骨桥蛋白对RANKL诱导破骨细胞分化的影响

 目的 初步探讨骨桥蛋白对破骨细胞体外分化的影响。方法 体外培养小鼠破骨前体RAW264.7细胞,RANKL诱导刺激其分化为破骨细胞,并加入骨桥蛋白进行干预。MTT法及TRAP染色分别检测破骨细胞细胞增殖及前体破骨细胞分化情况,RT-PCR检测RANK的mRNA表达水平。结果 骨桥蛋白可明显促进RAW264.7细胞向破骨细胞分化、增加细胞增殖,与对照组相比差异具有统计学意义(P＜0.05),并使破骨细胞特征性基因RANK的mRNA表达上调约2.67倍。结论 骨桥蛋白可能通过影响RANK/RANKL信号通路促进RAW264.7细胞分化为破骨细胞,有望成为防治骨质疏松等骨相关疾病的新靶点。
     

降钙素基因相关肽对成骨细胞核因子-κB受体活化因子配体及其饵受体表达的影响

目的:探讨外源性降钙素基因相关肽(CGRP)对体外培养兔成骨细胞核因子-κB受体活化因子配体(RANKL)及其饵受体骨保护素(OPG)表达的影响。方法:将体外培养的兔成骨细胞用不同浓度的CGRP作用24h后,通过免疫细胞化学及图像分析的方法观察成骨细胞OPG、RANKL表达强度的变化。结果:CGRP呈剂量依赖性的上调成骨细胞OPG的表达同时下调RANKL的表达。结论:CGRP上调成骨细胞OPG/RANKL/的表达比值,从而间接调节破骨细胞分化及活性。     

低氧对小鼠成骨细胞OPG及RANKL基因表达的影响

目的:观察低氧对体外培养的小鼠成骨细胞护骨素(osteoprotegerin,OPG)及NF-κB受体活化因子配体(receptor activator of NF-κB ligand,RANKL)基因表达的影响。方法:取出生24h内的新生小鼠40只,在无菌条件下取其颅盖骨,去除纤维组织,用胰蛋白酶-胶原酶消化法进行成骨细胞的原代培养。取第3~5代细胞分为常氧组和低氧组(3%O2),分别缺氧6、12、24、48和72h后,从培养液贴壁细胞中抽提总RNA,应用RT-PCR检测各组OPG和RANKL的基因表达变化。结果:低氧组各时间点OPG基因表达均较常氧组显著减弱,且随时间延长而减弱;而RANKL基因表达均较常氧组显著增强,以24h时最为明显。结论:低氧可以抑制小鼠成骨细胞OPG基因表达,同时刺激RANKL基因的表达。     

电离辐射对成骨细胞核因子κB受体活化因子配体和骨保护素mRNA及其蛋白表达的影响

目的 研究电离辐射对成骨细胞RANKL和OPG表达的影响,探讨辐射导致骨损伤的分子机制。方法 采用MC3T3-E1细胞诱导分化为成骨细胞,经0、2和4 Gy¹³⁷Cs γ射线照射后,采用实时定量PCR及Western blot方法检测电离辐射对于成骨细胞RANKL和OPG mRNA及其蛋白水平表达的影响。结果 4 Gy照射可以导致成骨细胞RANKL mRNA(t=5.41,P<0.05)及其蛋白(t=68.37,P<0.01)表达水平上调;2和4 Gy照射可以导致成骨细胞OPG mRNA(t=5.20、7.02,P<0.05)及其蛋白(t=7.78、9.45,P<0.05)表达水平下调。结论 2和4 Gy电离辐射可以导致成骨细胞中RANKL/RANK/OPG通路发生改变,促进破骨细胞的分化和成熟,进而促进破骨细胞的骨吸收作用。     

辐射对体外培养的小鼠成骨细胞核因子κB 受体活化因子配体/骨保护素mRNA表达的影响

目的 通过对成骨细胞的RANKL和OPG的基因表达分析揭示辐射对成骨细胞功能的影响.方法 在体外诱导骨髓基质细胞生成成骨细胞,碱性磷酸酶(ALP)染色对其特性进行确定,用RT-PCR方法分析了0～4 Gy照射的早期成骨细胞和成熟成骨细胞的RANKL和OPG的表达.结果 骨髓基质细胞在体外被诱导成的成骨细胞,在0～4 Gy剂量照射下,早期成骨细胞中RANKL的mRNA表达在1 Gy照射时,与0 Gy时相比表达最高,达到2.83倍,但各剂量组明显高于成熟成骨细胞的表达(t=8.34～103.57,P＜0.05).早期成骨细胞各剂量组的RANKL/OPG比值,在1 Gy照射最高达0.225±0.018,但明显高于晚期成骨细胞(t=2.84～20.99,P＜0.05).结论 辐射能够增强早期成骨细胞对破骨细胞功能的调节作用,加重骨组织的损伤.

Abstract：

Objective To study the influence of irradiation on the osteoblast function by the gene expression changes of RANKL and OPG.Methods Bone marrow stromal cells were induced to develop into early and mature osteoblasts in vitro.The characterization of osteoblasts was indentified by ALP staining.The RANKL and OPG mRNA levels in early and mature osteoblasts, which exposed to 0 -4 Gy radiation were determined by RT-PCR.Results Bone marrow stromal cells had been induced to early and mature osteoblasts by osteoblast differentiation medium in vitro.In early stage of osteoblast, RANKL mRNA expression levels treated with 1Gy irradiation was 2.83-fold higher than those other irradiation dosage groups.The RANKL mRNA expression levels of each group in early stage of osteoblasts were significantly higher than those in the mature counterpart ( t = 8.34 - 103.57, P ＜ 0.05 ).The ratio of RANKL/OPG mRNA was obviously greater in early osteoblast compared with the mature cells ( t = 2.84 - 20.99, P ＜0.05 ), and it was the highest in 1Gy irradiation treated early osteoblast.Conclusions Radiation exposure of the early osteoblasts promotes osteoclasts function and results in the bone loss.     

137 Cs γ射线对成骨细胞增殖、分化和矿化的影响

目的 探讨137Cs γ射线对成骨细胞形态、增殖、分化、矿化及细胞因子的影响及分子机制.方法 将成骨细胞分为对照组(0 Gy)及0.5、1.0、2.0和5.0 Gy组,分别接受137Cs γ射线照射,倒置相差显微镜观察各组细胞形态,MTT法测定细胞增殖,PNPP法检测碱性磷酸酶(ALP)活性,茜素红染色法观察矿化功能,RT-PCR半定量检测ALP、骨钙素(OC)、Ⅰ型胶原(collagen Ⅰ)、护骨素(OPG)和NF-kB受体活化因子配体(RANKL)等基因mRNA表达量.结果 1.0 Gy以上照射组抑制成骨细胞增殖(t=6.197～18.677,P＜0.05);2.0 Gy以上照射组致细胞数量减少,折光性减低,细胞间突起连接减少,并可抑制细胞ALP活性和矿化能力(t=2.790 ～ 21.374,P＜0.05).ALP和OC基因mRNA表达量在0.5 Gy以上剂量照射即明显下调(t=3.563～16.508,P＜0.05),OPG、OPG/RANKL在5.0 Gy剂量时表达明显下调(t=12.942、4.954,P＜0.05),Ⅰ型胶原和RANKL基因mRNA的表达未见明显改变.结论 137CsΥ射线照射致成骨细胞形态改变,增殖、分化和矿化能力下降,ALP、OC、OPG等相关基因表达下调,OPG/RANKL通路可能是大剂量电离辐射时骨损伤的主要作用途径之一.     

OPG/RANKL/RANK信号通路在牙槽骨代谢中研究进展

<正>近年来,许多细胞因子被发现在调节骨代谢方面起着重要作用。其中,以骨保护素(osteoprotegerin, OPG)、核因子-κb受体活化因子配体(receptor activator of NF-κb ligand, RANKL)、核因子-κb受体活化因子(receptor activator of NF-κb, RANK)3部分组成的OPG/RANKL/RANK信号通路是众多因子活化破骨细胞的最终环节,在牙槽骨代谢中发挥着重要作用。     

TNF-α对体外培养人牙囊细胞表达RANKL、OPG的影响

目的研究不同浓度的肿瘤坏死因子-α(TNF-α)对体外培养人牙囊细胞中核因子-κB受体活化子配体(RANKL)、骨保护素(OPG)mRNA表达的影响,探讨牙齿萌出过程中TNF-α对破骨细胞形成的作用。方法原代培养人牙囊细胞,取生长状态良好的第5代人牙囊细胞分别与浓度为0(对照)、5、10、25、50、100ng/ml的TNF-α共同孵育6h,提取细胞RNA,RT-PCR检测RANKL、OPG的mRNA表达。以β-actin作内参物,比较各组PCR产物的光密度比值。结果与对照组(TNF-α 0ng/ml)比较,5ng/ml TNF-α可降低人牙囊细胞中OPG的表达(P<0.05),其他不同浓度TNF-α作用后OPG的表达与对照组比较无显著性差异。TNF-α浓度为25、50、100ng/ml时RANKL的表达增强,与对照组比较有显著性差异(P<0.05)。结论TNF-α可增强人牙囊细胞RANKL的表达,降低OPG的表达,提高RANKL/OPG的比值,提示TNF-α在牙齿萌出过程中对破骨细胞的形成有重要作用。     

γ射线对人外周血单核细胞向破骨样细胞诱导分化的影响

目的 探讨电离辐射对人外周血单核细胞来源的破骨细胞体外诱导分化的影响。方法 将人外周血采用密度梯度离心法获得单核细胞,经核因子κB受体活化因子配体(RANKL)和巨噬细胞集落刺激因子(M-CSF)诱导培养24 h,分别给予0、0.75和2 Gy的¹³⁷Cs γ射线照射,第7天行TRAP染色后计数TRAP阳性多核破骨细胞,第10天取象牙骨片基质行甲苯胺蓝染色观察骨吸收陷窝形成;qRT-PCR检测破骨细胞特征标志物组织蛋白酶K和integrin β3的mRNA表达水平;ELISA法检测培养上清液中TRAcP-5b含量。结果 0.75 Gy照射组TRAP染色阳性多核破骨细胞计数显著多于对照组(0 Gy)(t=3.451,P<0.05),组织蛋白酶K和integrin β3的mRNA表达水平明显上调(t=2.343、2.728,P<0.05),且培养液中TRAcP-5b浓度明显增加(t=3.631,P<0.05)。而2 Gy照射组的TRAP染色阳性多核破骨细胞计数少于对照组,并伴有组织蛋白酶K和integrin β3的mRNA表达水平下调、培养上清液中TRAcP-5b浓度下降,但差异无统计学意义。结论 电离辐射可改变人外周血单核细胞破骨样细胞分化趋势,小剂量照射时可促进破骨细胞分化和骨吸收活性,而较大剂量照射后破骨细胞分化和骨吸收活性均降低。     

NICD表达下调对辐射损伤小鼠成骨细胞系MC3T3-E1增殖和功能基因表达的影响

目的利用RNA干扰抑制小鼠成骨细胞系MC3T3-E1表达Notch信号通路胞内结构域（NICD）,探讨靶向抑制NICD表达对辐射损伤MC3T3-E1细胞的增殖和相关功能基因表达的影响。方法建立抑制NICD表达的MC3T3-E1细胞株,利用实时定量PCR（qRT-PCR）和Western blot法检测其NICD基因的表达。MC3T3-E1细胞和NICD RNA干扰MC3T3-E1细胞经2 Gy γ射线照射后,用BrdU掺入法和qRT-PCR法检测上述细胞的增殖及相关功能基因的表达水平。使用Student-Newman-Keuls进行组间差异分析,两组间比较采用t检验。结果用RNA干扰技术可靶向抑制MC3T3-E1细胞表达NICD。抑制NICD表达可干扰前体成骨细胞和成骨细胞的增殖。2 Gy照射后,前体成骨细胞和成骨细胞以及NICD RNA干扰的成骨细胞的增殖明显下降,各靶细胞的相关功能基因与照射前相比的变化如下:①2 Gy照射后的前体成骨细胞成骨特导性转录因子（Runx2）表达上调,差异有统计学意义（t=2.353,P < 0.05）,NICD RNA干扰的前体成骨细胞Runx2表达下调,差异有统计学意义（t=2.353,P < 0.05）;②2 Gy照射后的前体成骨细胞和成骨细胞以及NICD RNA干扰的前体成骨细胞碱性磷酸酶（ALP）表达上调,差异有统计学意义（t=3.182、3.345、3.555,均P < 0.05）,NICD RNA干扰的成骨细胞ALP表达下调,差异有统计学意义（t=5.045,P < 0.01）;③2 Gy照射后前体成骨细胞核因子κB受体活化因子配体（RANKL）表达下调,差异有统计学意义（t=2.541,P < 0.05）,成骨细胞和NICD干扰的前体成骨细胞RANKL表达上调,差异有统计学意义（t=3.299,P < 0.05;t=10.212,P < 0.01）,而抑制NICD表达则发生相反变化,差异无统计学意义（t=0.765,P>0.05）;④2 Gy照射后的前体成骨细胞和成骨细胞骨保护素（OPG）表达下调,差异有统计学意义（t=2.994、2.782,均P < 0.05）,抑制NICD表达使前体成骨细胞OPG表达上调,差异有统计学意义（t=5.841,P < 0.01）,成骨细胞OPG表达下调,差异有统计学意义（t=2.544,P < 0.05）;⑤2 Gy照射后各靶细胞巨噬细胞集落刺激因子（M-CSF）表达变化趋势与RANKL表达变化情况一致。结论在不同阶段的成骨细胞中抑制NICD表达对辐射损伤表现出的作用是不同的:①可降低前体成骨细胞和成骨细胞的增殖,对辐射损伤后的前体成骨细胞的增殖有保护作用;②可通过调节Runx2从而明显抑制辐照后前体成骨细胞分化,减少骨质丢失;③辐照后各成骨细胞不会通过RANKL/OPG/RANK系统表现出对破骨细胞功能的调节作用;④成骨细胞经过调节M-CSF表现出对破骨细胞的功能抑制作用。     

钛-6铝-4钒颗粒对破骨细胞形态和功能的影响

目的在体外条件下观察钛-6铝-4钒（Ti-6AL-4V）颗粒对破骨细胞形态和功能的影响。方法取新西兰大耳兔破骨细胞培养在玻璃盖玻片和牛皮质骨片上，实验组用0．1mg／ml颗粒刺激，经不同时段培养后行抗酒石酸酸性磷酸酶（TRAP）染色，观察颗粒对破骨细胞形态的影响。对骨片上形成的骨吸收陷窝进行甲苯胺蓝染色观察，并用计算机图像分析软件评估吸收面积的大小。结果破骨细胞可以吞噬颗粒，形态变得不规则，特征性TRAP染色加深，较早出现凋亡征象。经颗粒刺激后在骨片上形成的骨吸收陷窝面积较大、数量较多。结论破骨细胞有吞噬功能，吞噬Ti-6AL-4V颗粒后发生形态和功能的变化，骨吸收功能增强。     

Noninvasive imaging of osteoclasts in parathyroid hormone-induced osteolysis using a 64Cu-labeled RGD peptide.

Bone diseases are often a result of increased numbers of osteoclasts, or bone-resorbing cells. Bone metastases are a significant cause of morbidity in many types of cancer. An imaging agent targeting osteoclasts, which are upregulated in osteolytic lesions, may facilitate earlier follow-up in patients with osteolytic or mixed bone metastases. Osteoclasts express high levels of alpha(v)beta3 integrin, to which peptides containing the Arg-Gly-Asp (RGD) sequence are known to bind. We proposed that radiolabeled RGD peptides could be used to detect osteoclasts in lytic bone lesions. METHODS: The cross-bridged macrocyclic chelator 4,11-bis(carboxymethyl)-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane (CB-TE2A) was conjugated to c(RGDyK) for radiolabeling with 64Cu (t(1/2), 12.7 h; beta+, 17.4%; E(beta+ max), 656 keV; beta-, 39%; E(beta- max), 573 keV). The in vitro affinity of Cu(II)-CB-TE2A-c(RGDyK) for alpha(v)beta3 and alpha(v)beta5 was evaluated in a heterologous competitive binding assay. Ex vivo uptake was examined in osteoclasts prepared from bone marrow macrophages. As a proof of principle, biodistribution and imaging studies were performed on parathyroid hormone (PTH)-induced osteolysis in the calvarium. RESULTS: Cu-CB-TE2A-c(RGDyK) was shown to have a 30-fold higher affinity for alpha(v)beta3 than for alpha(v)beta5. Osteoclasts were shown to specifically take up (64)Cu-CB-TE2A-c(RGDyK). However, bone marrow macrophages showed only nonspecific uptake. PTH treatment increased calvarial uptake of 64Cu-CB-TE2A-c(RGDyK), compared with uptake in mice receiving a sham treatment. In addition, calvarial uptake correlated linearly with the number of osteoclasts on the bone surface. CONCLUSION: These results suggest that 64Cu-CB-TE2A-c(RGDyK) selectively binds alpha(v)beta3 on osteoclasts and may potentially be used to identify increased numbers of osteoclasts in osteolytic bone diseases such as osteolytic bone metastasis and inflammatory osteolysis.     

The influence of acute hypoxia on the prediction of maximal oxygen uptake using multi-stage shuttle run test

BACKGROUND: The purpose of this study was to investigate changes in predicted maximal oxygen uptake (VO(2max)) by the multistage shuttle run test (MSSR) and several physiological parameters in MSSR under normoxia and two hypoxic conditions and the influences of acute hypoxia on these changes in MSSR. METHODS: Experimental design: six college long distance runners (LR), seven college rugby athletes (RG) and eight untrained college males (UM) performed incremental running test on the treadmill and MSSR in 17.5% (HYP(17.5%)) and 15.5% (HYP(15.5%)) of oxygen concentration and normoxia (NOR(20.9%)). Measures: VO(2max) was measured by the treadmill protocol and predicted by MSSR. Maximal heart rate (HR(max)) and maximal blood lactate concentration (BLa(max)) were recorded at the termination of each test. RESULTS: Significant correlation was observed between measured VO2(max) by the treadmill protocol (57.2+/-8.3 ml x kg(-1) x min(-1)) and predicted VO(2max) in NOR(20.9%) (54.6+/-8.0 ml x kg(-1) x min(-1)) (r=0.80, p<0.05). Also strong correlations in predicted VO(2max) between NOR(20.9%) and HYP(17.5%) (51.1+/-8.0 ml x kg(-1) x min(-1)) (r=0.90, p<0.05) and between NOR(20.9%) and HYP(15.5%) (48.1+/-7.3 ml x kg(-1) x min(-1)) (r=0.82, p<0.05) were observed. CONCLUSIONS: The results show that although MSSR underpredicts VO(2max), it is effective to evaluate aerobic power and can detect the influence of oxygen concentration on aerobic power. The specific movement of MSSR may affect the performance of LR but MSSR can describe the influence of hypoxia on the performance of LR compared to normoxia. Thus MSSR can be used to evaluate the influence of hypoxia or altitude on aerobic power as a field test.     

不同生理等效高度的富氧环境对大鼠急进高原肺水肿的防护作用

目的研究不同生理等效高度的富氧环境对大鼠急进高原肺水肿的防护作用。方法50只雄性Wistar大鼠按随机数字表法分为地面对照组、缺氧组、富氧1组、富氧2组及富氧3组,每组10只。除地面对照组外,分别将各实验组大鼠置于实验舱内,均以10m／s的速度上升至气压高度6000m,上升同时缺氧组输入空气,富氧1组和富氧2组分别输入氧浓度35％和30％的富氧气体,富氧3组则每4h交替输入空气与35％富氧气体,流量均为7L／min。24h后实验舱下降至地面,处死大鼠,测肺部含水率及病理学效应,测肺组织匀浆中的内皮素-1浓度和-氧化氮合酶活力。结果地面对照组大鼠肺含水率最低（0．80％±0．01％）,与其它各组比差异有统计学意义（P〈0．01）;缺氧组最高（0．83％±0．01％）,与地面对照组和富氧3组比差异有统计学意义（P〈0．01）;3个供氧组居中,其中富氧3组以o．81％土0．01％显著低于富氧1组和富氧2组（P〈0．05）。病理结果表明各实验组出现了不同程度肺水肿表现,由重至轻依次为缺氧组、富氧2组、富氧1组和富氧3组。内皮素-1浓度各组间差异无统计学意义。地面对照组一氧化氮合酶活力最高,为（1．49土0．24）U／mg,与其它各组比差异有统计学意义（P〈0．01）;缺氧组最低,为（0．78±0．28）U／mg,富氧1组和富氧3组一氧化氮合酶活力较强,分别为（1．06±0．17）U／mg、（1．09土0．20）U／mg,与缺氧组比较差异有统计学意义（P〈0．01）。结论在6000m停留24h后大鼠出现了高原肺水肿。氧浓度为35％富氧环境（生理等效高度约2500m）能够有效预防肺水肿,而氧浓度为30％的富氧环境（生理等效高度约3500m）防护效果不显著。4h间断供给含氧35％气体同样可以有效预防大鼠在6000m出现的高原肺水肿。     

离体淋巴细胞经低氧及低氧预处理后免疫指标的变化

目的　观察急性低氧及低氧预处理后淋巴细胞 [Ca2 ]i的变化及与淋巴细胞增殖活化的关系。　方法　取正常人外周静脉血 ,用Ficoll Hypaque密度梯度离心法分离淋巴细胞。实验分 3组 :正常对照组、急性低氧组和低氧预处理组。用Fura 2 /AM荧光分光光度法检测 [Ca2 ]i。用ELISA法检测上清液中IgG和IL 2的分泌量。用MTT法检测淋巴细胞增殖率。　结果　急性低氧后淋巴细胞 [Ca2 ]i明显下降 ,与对照组比较差异有非常显著性意义 (P <0 0 1) ,同时淋巴细胞IgG和IL 2的分泌量以及淋巴细胞增殖反应也明显下降 ,与各自的对照组相比差异有非常显著性意义(P <0 0 1) ;低氧预处理后再进行急性低氧时 ,淋巴细胞 [Ca2 ]i、IgG和IL 2的分泌量以及淋巴细胞增殖反应均恢复到与对照组相近的水平 ,且与急性低氧组比较差异有非常显著性意义 (P <0 0 1)。　结论　急性低氧后淋巴细胞免疫功能下降 ,低氧预处理能改善淋巴细胞的免疫功能 ,其中 [Ca2 ]i的适应性变化发挥了重要作用。     

间歇性低氧训练对高性能战斗机飞行员脑电复杂度及血氧饱和度的影响

目的 通过动态观察间歇性低氧训练前后高性能战斗机飞行员EEG复杂度和血氧饱和度(arterial oxygen saturation,Sa()2)的变化特征,为低氧适应性训练效果评价提供量化指标.方法 对32名高性能战斗机飞行员进行15 d的间歇性低氧训练(模拟高度3500 m),1次/d,每次25 min.于训练前后,分别检测受试者在模拟7500 m高空环境下的EEG、SaO2、红细胞数及血红蛋白含量,并对受试者低氧训练前后的检测数据进行t检验.结果 间歇性低氧训练后,受试者在模拟7500 m高空环境下的EEG复杂度较训练前显著降低,差异有统计学意义(P＜0.01),Sa()2升高,差异有统计学意义(P＜0.01),红细胞和血红蛋白含量则无明显变化(P＞0.05).结论 模拟3500 m间歇性低氧训练可提高机体高空缺氧耐力水平,EEG复杂度和SaO2可作为评价高性能战斗机飞行员间歇性低氧训练的定量生理指标. Abstract： Objective To explore the quantitative index for evaluating the intermittent hypoxia training effects by analyzing the characteristic changes of electroencephalogram (EEG) complexity and saturation of blood oxygen (SaO2) of high performance fighter pilots. Methods Thirty-two pilots were selected as subjects and undertook a 25 min-training (simulated hypoxia at 3500 m-oxygen concentration 13.1%) with Type DY-84 hypoxia training device once a day for 15 d. Before and after training the subjects were put in simulated 7500 m hypoxia condition (oxygen concentration 7.1%,ventilation volume 15L/min) and their EEG, SaO2, number of red blood cell and hemoglobin level were recorded and analyzed by t-test. Results Training effects showed that the subjects' 7500m EE(G complexity was significantly decreased (P＜0.01), but SaO2 was significantly increased (P＜0.01).Number of red blood cell and hemoglobin level had no obvious change (P＞0.05).Conclusions The simulated 3500 m intermittent hypoxia training could improve pilot's hypoxia tolerance. EEG complexity and SaO2, which are measured under simulated 7500 m hypoxia condition,would be the quantitative indices for evaluating the effects of intermittent hypoxia training for pilot.The results application would be hopefully expanded to the population who work at high altitude or in anoxic environment.     

Metabolic factors from exercising muscle and the proliferation of endothelial cells

In order to identify factors that may be involved in angiogenesis in mammalian skeletal muscle after endurance exercise, the growth of cultured vascular endothelial cells derived from the canine hindlimb was measured in response to hypoxia and changes in temperature and concentrations of hydrogen ion and adenosine. Endothelial cells were freed from vessels of exsanguinated canine hindlimbs using collagenase. Cultures were grown on plastic culture dishes at 37 degrees C and 40 torr CO2 in air. Primary cultures reached confluency by 21 days. Cell number in secondary cultures was significantly increased in 7 days by exposure to 35 torr oxygen for 1 h daily, but cell growth rate was unaffected by 65 torr oxygen. Cell growth was inhibited when hydrogen ion concentration was increased by adding lactic acid daily (5 mmol X l-1). Exposing cell cultures for 1 h daily to an elevated PCO2 (70 torr) or to an environmental temperature of 41 degrees C, adding sodium lactate (5 mmol X l-1), or adenosine (10 or 100 mumol X l-1) daily did not affect cell growth rate. Thus, hypoxia increased the growth rate of cultured vascular endothelial cells and may play a role in blood vessel growth in vivo.     

富氧吸入对大鼠模拟急性高原肺水肿的防护作用

目的 探讨富氧吸人对大鼠模拟急性高原肺水肿的防护作用.方法 将44只健康雄性Wistar大鼠随机分为4组,分别为对照组、低压低氧组、连续富氧组、夜间富氧组,每组11只.除对照组外,其余3组均置于模拟6000 m海拔高度的低压舱中48 h.富氧干预48 h后,测定各组大鼠的肺湿干比、肺泡灌洗液（bronchoalveolar lavage fluid,BALF）血清和肺组织匀浆一氧化氮（nitric oxide,NO）含量、一氧化氮合酶（nitric oxide synthase,NOS）及肺组织病理学改变.结果 与对照组相比,低压低氧组大鼠BALF蛋白浓度及肺湿干比显著升高（P＜0.01）、血清及肺组织匀浆中NO 含量、NOS降低（P＜0.01）.病理学显示低压低氧组大鼠有肺泡间隔增宽、间质充血、炎细胞浸润等间质性肺水肿表现.连续富氧及夜间富氧均可降低肺泡灌洗液的蛋白浓度及肺湿干比,提高大鼠血清和肺组织内的NO含量、NOS活性,减轻肺泡间隔增厚、炎细胞浸润及肺泡出血,且连续富氧组与夜间富氧组各项指标差异无统计学意义.结论 富氧吸人可以通过提高体内的NO含量、NOS活性来防护大鼠急进高原肺水肿,夜间富氧与连续富氧防护效果无明显差别.     

高表达低氧诱导因子-1对成骨细胞增殖及细胞周期的调控研究

目的探讨低氧情况下高表达低氧诱导因子HIF-1对成骨细胞增殖及细胞周期的影响。方法获取大鼠颌面部成骨细胞,分别在低氧含量(2%O2)、常规氧含量(21%O2)及低氧含量(2%O2)+二甲氧乙二酰甘氨酸(DMOG)条件下进行培养,在不同培养时间分别检测成骨细胞表达的增殖能力、细胞周期变化及HIF-1蛋白的表达。结果在低氧情况下,成骨细胞增殖活性降低,细胞周期分析可见处于分裂期细胞减少,加入DMOG后细胞的HIF-1蛋白处于高表达,细胞增殖特性与常规氧含量相比无统计学差异。结论 DMOG可促进低氧状态下成骨细胞低氧诱导因子-1的高表达,有利于低氧状态下成骨细胞的增殖活性回复,可加快骨生长,为骨缺损的治疗开辟了新途径。     

Temporal dynamics of lactate concentration in the human brain during acute inspiratory hypoxia

Purpose:

To demonstrate the feasibility of measuring the temporal dynamics of cerebral lactate concentration and examine these dynamics in human subjects using magnetic resonance spectroscopy (MRS) during hypoxia.

Materials and Methods:

A respiratory protocol consisting of 10‐minute baseline normoxia, 20‐minute inspiratory hypoxia, and ending with 10‐minute normoxic recovery was used, throughout which lactate‐edited MRS was performed. This was repeated four times in three subjects. A separate session was performed to measure blood lactate. Impulse response functions using end‐tidal oxygen and blood lactate as system inputs and cerebral lactate as the system output were examined to describe the dynamics of the cerebral lactate response to a hypoxic challenge.

Results:

The average lactate increase was 20% ± 15% during the last half of the hypoxic challenge. Significant changes in cerebral lactate concentration were observed after 400 seconds. The average relative increase in blood lactate was 188% ± 95%. The temporal dynamics of cerebral lactate concentration was reproducibly demonstrated with 200‐second time bins of MRS data (coefficient of variation 0.063 ± 0.035 between time bins in normoxia). The across‐subject coefficient of variation was 0.333.

Conclusion:

The methods for measuring the dynamics of the cerebral lactate response developed here would be useful to further investigate the brain's response to hypoxia. J. Magn. Reson. Imaging 2013;37:739–745. © 2012 Wiley Periodicals, Inc.