ObjectiveTo observe the effects of A549 cells under hypoxicconditions on the migration of human umbilical vein endothelial cells (HUVECs) and microvascular formation. MethodsAfter cultured for 24 h in normoxia condition(21% O2),hypoxia condition (2% O2),and anaerobic condition (0% O2),respectively,morphology of A549 cells was observed with inverted phase contrast microscope,proliferation was detected by MTT assay,and intracellular hypoxia-inducible factor-1α (HIF-1α) protein was detected by immunocyto-chemical technique,for determining whether the hypoxia model is successful. Then A549 cells' supernatant in the normoxic group,the hypoxia group and HUVECs culture medium were taken to intervene HUVECs. The migration of HUVECs was observed with cell scratch test,pseudopodia formation of HUVECs was observed with microfilament green fluorescent staining method,and blood vessel formation was observed with three-dimensional culture techniques in vitro. ResultsCompared with the normoxic group,the growth of A549 cells was better in the hypoxia group with more proliferation,and was poor in the anaerobic group with decreased number of cells. A549 cells in the hypoxia group and the anaerobic group both expressed HIF-1α protein,which was more obvious in the anaerobic group. Compared with the HUVECs supernatant intervention group,the hypoxia supernatant intervention group and the normoxic supernatant intervention group both had varying degrees of migration,pseudopodia structure formation and vascular lumen sample structure formation,which were more obvious in the former group. ConclusionA549 cells in hypoxic environment grow very well,proliferated significantly,but anaerobic environment is not conducive to the growth of A549 cells which found to be apoptosis. A549 cells in hypoxic environment can promote HUVECs migration,pseudopodia formation and angiogenesis.
目的：采用常压间歇性低氧(intermittent hypoxia,IH)大鼠的动物模型，观察间歇性常压低氧预处理的促血管生成作用。方法:成年雄性Wistar大鼠25只，体重210～215 g，随机分为2大组:对照组(C组，n=5)和间歇性低氧预处理组(IH组，n=20)。IH组动物进行间歇性低氧预处理(4 h/d，间歇缺氧1 d者为IH1组，7 d者为IH2组，14 d者为IH3组，28 d者为IH4组)，按计划完成实验后测定心肌血管内皮生长因子(VEGF) 蛋白表达及毛细血管密度。结果：间歇性低氧预处理大鼠心肌VEGF蛋白表达增加，心肌毛细血管密度增高。结论：间歇性低氧预处理能促进大鼠心肌内的血管生成，其机制可能与心肌VEGF表达增高有关。
Objective To construct the responsive plasmid PTRE-HIF-1αof Tet-on gene expression system and examine its expression. Methods RT-nested PCR was performed on the total RNA extracted from hypoxia HepG2 cells to obtain the cDNA of HIF-1α, which was inserted into the responsive plasmid PTRE2hyg. DNA sequencing was performed after the recombinant of responsive plasmid PTRE-HIF-1α was identified by endonuclease digestion. This recombinant vector was transfected into HepG2Tet-on cells by means of liposome and its expression was examined by RT-PCR and Western blot under the control of deoxycycline. Results The amplified products were confirmed as the cDNA of HIF-1α by DNA sequencing. The responsive plasmid PTRE-HIF-1α verified by edonuclease digestion, was capable of expression in HepG2Tet-on cells and could be controlled by deoxycycline. Conclusion The responsive plasmid PTRE-HIF-1α of Tet-on expression system is constructed successfully, and it can express under the regulation of deoxycycline in the HepG2Tet-on cells.
To evaluate the development prevention and treatment of pneumonic injury after operation on aged patients with abdominal infection. We analyzed 77 aged patients (＞60 y) admitted from Jan. 1991 to Dec. 1992: 38 cases of which with abdominal infection (infection group), 39 cases without abdominal infection (non-infection group). All patients were given oxygen therapy and continuous SaO2 monitoring. Results: There were 28 patients with hypoxemia (SaO2＜95%) in infection group, with an occurrence rate of 73.7%. In non-infection group (12 patients), the rate of hyoxemia was 30.8%, which has significant difference between two groups (Ｐ＜0.001). All patients with hypoxemia were given oxygen therapy and 31 patients′ SaO2 was elevated. The efficient rate was 77.5%. Other 9 patients developed ARDS, the rate was 2.5% (9/40). In the infection group 8 patients developed ARDS with an occurrence rate of 21.1%. There was one patient with ARDS in the non-infection group, the rate was 2.6%. There was significant difference between two group (Ｐ＜0.05). Conclusions: The results suggest that hypoxemia is liable to occur in aged patients with abdominal infection after operation and these patients were liable to develop ARDS. Oxygen therapy and SaO2 monitoring is the important managements to these patients in prevention of pneumonic injury.
Objective To investigate the preventive effect of simvastatin，a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor，on hypoxic pulmonary hypertension and the relation between it and the angiotensin Ⅱ receptor-1（AT1R） expression in pulmonary arteriole.Methods Thirty male Sprague-Drawley rats were randomly allocated into three groups：a control group，a hypoxic group and a simvastatin preventive group.The animal model of hypoxic pulmonary hypertension was established by exposing the rats to normobaric hypoxic condition（8 h×6 d×3 w），and the preventive group were treated with simvastatin 10 mg/kg before hypoxic processing while the control and hypoxic groups were treated with sodium chloride.The mean pulmonary pressure（mPAP），serum cholesterol concentration，right ventricular hypertrophy index [RV/（LV+S）]，percentage of the wall thickness in the external diameter（WT%），percentage of the wall area in the total vascular area（WA%），and the AT1R expression in pulmonary arterioles were measured.Results When compared with the hypoxic group，in the preventive group，the mPAP and RV/（LV+S）obviously reduced [（22.6±3.86）mm Hg vs （29.3±2.27）mm Hg，（25.13±0.75）% vs （33.18±1.58）%，Plt;0.01 respectively]，the indices of wall thickness of rat pulmonary arteriole and area also decreased significantly [WT%：（15.98±1.96）% vs （25.14±1.85）%；WA%：（54.60±3.94）% vs 74.77±4.52）%；Plt;0.01 respectively]，and the positive degree of AT1R still lessened noticeably（1.23±0.09 vs 1.57±0.13，Plt;0.01）.All of the indices above in the hypoxic group increased markedly compared with the control group（Plt;0.01 respectively）.However，the differences of serum cholesterol among three groups were not significant（Pgt;0.05）.Conclusions Simvastatin can suppress the expression of AT1R in pulmonary vessel and prevent hypoxic pulmonary hypertension.
在过去二十年间，麻醉技术和手术技术的改进使肺部恶性肿瘤患者的手术死亡率大大降低，但术后并发症仍是主要问题。肺切除术后的常见并发症是肺部并发症[1]，主要表现是低氧血症，尤其在肺功能减退的肺切除患者中发病率更高[2]。目前国内对低氧血症的诊断缺乏统一的诊断标准，一些作者采用Russell等[3]提出的标准，吸空气氧的情况下，患者动脉血氧饱和度（SpO2）≤92%，大于30 s就可诊断为术后低氧血症。也有作者建议[4]将一次或以上血气检查PaO2lt;8 kPa或PaO2/FiO2lt;300 mm Hg（1 mm Hg=0.133 kPa）作为诊断低氧血症的标准。30%~50%的术后患者可发生低氧血症，一般认为这样的低氧血症是一过性的，对大多数患者是无害的[5]。但如果合并心脑或其他器官动脉硬化或其他原因的血管阻塞，这种低氧血症就是很危险的[6]。常见低氧血症的原因是肺萎陷不张和误吸、心源性肺水肿、静脉输入液体过量、通气血流比例失调和急性肺损伤/急性呼吸窘迫综合征（ALI/ARDS）[7]，其中ALI/ARDS是肺切除术后患者死亡的主要原因[8-10]。
Objective To investigate the influence of hypoxic preconditioning on pulmonary structure of rats exposed to simulated high altitude hypoxia and to explore the role of hypoxia inducible factor-1α（HIF-1α）.Methods Fifty-six Wistar rats were randomly divided into 7 groups(n=8 in each group),ie,a normal control group(N group)，an acute hypoxic control group(H0 group)，an acute hypoxic group(H1 group)，a 3 000 m hypoxic preconditioning group(C3.0 group)，a 3 000 m hypoxic preconditioning + acute hypoxic group (C3.1 group)，a 5 000 m hypoxic preconditioning group(C5.0 group)，and a 5 000 m hypoxic preconditioning + acute hypoxic group(C5.1 group).After treated with hypoxic preconditioning，the animals were exposed to simulated altitude of 6 000 m for 24 hours.Then the protein and mRNA expression of HIF-1α in lung of N，H0，C3.0 and C5.0 groups were assessed by Western blot and RT-PCR，respectively.The lung structure in N，H1，C3.1 and C5.1 groups was observed by light microscope and electron microscope.Results Pulmonary interstitial edema was apparently observed in H1 group，while significantly relieved in two hypoxic preconditioning groups.HIF-1α protein was not detected in rat lungs by Western blot analysis.Compared to N group，the levels of HIF-1α mRNA significantly increased in C3.0 group and C5.0 group(both Plt;0.01).Conclusions Hypoxic preconditioning can relieve hypoxic pulmonary interstitial edema and increase HIF-1α mRNA expression in rat lungs.HIF-1 may be involved in the process of hypoxic preconditioning in rat lungs.
单肺通气技术( OLV) 广泛应用于开胸手术, 该技术使手术侧肺萎陷, 非手术侧单肺通气, 目的是防止手术侧肺分泌物或血液流入健侧肺, 确保气道通畅, 防止交叉感染, 避免手术侧肺膨胀, 使肺保持安静以利于手术操作, 减轻对肺实质的损伤。随着手术日益走向微创时代, 对该技术的需求大量增加。
Objective To develope a novel rabbit carotid body and carotid common artery model in vivo for the simulation of various intermittent hypoxia ( IH) intensities, IH durations, IH reoxygenation ( ROX) durations and continuous hypoxia ( CH) modes. Methods Forty-five adult New Zealand rabbits ( 2. 5-3. 0 kg) were anesthetized while spontaneous breathing kept intact. The tissue surrounding the right carotid common artery and carotid sinus nerve ( CSN) were cleared and " single" chemoreceptor bundle of the CSN was revealed. Then suction electrodes were placed and CSN afferent activity was monitored and recorded carefully. The right common carotid artery was exposed, cannulated to distal part and its proximal part was ligated. Preparations were challenged by changing the PO2 of the gas mixture equilibrating the perfusate. Alternatively perfusion ( 2 mL/min) of equilibrated perfusate bubbled with normoxia or hypoxia gas mixtures formed IH/ROX cycles in carotid common artery, simulating the pattern of hypoxic episodes seen in obstructive sleep apnea syndrome ( OSAS) , or with continuously perfusing hypoxia perfusate to form CH modes. All the perfusing procedures were regulated by a customized computer-controlled set and monitored using O2 gas analyzer. After the systematic exposures, carotid body, carotid common artery part distal to cannula, and carotid bifurcation were harvested as samples. Results The frequencies and average amplitudes of CSN chemoreceptor bundles afferent activities with normoxia perfusion were ( 0. 17 ±0. 03) impulse/ s and ( 46. 2 ±4. 4) μV, and with hypoxia perfusion were ( 0. 64 ±0. 09) impulse/ s and ( 87. 4 ±6. 6) μV, respectively. PO2 was ( 139 ±1. 5) mm Hg in normoxia perfusate and ( 35. 2 ±1. 3) mm Hg in hypoxia perfusate. Conclusion This new carotid body and carotid common arterymodel is a valuable tool to study neurological and biochemical changes in various IH and CH modes.
Objective To observe the effects of peritoneal ventilation with pure oxygen in the rabbits with hypoxaemia and hypercapnia induced by mechanical controlled hypoventilation. Methods Sixteen rabbits were invasively ventilated after trachea incision. Hypoxaemia and hypercapnia were induced by hypoventilation which was implemented both by degrading ventilation parameters and respiratory depression induced by intravenous infusion of muscle relaxant. Then pure oxygen was insufflated into the peritoneal cavity and arterial blood gases were measured every 30 minutes for two hours. Results The PaO2 was ( 52. 50 ±3. 46) mmHg at baseline and increased to ( 76. 46 ±7. 79) mm Hg, ( 79. 62 ±9. 53) mm Hg,( 78. 54 ±7. 18) mmHg, and ( 81. 1 ±8. 3) mm Hg, respectively at 30, 60, 90, and 120 minutes after the peritoneal ventilation with pure oxgen( all P lt; 0. 05) . Meanwhile PaCO2 was ( 63. 84 ±9. 09) mm Hg at baseline and ( 59. 84 ±14. 22) mmHg, ( 59. 16 ±15. 5) mmHg, ( 60. 02 ±7. 07) mmHg, and ( 61. 38 ±6. 56) mm Hg, respectively at 30, 60, 90, and 120 minutes after the peritoneal ventilation with pure oxgen with no significant change( P gt;0. 05) . Conclusion Peritoneal ventilation can obviously improve hypoxaemia induced by mechanical controlled hypoventilation, whereas hypercapnia remains unchanged.