞凋亡率显著高于正常对照组和持续低氧组(P<0.01)。持续低氧组与正常对照组上述各种指标的比较均无显著差异(均P＞0.05)。结论: 间歇低氧可导致胰腺组织氧化应激状态和胰腺β细胞凋亡,这可能是阻塞性睡眠呼吸暂停低通气综合征患者胰岛素抵抗及2型糖尿病的病理生理基础之一。     

非酒精性脂肪肝病模型小鼠的肝脏病理变化及肝细胞获取方法

目的 检测非酒精性脂肪肝病（NAFLD）模型小鼠的肝脏病理变化,并探索一种获得大量高活性、高纯度的NAFLD小鼠原代肝细胞的实验方法。方法 60只小鼠随机分为正常组（正常饲料,CD）和高脂组（高脂饲料,HFD）,分饮食饲养20周。定期检测小鼠的体质量,苏木精-伊红（HE）染色和天狼猩红染色观察肝脏组织病理特点。高脂饮食15周时,原位灌注Ⅳ型胶原酶6～8 mL消化得到混合肝细胞,铺于40%的Percoll分离液上,进行密度梯度离心获得纯化的肝细胞,锥虫蓝染色确定细胞的活性,显微镜观察其形态。结果 随着建模时间的延长,HFD组小鼠的体质量逐渐增加,且增幅显著高于CD组;HFD组小鼠肝脏脂肪变性程度增加,在第20周伴随出现了纤维化;建模15周时,每只NAFLD小鼠可获得5×10⁷～7×10⁷个肝细胞,细胞存活率≥85%,细胞纯度≥95%,细胞呈圆形或椭圆形,其边缘平滑,且聚团少;通过精准控制温度、降低胶原酶浓度、使用低速离心和低速密度梯度离心等优化条件后,获得的细胞数量和质量均有显著提高。结论 成功构建了NAFLD小鼠模型,并揭示了不同疾病阶段肝脏...     

低氧条件下低氧诱导因子-1α及p53的表达

目的　研究低氧时小鼠肺组织中低氧诱导因子 1α及凋亡相关基因p5 3蛋白表达的变化 ,探讨两者之间的关系。　方法　实验用雄性昆明小鼠 ,分为低氧组和对照组 ,低氧仓浓度分别为 10 %、7%、5 %。用免疫荧光组织化学技术及激光共聚焦扫描显微镜技术 ,检测小鼠在低氧条件下肺组织中HIF 1α及p5 3蛋白表达的变化。　结果　正常组小鼠肺组织HIF 1α无表达 ,p5 3少量表达 ;低氧组HIF 1α及p5 3蛋白表达均增加 ,并且随低氧时间的延长及低氧强度的增加而增强 ,P <0 0 5 ,HIF 1α及p5 3的表达呈显著正相关 (r=0 97)。　结论　低氧可诱导小鼠肺组织中HIF 1α的表达增强 ,同时肺组织p5 3蛋白的表达上调 ,两者呈显著正相关 ,说明HIF 1α有可能参与肺组织p5 3蛋白表达的调节 ,进而调节凋亡的发生。     

反复低氧对小鼠脑内神经肽Y免疫反应活性的影响

目的:观察反复低氧对小鼠脑内神经肽Y(NPY)免疫反应活性的影响。方法:昆明小鼠40只随机分为对照组、低氧1次(H₁)组、低氧2次(H₂)组、低氧3次(H₃)组和低氧4次(H₄)组。对低氧各组动物分别行不同次数的反复低氧。各组动物脑内NPY的免疫反应活性采用放射免疫测定法测定。结果:小鼠对低氧的标准耐受时间随反复低氧次数的增加而显著增加。经1次低氧和2次低氧后小鼠脑内NPY的免疫反应活性明显提高,分别为正常对照组的145.5%±3.2%和147.3%±2.5%(P＜0.01);而低氧3次后则降到正常对照水平。结论:反复低氧通过预适应能显著提高小鼠对低氧的耐受性,并可诱导小鼠脑内NPY免疫反应活性在预适应形成的早期一过性地上升。     

穿孔素介导的细胞凋亡机制在抗流感病毒感染免疫防御中作用的研究

目的：穿孔素介导的细胞凋亡机制在流感病毒初次感染中作用的研究。方法：用流感病毒A／PR／8／34经鼻感染穿孔素基因敲除鼠和同源对照C57BL／6小鼠，采用PFU方法测定肺内流感病毒增殖状况；免疫组织化学染色方法观察小鼠病毒感染后感染细胞的凋亡情况；利用乳酸脱氢酶释放法检测感染鼠脾淋巴细胞NK活性及CTL杀伤活性。结果：穿孔素基因缺乏导致流感病毒在小鼠肺内大量增殖；小鼠清除感染病毒所需时间延长；病毒感染细胞发生凋亡的时间亦因穿孔素的缺乏而延迟；感染小鼠脾淋巴细胞NK活性及CTL杀伤活性均显著降低。结论：穿孔素依赖的细胞介导的细胞毒效应在控制流感病毒初次感染，快速清除感染病毒方面起重要作用。     

CCl4肝纤维化过程中肝组织金属硫蛋白与肝星状细胞MMP-2表达及活性之间相关性研究

目的： 研究金属硫蛋白（MT）在体内及体外与基质金属蛋白酶-2(MMP-2)表达、活性之间的相关性。方法: 昆明种雄性成年小鼠50只,其中实验鼠 40只,对照鼠10只,用CCl4诱导小鼠肝纤维化模型。向肝星状细胞（HSCs）条件培养基（含有MMP-2）中加不同浓度MT,使之与MMP-2酶学共浴,检测MMP-2活性。制作小鼠肝组织芯片,天狼猩红染色判断肝纤维化程度。免疫组化法测肝组织MMP-2、MT蛋白表达,酶图法测鼠肝组织匀浆和培养基中MMP-2活性。结果: ①模型组小鼠肝组织MMP-2和MT蛋白表达水平均随纤维化进展而呈波浪式交替升高,但二者时相变化相反。 ②模型组小鼠肝组织MMP-2活性随实验时间的增加而逐渐升高,亦有波动。除个别时点外,酶活性与MT表达呈负相关。③肝星状细胞条件培养基与不同浓度的MT直接作用后,MMP-2活性随MT浓度增加活性逐渐降低(P＜0.01)。结论: 在小鼠肝纤维化发生发展过程中,肝组织MT蛋白和MMP-2蛋白表达均有上升趋势,二者间可能存在相互作用;MT蛋白和MMP-2活性呈负相关,前者对后者可能起抑制作用。     

Microphotometric study on cytochrome oxidase and lactate dehydrogenase activities in mouse spermatozoa during maturation and in vivo and in vitro capacitation

In Eutherian (mammalian) spermatozoa, maturation and capacitation are associated to modifications of the metabolic activities. In order to demonstrate such variations, a quantitative cytochemical study was carried out on cytochrome oxidase and L-lactate dehydrogenase activities in mouse spermatozoa collected from the male and female genital tracts and at different times of the in vitro capacitation. Microdensitometric measurements were made on a Vickers M85 integrator microdensitometer at lambda = 480 +/- 5 nm and lambda = 585 +/- 5 nm wavelengths for the cytochrome oxidase and LDH activities, respectively. The cytochrome oxidase activity first decreases and then increases significantly both during maturation and during capacitation in vivo and in vitro. The LDH activity decreases significantly and gradually in the male and female genital tracts as well as in the course of in vitro capacitation where, however, an enhancement in the anaerobic glycolysis occurs.     

七氟烷预处理抑制缺氧诱导的脑损伤

目的:观察七氟烷预处理对缺氧小鼠脑损伤的影响及其可能机制。方法:将60只雄性C57BL/6J小鼠,随机分为对照(C)组、缺氧(H)组、2%七氟烷预处理30 min组(S1+H组)、2%七氟烷预处理60 min组(S2+H组)和4%七氟烷预处理30 min组(S3+H组),每组10只。缺氧即持续吸入O2体积分数为(6.5±0.1)%的氮氧混合气体24 h构建缺氧模型;预处理即以O2体积分数为(21.0±0.5)%的氮氧混合气体为载气,分别吸入2%七氟烷30 min、2%七氟烷60 min和4%七氟烷30 min,洗脱15 min后进行缺氧处理。用光学显微镜及透射电子显微镜(TEM)观察海马CA1区形态学改变;比色法检测血清乳酸脱氢酶(LDH)活性;ELISA测定脑组织促红细胞生成素(EPO)和血管内皮生长因子(VEGF)含量;同时测定脑组织丙二醛(MDA)含量及超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GPx)活性。结果:缺氧24 h后,光镜下可见海马CA1区细胞水肿或固缩;各预处理组病理改变轻于H组。TEM下S2+H组细胞超微结构最为完整。H组血清LDH活性及脑组织EPO、VEGF、MDA含量显著高于C组,脑组织的SOD及GPx活性较C组明显降低。七氟烷预处理后血清LDH活性及脑组织EPO、VEGF含量较H组降低,以S2+H组最为显著;脑组织MDA含量及SOD活性降低,而GPx活性有所升高。结论:七氟烷预处理能减轻缺氧引起的脑组织损伤,其机制可能与调节抗缺氧蛋白合成及降低氧化应激有关。     

DNA甲基转移酶1、3A和3B在低氧预适应小鼠大脑中的表达简

 目的 研究DNA甲基转移酶（DNMT）1、3A和3B在低氧预适应小鼠大脑中的变化,探讨低氧预适应形成过程中DNMTs的变化与脑保护作用的关系。方法 小鼠随机分成常氧组（H0）、低氧1次组（H1）或4次（H4）后取大脑皮质组织,应用实时定量PCR 技术、免疫印迹技术和DNA甲基转移酶活性检测DNMT1、DNMT3A和DNMT3B mRNA和蛋白质及DNMT活性。结果H1组和H4组DNMT3A和DNMT3B的mRNA和蛋白质水平较H0组显著降低（p<0.05）,H4组DNMT活性较H0组降低（p<0.05）。结论DNMT3A和3B水平及DNMT活力的变化可能与低氧预适应小鼠获得脑保护的关系密切。     

ATP and cytochrome c-dependent activation of caspase-9 during hypoxia in the cerebral cortex of newborn piglets

In previous studies, we have shown that cerebral hypoxia results in increased activity of caspase-9, the initiator caspase, and caspase-3, in the cytosolic fraction of the cerebral cortex of newborn piglets. The present study examines the mechanism of caspase-9 activation during hypoxia and tests the hypothesis that the ATP and cytochrome c-dependent activation of caspase-9 increases in the cytosol of the cerebral cortex of newborn piglets. Newborn piglets were divided into normoxic (Nx, n=4), and hypoxic (Hx, n=4) groups. Anesthetized, ventilated animals were exposed to an FiO(2) of 0.21 (Nx) or 0.07 (Hx) for 60 min. Cerebral tissue hypoxia was documented biochemically by determining levels of ATP and phosphocreatine (PCr). Cytosolic fraction was isolated and passed through a G25-Sephadex column to remove endogenous ATP and cytochrome c. Fractions were collected and protein determined by UV spectrophotometry at 280 nm. Eluted high-molecular weight samples from normoxic and hypoxic animals were divided into four subgroups: subgroup 1 (control), incubated without added ATP and cytochrome c; subgroup 2, incubated with added ATP; subgroup 3, incubated with added cytochrome c; and subgroup 4, incubated with added ATP and cytochrome c. The incubation was carried out at 37 degrees C for 30 min. Following incubation, the protein was separated by 12% SDS-PAGE and active caspase-9 was detected using specific active caspase-9 antibody. Protein bands were detected by enhanced chemiluminescence. Protein density was determined by imaging densitometry and expressed as absorbance (OD x mm(2)). ATP (mumol/g brain) level was 4.7 +/- 0.18 in normoxic, as compared to 1.53 +/- 0.16 in hypoxic (p < 0.05 vs. Nx). PCr (mumol/g brain) level was 4.03 +/- 0.11 in the normoxic and 1.1 +/- 0.3 in the hypoxic brain (p < 0.05 vs. Nx). In the normoxic preparations, active caspase-9 density increased by 9, 4 and 20% in the presence of ATP, cytochrome c and ATP+cytochrome c, respectively. In the hypoxic preparations, active caspase-9 density increased by 30, 45 and 60% in the presence of ATP, cytochrome c and ATP+cytochrome c, respectively. These results show that incubation with ATP, cytochrome c and ATP+cytochrome c result in a significantly increased activation of caspase-9 in the hypoxic group (p < 0.05). We conclude that the ATP and cytochrome c dependent activation of caspase-9 is increased during hypoxia. We propose that the ATP and cytochrome c sites of apoptotic protease activating factor I that mediate caspase-9 activation are modified during hypoxia.     

Urocortin-I预处理对离体大鼠心肌线粒体呼吸功能及呼吸酶活性的影响

目的:探讨urocortin-I预处理对离体大鼠缺血再灌注心肌线粒体呼吸功能及酶活性的影响,观察心肌细胞ATP含量的变化。方法:(1)健康雄性SD大鼠随机分为4组:正常组(Nor组)、缺血再灌注组(IR组)、urocortin-I预处理组(Ucn I组)、5-羟葵酸(5-HD)拮抗urocortin-I组(5-HD+Ucn I组)。采用Langendorff装置建立大鼠离体心脏缺血再灌注模型。分别于平衡末(T_1)、缺血前(T_2)及再灌注末(T_3)分离、提取心肌线粒体,测定各组线粒体呼吸功能及呼吸酶活性。(2)利用MPA离体心脏灌注装置分离成年大鼠心肌细胞,将分离培养24 h后同批次的心肌细胞随机分为正常组(Nor组)、缺氧复氧组(I/R组)、urocortin-I预处理组(Ucn I组)、5-HD拮抗urocortin-I组(5-HD+Ucn I组)。建立缺氧复氧模型,于复氧末用高效液相色谱法检测各组心肌细胞ATP含量。结果:T_3时点除Nor组外,其余各组与T_1、T_2时点相比呼吸功能(3态呼吸速率、呼吸控制率)及琥珀酸氧化酶、NADH氧化酶、细胞色素C氧化酶活性均明显下降(P0.05);T_3时Ucn I组心肌线粒体的呼吸功能及呼吸酶活性明显优于5-HD+Ucn I组及IR组(P0.05),但次于Nor组(P0.05);T_3时5-HD+Ucn I组心肌线粒体的呼吸功能及呼吸酶活性(琥珀酸氧化酶、NADH氧化酶)较IR组好(P0.05),但2组间细胞色素C氧化酶活性差异无统计学显著性;T_1、T_2时点各组组内及组间呼吸功能及3种呼吸酶活性的差异无统计学显著性。心肌细胞实验结果显示,复氧末Nor组ATP含量较其余各组均高(P0.01);I/R组和5-HD+Ucn I组心肌细胞的ATP含量较Ucn I组低(P0.05);此外,5-HD+Ucn I组心肌细胞的ATP含量较I/R组高(P0.05)。结论:Ucn I预处理可减轻缺血再灌注对心肌线粒体呼吸功能及呼吸酶活性的干预,保证了缺氧/复氧后心肌ATP的含量。     

化学预处理对低氧预适应模型小鼠的影响

背景：低氧诱导因子1α调节一些增加抗低氧耐受的基因的表达。氯化钴是一种能够稳定低氧诱导因子1α的化学试剂。 目的：检测氯化钴预处理对急性重复低氧小鼠的影响。 方法：Balb/C小鼠随机分为预处理组和对照组,实验前3 h,两组分别注射氯化钴和生理盐水后, 分别进行0次(正常对照组),1次,4次缺氧暴露,随即分别取海马组织进行指标检测。 结果与结论：预处理组缺氧暴露1次对低氧耐受时间显著高于对照组缺氧暴露1次,预处理组缺氧暴露1次,4次低氧耐受时间差异无显著性意义。对照组中缺氧暴露4次组低氧诱导因子1的DNA结合活力显著高于缺氧暴露1次组和正常对照组,组间比较差异有显著性意义。预处理组中缺氧暴露1次组低氧诱导因子1的DNA结合活力显著高于正常对照组(P < .01),缺氧暴露4次组低氧诱导因子1的DNA结合活力急剧下降,显著低于缺氧暴露1次组和正常对照组。对照组促红细胞生成素和血管内皮生长因子mRNA 在缺氧暴露1次组和缺氧暴露4次组升高,各组间比较差异有显著性意义(P < 0.05)。预处理组促红细胞生成素和血管内皮生长因子mRNA表达组间比较差异无显著性意义。提示氯化钴预处理能够提高低氧耐受时间,降低低氧预适应诱导的耐受时间及低氧诱导因子1 DNA结合能力。     

Temporal changes of plasma erythropoietin level in hypobaric hypoxic mice and the influence of an altered blood oxygen affinity

Temporal changes of plasma erythropoietin (Epo) in mice exposed to hypobaric hypoxia were studied by a fetal mouse liver cell culture method. Since a colony formation inhibitory activity was found in the mouse plasma, thirteen pretreatment procedures for bioassay were compared and the procedure of shaking with chloroform followed by dialysis was concluded to be the best. When normal mice (P50 = 40.4 +/- 2.2 Torr) were exposed to hypoxia of 350 Torr, the plasma Epo level was elevated, with peak at the 2nd to 3rd day, and afterwards declined gradually. On the contrary, cyanated mice (P50 = 30.1 +/- 1.5 Torr) showed much less of the Epo response when exposed to 350 Torr. Under 200 Torr hypoxia, both mice exhibited a similar and remarkable extent of the response. These results suggest that the renal Epo-producing tissue or its oxygen-sensing system is less hypoxic in cyanated mice than in normal mice under 350 Torr, and that the physiologically optimal oxygen affinity of blood is variable depending on hypoxic degrees. The fact that the inhibitory activity showed an inverse temporal change to that of Epo, suggested a possible important role of this activity in the regulation of erythropoiesis under hypoxia.     

Rat liver mitochondrial enzyme activities in hypoxia.

Rat liver mitochondrial enzyme activities were measured after exposing the animals to the atmospheric pressure of 380 mm Hg for 5 h and 14 days. Succinate dehydrogenase and succinate oxidase activities increased significantly during the hypoxic period of 14 days. No change was observed in cytochrome oxidase activity. Malate dehydrogenase and glutamate dehydrogenase activities increased somewhat, but not significantly. The efficiency of oxidative phosphorylation (the ADP:O ratio) in the isolated mitochondria remained unchanged. The exact mitochondrial protein values showed a 15% decrease as compared with the control group. The concentrations of cytochromes did not change significantly in the hypoxic group. During the short hypoxic period succinate dehydrogenase, succinate oxidase and cytochrome oxidase activities increased as compared with those in the control group.     

L-精氨酸和牛磺酸联合抗缺氧损伤及防治缺氧性肺动脉高压的研究

目的研究L-精氨酸、牛磺酸联合应用的抗缺氧损伤以及对缺氧性肺动脉高压(HPH)的防治效果。方法雄性W istar大鼠40只,制作缺氧性HPH模型,随机分为平原对照组(C)、单纯缺氧组(H)、缺氧 L-精氨酸组(Arg)、缺氧 牛磺酸组(Tau)、缺氧 牛磺酸 L-精氨酸组(TA),测定各组的肺动脉压(mPAP)、右心室肥大指数(RVH I)、血浆乳酸脱氢酶(LDH)、脂质过氧化产物丙二醛(MDA)、肺匀浆NO含量的变化。结果H组与C组相比,mPAP高出约25 mmHg(P<0.01),RVH I增加1.56倍(P<0.01),血浆LDH活性增高10.1倍(P<0.01),血浆MDA含量增加1.64(P<0.01),而肺匀浆NO含量降低68%(P<0.01)。各治疗组与H组相比,mPAP均显著降低5 mmHg(P<0.05),RVH I均显著降低20%(P<0.01),血浆LDH活性显著降低(P<0.01),其中TA组与Arg组比较有显著差异(P<0.01),血浆MDA含量显著降低(P<0.01),但各治疗组之间无显著性差异。肺匀浆NO含量在Tau组无显著性变化,在Arg和TA组显著回升(P<0.01)。结论L-精氨酸和牛磺酸具有抗缺氧损伤及防治肺动脉高压的效果,两者联用可进一步增加NO产生,减少乳酸脱氢酶的漏出,加强细胞保护作用。     

Hypoxia-induced renal epithelial cell death through caspase-dependent pathway: role of Bcl-2, Bcl-xL and Bax in tubular injury

Although injury of epithelial cells has been reported to be responsible for renal disease such as acute renal failure, its molecular mechanisms are largely unknown. As hypoxia has been postulated as the initial trigger of epithelial injury, we studied the molecular mechanisms of apoptosis induced by hypoxia in human renal epithelial cells. Severe hypoxia caused epithelial cell death, accompanied by a significant increase in LDH release (p<0.01). In addition, hypoxic treatment of epithelial cells resulted in a significant increase in apoptotic cells as assessed by cell morphology (p<0.01). The apoptotic change in epithelial cells under hypoxic condition was also confirmed by a significant increase in caspase-3-like activity and release of cytochrome c (p<0.01). The decrease in epithelial cell number was completely abolished by addition of a wide-spectrum caspase inhibitor, Z-VAD, rather than Z-DEVD, a specific caspase-3 inhibitor (p<0.01). Thus, we further studied the molecular mechanisms of apoptosis induced by hypoxia. Anti-apoptotic factors, Bcl-2 and Bcl-xL, were significantly decreased in epithelial cells under a hypoxic condition as assessed by Western blotting (p<0.01). In contrast, hypoxia did not alter their location. Of particular importance, translocation of a proapoptotic factor, Bax, from the cytoplasm to the mitochondrial membrane was observed in response to hypoxia, whereas total Bax protein was not changed by hypoxia. Overall, this study demonstrated that hypoxia caused epithelial cell death induced by caspase-3-like activity-dependent apoptosis. The pro-apoptotic mechanisms of hypoxia in epithelial cells largely depend on a significant decrease in Bcl-2 and Bcl-xL. In addition, the present results demonstrate that translocation of Bax from the cytosol to the mitochondrial membrane occurred under hypoxia, thereby leading to pathological tissue destruction.