Baicalin prevents the up-regulation of connective tissue growth factor in fibrotic lungs of rats

To clarify the mechanism underlying the preventive effect of baicalin (Bai) on fibrosis in lung, we investigated the influence of Bai on the up-regulation of connective tissue growth factor (CTGF) in fibrotic lungs. Male Sprague-Dawley (SD) rats were divided into four groups randomly: normal saline (NS)+NS group (a single intratracheal instillation of NS plus i.p. injection of NS), NS+Bai group (intratracheal instillation of NS plus i.p. injection of Bai), bleomycin (BLM)+NS group (intratracheal instillation of BLM plus i.p. injection of NS) and BLM+Bai group (intratracheal instillation of BLM plus i.p. injection of Bai). All the i.p. injections were performed once daily. On day 28 after intratracheal instillation of BLM or NS, the rats were sacrificed for lung tissue sampling. As the index of the severity of pulmonary fibrosis, the content of hydroxyproline in lungs was analyzed by chloramine T method. The expression levels of CTGF mRNA and protein in the lungs were detected by RT-PCR and immunohistochemistry, respectively. The results showed that, compared to the rats in NS+NS group, the rats in BLM+NS group showed increased hydroxyproline content and higher levels of CTGF mRNA and protein expressions (P<0.01), suggesting that BLM had induced fibrosis in lung and up-regulated CTGF expression in the fibrotic lungs. Administration of different dosages of Bai (6, 12.5 and 50 mg/kg per d, for 28 days) into the BLM-treated rats reduced the increased content of hydroxyproline, and ameliorated the up-regulation of CTGF mRNA and protein levels, respectively. These results suggest that Bai could prevent the up-regulation of CTGF expression in fibrotic lungs of rats receiving BLM instillation, which might be one of the mechanisms underlying the preventive effect of Bai on pulmonary fibrosis.     

Adrenomedullin ameliorates lipopolysaccharide-induced acute lung injury in rats

Adrenomedullin (AM), an endogenous peptide, has been shown to have a variety of protective effects on the cardiovascular system. However, the effect of AM on acute lung injury remains unknown. Accordingly, we investigated whether AM infusion ameliorates lipopolysaccharide (LPS)-induced acute lung injury in rats. Rats were randomized to receive continuous intravenous infusion of AM (0.1 microg x kg(-1) x min(-1)) or vehicle through a microosmotic pump. The animals were intratracheally injected with either LPS (1 mg/kg) or saline. At 6 and 18 h after intratracheal instillation, we performed histological examination and bronchoalveolar lavage and assessed the lung wet/dry weight ratio as an index of acute lung injury. Then we measured the numbers of total cells and neutrophils and the levels of tumor necrosis factor (TNF)-alpha and cytokine-induced neutrophil chemoattractant (CINC) in bronchoalveolar lavage fluid (BALF). In addition, we evaluated BALF total protein and albumin levels as indexes of lung permeability. LPS instillation caused severe acute lung injury, as indicated by the histological findings and the lung wet/dry weight ratio. However, AM infusion attenuated these LPS-induced abnormalities. AM decreased the numbers of total cells and neutrophils and the levels of TNF-alpha and CINC in BALF. AM also reduced BALF total protein and albumin levels. In addition, AM significantly suppressed apoptosis of alveolar wall cells as indicated by cleaved caspase-3 staining. In conclusion, continuous infusion of AM ameliorated LPS-induced acute lung injury in rats. This beneficial effect of AM on acute lung injury may be mediated by inhibition of inflammation, hyperpermeability, and alveolar wall cell apoptosis.     

大鼠肺纤维化形成中肺内肥大细胞结缔组织生长因子的表达

目的：观察博莱霉素（BLM）诱导肺纤维化形成中肺肥大细胞（MCs）是否表达结缔组织生长因子（CTGF）。方法：32只雄性SD大鼠,随机分为博莱霉素（BLM）组和对照（Control）组（n=16）。BLM组为气管内一次性滴注BLM（5mg／ks）;Control组为气管内滴注与BLM等容量的生理盐水（NS）。各组分别在气管滴注后第14天和第28天处死大鼠,取肺组织样本。用氯胺-T法检测肺组织羟脯氨酸含量以判断肺纤维化程度;用甲苯胺蓝染色显示肺组织切片中的MCs;免疫组化染色显示肺CTGF的表达和分布。结果：①与对照大鼠比,气管内滴注BLM后第28天大鼠的肺羟脯氨酸含量明显增高（P〈0．01）。②与对照大鼠比,气管内滴注BLM后第14天和第28天大鼠肺内MCs数明显增多（均P〈0．01）,肺内CTGF表达上调（均P〈0．01）。③对照大鼠肺内未见CTGF免疫阳性的MCs;而气管内滴注BLM后第14天和第28天大鼠肺内病灶区中有CTGF免疫阳性的MCs。结论：肺纤维化形成中肺MCs表达CTGF,这可能是MCs促进肺纤维化的作用机制之一。     

Effect of recombinant SP-C surfactant in a porcine lavage model of acute lung injury.

Synthetic surfactants allow examination of the effects of specific components of natural surfactant. To determine whether surfactant containing apoprotein C, dipalmitoyl-phosphatidylcholine, phosphatidylglycerol, and palmitic acid restores gas-exchanging function in acute lung injury (ALI), we administered such surfactant (in doses of 50 or 100 mg/kg and in volumes from 1 to 6 ml/kg) or phospholipid (PL) alone, by intratracheal instillation, to pigs with ALI induced by massive saline lavage. Animals ventilated with 100% O(2) and receiving 1, 2, 4, or 6 ml/kg of 50 mg/kg recombinant surfactant apoprotein C (rSP-C) surfactant or 2 ml/kg of 50 mg/kg PL (control) had mean arterial PO(2) values, 4 h after treatment, of 230, 332, 130, 142, or 86 Torr, respectively. Animals receiving 1, 2, or 4 ml/kg of 100 mg/kg rSP-C surfactant or 2 ml/kg of 100 mg/kg PL (control) had mean arterial PO(2) values of 197, 214, 148, or 88 Torr, respectively. Surfactant PL distribution was homogeneous. Hyaline membrane formation was reduced in treated animals. Thus, in this model of ALI, rSP-C with PL has the capacity to improve gas exchange and possibly modify lung injury.     

Pulmonary gemcitabine delivery for treating lung cancer: pharmacokinetics and acute lung injury aspects in animals

Gemcitabine, a nucleoside analogue for treating lung cancer, is clinically administered as an intravenous infusion. To achieve better patient compliance and more direct effect on the lung, we explored a new gemcitabine pulmonary delivery route and evaluated the pharmacokinetics and acute lung injury aspects in animals. Pharmacokinetics of gemcitabine were measured in Sprague-Dawley rats after intravenous (i.v.), intratracheal instillation by tracheotomy (i.t.t.), intratracheal instillation via orotrachea (i.t.o.), and intragastric (i.g.) administration of gemcitabine. Acute lung injury effects of the pulmonary delivery of gemcitabine were performed in Sprague-Dawley rats after i.t.o. and i.v. administration of gemcitabine and i.t.o. administration of lipopolysaccharide (LPS) as a positive control and physiological saline as a blank control. Indicators for acute lung injury that were evaluated included lung morphology, lung histopathology, lung coefficient, lung wet/dry weight ratio, total cell and classification counts in bronchoalveolar lavage cells (BALC), and total protein and TNF-alpha levels in bronchoalveolar lavage fluids (BALF). After i.t.t. or i.t.o. administration, gemcitabine was quickly absorbed, but i.g. administration led to an undetectable plasma gemcitabine concentration. Absolute bioavailability of gemcitabine after i.t.t. and i.t.o. administration was 91% and 65%, respectively. Gemcitabine given as i.t.o. administration did not cause any overt acute lung injury. All indicators for acute lung injury in the i.t.o. group were similar to those in the i.v. group or in the blank control, but significantly different from those in the positive control. In conclusion, the pharmacokinetics and acute lung injury studies suggest that pulmonary gemcitabine delivery would be a new and promising administration route.     

Abatement of bleomycin-induced pulmonary injury by cell-impermeable inhibitor of phospholipase A2

The mechanism of bleomycin (Bleo)-induced pulmonary injury is not fully understood. Elevated levels of lung phospholipase A₂ (PLA₂) have been previously reported following intratracheal (IT) instillation of Bleo, but the role of this enzyme in the pathogenesis of lung injury is not clear.In this pilot study, we have evaluated the effect of a cell impermeable inhibitor of PLA₂ (CME) on Bleo-induced pulmonary inflammation in hamsters. Pulmonary injury was induced by a single IT instillation of Bleo (1 unit/0.5 ml saline). Three groups of male Syrian hamsters were evaluated: 1) BLEO-CME animals received IT Bleo and daily intraperitoneal (IP) injections of CME (1 μmole/kg), starting 1 day before IT instillation; 2) BLEO-SAL animals-received IT Bleo and IP injections of saline and 3) SAL-SAL animals — treated with IT and IP administrations of saline. Animals were sacrificed 14 days after IT treatment and lung injury was evaluated histologically by a semiquantitative morphologic index and by a differential cell count of bronchoalveolar lavage fluid. CME treatment significantly ameliorated Bleo-induced lung injury compared to BLEO-SAL animals (P < 0.05). The percentage of neutrophiles in bronchoalveolar lavage fluid was reduced from 17.7 ± 3.2% (mean ± S.E.) in BLEO-SAL group to 7.3 ± 1.7% in BLEO-CME group (P < 0.05), achieving levels comparable to SAL-SAL control animals. These results suggest that treatment with an extracellular PLA₂ inhibitor-CME abates Bleo-induced pulmonary injury. This may indicate an active role of PLA₂ in the pathogenesis of interstitial pulmonary fibrosis.     

Dose response to rhCC10-augmented surfactant therapy in a lamb model of infant respiratory distress syndrome: physiological, inflammatory, and kinetic profiles.

While surfactant (SF) therapy alone improves respiratory distress syndrome (RDS)-associated gas exchange and lung stability, absence of anti-inflammatory proteins limits efficacy with respect to inflammation. Clara cell secretory protein (CC10), deficient in preterm infants, prevents SF degradation and has anti-inflammatory properties. In this study, intratracheal recombinant human (rh) CC10 (Claragen)-augmented SF (Survanta, Ross) therapy was examined in a premature lamb model of RDS with respect to inflammation and kinetic dose-response profiles. Preterm lambs (n = 24; gestational age: 126 +/- 3 days) were delivered via cesarean section, sedated, ventilated, and randomized into groups: 100 mg/kg SF, 100 mg/kg SF followed by 0.5 mg/kg rhCC10, 100 mg/kg SF followed by 1.5 mg/kg rhCC10, and 100 mg/kg SF followed by 5.0 mg/kg rhCC10. Arterial blood chemistry and lung mechanics were monitored; lungs were lavaged and snap-frozen after 4 h. TNF-alpha, IL-8 in plasma; TNF-alpha, IL-6, IL-8, myeloperoxidase in lung; and rhCC10 in plasma, urine, bronchoalveolar lavage, and lung were analyzed. Improvement in compliance, peak inspiratory pressure, and ventilatory efficiency index were greatest (P < 0.05) with SF + 5.0 mg/kg rhCC10. Plasma, urine, bronchoalveolar lavage, and lung [rhCC10] (where brackets denote concentration) increased (P < 0.01) with dose. Plasma [IL-8] was lower (P < 0.05) with rhCC10 than SF alone. Treatment with at least 1.5 mg/kg rhCC10 resulted in lower (P < 0.05) lung [TNF-alpha], [IL-8], and [myeloperoxidase]; SF + 1.5 mg/kg rhCC10 group had lower (P < 0.05) lung [IL-6], compared with all other groups. Compared with SF alone, SF augmented with at least 1.5 mg/kg rhCC10 decreased RDS-induced lung and systemic inflammation. Given that inflammation may lead to functional compromise, these data suggest that early intervention with rhCC10 may enhance SF therapy and warrant longer duration studies to determine its role to decrease long-term complications of ventilator management.     

Halofuginone does not reduce fibrosis in bleomycin-induced lung injury

Halofuginone, a coccidiostatic alkaloid, has anti-fibrotic properties, and may be useful as a therapeutic agent in lung fibrosis. To test this hypothesis we investigated the effect of halofuginone on bleomycin-induced lung fibrosis in Sprague-Dawley rats. Treatment groups included: (1) a single intratracheal (IT) instillation of 1.2U bleomycin, and intraperitoneal (IP) injection of halofuginone (0.5 mg/dose), every other day; (2) IT 1.2U bleomycin and IP distilled water (D.W.), every other day; (3) IT 0.8U bleomycin and daily IP halofuginone (0.5 mg/dose); (4) IT 0.8U bleomycin and daily IP D.W.; (5) IT saline and IP halofuginone, every other day; (6) IT saline and daily IP D.W.; (7) IT 0.625U bleomycin and oral halofuginone (10 mg/kg rodent lab chow); (8) IT 0.625U bleomycin and standard lab chow. Animals were studied 14 days after IT instillation. Lung injury was evaluated by total and differential cell count in bronchoalveolar lavage fluid, by a semi-quantitative morphological index of lung injury, and by biochemical analysis of lung hydroxyproline content. Overt signs of lung injury were apparent in bleomycin-treated rats by all measures. These changes were not affected by treatment with halofuginone, irrespective of the treatment regimen used. This study does not support the use of halofuginone to prevent or ameliorate lung fibrosis.     

内毒素诱导大鼠急性肺损伤模型的动态研究

目的:建立内毒素诱导大鼠急性肺损伤的模型并筛选出敏感检测指标。方法:90只wistar大鼠随机分为10组,其中9组以气管内滴注内毒素(Lipopolysaccharide,LPS)建立大鼠急性肺损伤(Acute lung injury,ALI)模型,另一组作为空白对照组。观察造模8、12、24、36、48、72、96、120 h后的肺泡灌洗液(BALF)中肿瘤坏死因子-α(TNF-α)、白介素-6(IL-6)水平、肺组织的病理形态学变化、12h造模组与空白组的BALF中的多形核白细胞(PMN)百分比和蛋白浓度。结果:造模后BALF中的TNF-α、IL-6的浓度随时间延长显著升高且均在24 h达到峰值(P0.01);肺组织病理损伤也逐渐加重,12 h已出现明显的肺泡损伤、肺水肿、炎性细胞浸润等病变;12 h模型组BALF中PMN百分比和蛋白浓度较空白对照组显著增加(P0.01)。结论:在该实验条件下,气管内滴注LPS 8 mg/kg,12 h后即可建立ALI模型,可通过检测BALF中的TNF-α、IL-6浓度及肺组织的病变程度等指标进行模型评价。     

Neutrophil defensins mediate acute inflammatory response and lung dysfunction in dose-related fashion

High concentrations of neutrophil defensins from airway and blood have been reported in patients with inflammatory lung diseases, but their exact role is unclear. We investigated the direct effect of defensins on the lungs of mice. Intratracheal instillation of purified defensins (5-30 mg/kg) induced a progressive reduction in peripheral arterial O(2) saturation, increased lung permeability, and enhanced the lung cytochrome c content. These indexes of acute lung dysfunction were associated with an increased total cell number and a significant neutrophil influx into the lung [5.1 +/- 0.04% in control vs. 48.6 +/- 12.7% in the defensin (30 mg/kg) group, P < 0.05]. Elastase concentrations in the bronchoalveolar lavage (BAL) fluids increased from 38 +/- 11 ng/ml (control) to 80 +/- 4 ng/ml (defensins, P < 0.05). Five hours after defensin instillation, concentrations of tumor necrosis factor-alpha and macrophage inflammatory protein-2 in BAL fluid were significantly increased. High levels of monocyte chemoattractant protein-1 in BAL fluid and plasma were also found after defensin stimulation. We conclude that intratracheal instillation of defensins causes acute lung inflammation and dysfunction, suggesting that high concentrations of defensins in the airways may play an important role in the pathogenesis of inflammatory lung diseases.     

Effects of taurine on bleomycin-induced lung fibrosis in hamsters

Four groups of hamsters were assigned as saline + saline, taurine + saline (TS), saline + bleomycin (SB), and taurine + bleomycin (TB). The animals were treated with either saline or taurine (500 mg/kg ip) for 1 week and just prior to intratracheal instillation of bleomycin (7.5 units/kg) or saline on the eighth day. Thereafter, taurine administration was continued ip (250 mg/kg) and in drinking water (1%) for another 14 days. Bleomycin-induced increases in lung collagen were significantly inhibited in TB hamsters. Plasma taurine concentration in the TS group was significantly higher than that of the other groups. Lung lavage (bronchoalveolar lavage fluid) taurine in the SB group was significantly higher than the saline + saline and TS groups. Bronchoalveolar lavage fluid supernatant protein and acid phosphatase levels in the SB and TB groups were significantly increased over the saline + saline and TS groups. Although the total number of cells recovered in bronchoalveolar lavage fluid was not different among the four groups, there were significantly fewer neutrophils in the TB as compared with SB hamsters. Morphometric analysis revealed less than half as much lesion (diffuse mononuclear alveolitis and multifocal fibroplasia) in TB as compared with SB hamsters. Also, consolidated foci were less frequent and smaller in TB as compared with SB hamsters. Taurine may attenuate bleomycin-induced inflammation and fibrosis by scavenging reactive oxygen metabolites.     

Protective effect of lung inflation in reperfusion-induced lung microvascular injury

We used the isolated-perfused rat lung model to study the influence of pulmonary ventilation and surfactant instillation on the development of postreperfusion lung microvascular injury. We hypothesized that the state of lung inflation during ischemia contributes to the development of the injury during reperfusion. Pulmonary microvascular injury was assessed by continuously monitoring the wet lung weight and measuring the vessel wall (125)I-labeled albumin ((125)I-albumin) permeability-surface area product (PS). Sprague-Dawley rats (n = 24) were divided into one control group and five experimental groups (n = 4 rats per group). Control lungs were continuously ventilated with 20% O(2) and perfused for 120 min. All lung preparations were ventilated with 20% O(2) before the ischemia period and during the reperfusion period. The various groups differed only in the ventilatory gas mixtures used during the flow cessation: group I, ventilated with 20% O(2); group II, ventilated with 100% N(2); group III, lungs remained collapsed and unventilated; group IV, same as group III but pretreated with surfactant (4 ml/kg) instilled into the airway; and group V, same as group III but saline (4 ml/kg) was instilled into the airway. Control lungs remained isogravimetric with baseline (125)I-albumin PS value of 4.9 +/- 0.3 x 10(-3) ml x min(-1) x g wet lung wt(-1). Lung wet weight in group III increased by 1.45 +/- 0.35 g and albumin PS increased to 17.7 +/- 2.3 x 10(-3), indicating development of vascular injury during the reperfusion period. Lung wet weight and albumin PS did not increase in groups I and II, indicating that ventilation by either 20% O(2) or 100% N(2) prevented vascular injury. Pretreatment of collapsed lungs with surfactant before cessation of flow also prevented the vascular injury, whereas pretreatment with saline vehicle had no effect. These results indicate that the state of lung inflation during ischemia (irrespective of gas mixture used) and supplementation of surfactant prevent reperfusion-induced lung microvascular injury.     

Supplementation with vitamins C and E improves mouse lung repair

Cigarette smoke (CS) induces emphysema by tissue destruction through the production of oxidants and metalloproteinases [matrix metalloproteinases (MMPs)]. The possibility of lung repair after emphysema remains unclear. Our aim was to study the effects of vitamins C and E on mouse lung repair evaluated by catalase (CAT), superoxide dismutase (SOD) and MMP-9 activities; by the amount of tumor necrosis factor (TNF)-alpha in lung homogenates; by cell quantification in bronchoalveolar lavage (BAL) fluid; and by lung histology. Male C57BL/6 mice (n=25) were exposed to nine cigarettes per day, 7 days/week, for 60 days in a whole-body exposure chamber. The control group was sham smoked (n=10). After 60 days of CS exposure, a group of animals was sacrificed (n=5) and the others were divided into two groups: (a) CSv (n=10) supplemented with saline and olive oil (vehicles) for 60 days and (b) CSr (n=10) supplemented with vitamins C and E (50 mg/kg/day) for 60 days. These mice were then sacrificed; BAL was performed and the lungs were removed for biochemical and histological analysis. The results demonstrated that CAT activity was decreased in the CSv and CSr groups compared to the control group. SOD activity was higher in the CSv group than in the control and CSr groups. The CSv group showed a higher neutrophil count in BAL fluid, associated with more TNF-alpha in lung homogenates, than the control or CSr groups. Finally, emphysema in the CSv group was associated with fewer collagen and elastic fibers than in the control and CSr groups. These results indicate a possible role of vitamins C and E in lung repair after emphysema induced by long-term CS exposure in mice.     

Influence of refractory ceramic fibres - asbestos substitute - on the selected parameters of bronchoalveolar lavage 6 months after intratracheal instillation to W-rats

Industrial fibrous dusts are applied in many industrial branches and represent adverse factors in occupational and environmental area. Refractory ceramic fibers (RCFs) - amorphous alumina silicates - are used as one kind of asbestos substitutes. Because RCFs are relatively durable and some RCFs are respirable, they may present a potential health hazard by inhalation. The aim of present work was to find out the subchronic effect of RCFs on selected parameters of bronchoalveolar lavage (BAL) in W-rats, confirm the biopersistence of RCFs after 6 month instillation and contribute to the understanding of the pathomechanism of lung injury after fibrous dust exposure. Wistar rats were intratracheally instilled with 4 mg/animal of RCFs - exposed group and with 0.4 ml saline solution/animal - control group. Animals were sacrificed after 6 month exposure. Bronchoalveolar lavage (BAL) was performed and selected BAL parameters (mainly inflammatory and cytotoxic) were examined. After treatment with RCFs the following changes were observed: statistically significant increase in proportion of lymphocytes and polymorphonuclears as well as in % of immature alveolar macrophages (AM) and phagocytic activity of AM; statistically significant decrease in viability of AM and proportion of AM (from the differential cell count) in comparison with the control group. The results of this study indicated that RCFs even 6 months after intratracheal instillation very significantly changed the majority of examined BAL parameters. The presence of inflammatory and cytotoxic response in lung may signalize beginning or developing disease process.     

Fas-mediated acute lung injury requires fas expression on nonmyeloid cells of the lung

Fas (CD95) is a membrane surface receptor, which, in the lungs, is expressed in macrophages, neutrophils, and epithelial cells. In mice, Fas activation leads to a form of lung injury characterized by increased alveolar permeability. We investigated whether Fas-mediated lung injury occurs primarily as a result of Fas activation in myeloid cells (such as macrophages) or in nonmyeloid cells (such as epithelial cells). Chimeric mice lacking Fas in either myeloid or nonmyeloid cells were generated by transplanting marrow cells from lpr mice (which lack Fas) into lethally irradiated C57BL/6 mice (MyFas(-) group) or vice versa (MyFas(+) group). Additional mice transplanted with marrow cells from their same strain served as controls (Fas(+) ctr and Fas(-) ctr groups). Sixty days after transplantation, the mice received intratracheal instillations of the Fas-activating mAb Jo2 (n = 10/group), or an isotype control Ab (n = 10/group), and were euthanized 24-h later. Only animals expressing Fas in nonmyeloid cells (Fas(+) ctr and MyFas(-)) showed significant increases in lung neutrophil content and in alveolar permeability. These same mice showed tissue evidence of lung injury and caspase-3 activation in cells of the alveolar walls. Despite differences in the neutrophilic response and lung injury, there was no statistical difference in the lung cytokine concentrations (KC and MIP-2) among groups. We conclude that Fas-mediated lung injury requires expression of Fas on nonmyeloid cells of the lungs. These findings suggest that the alveolar epithelium is the primary target of Fas-mediated acute lung injury, and demonstrate that apoptotic processes may be associated with neutrophilic inflammation.     

MiRNA-26b inhibits the proliferation,migration, and epithelial–mesenchymal transition of lens epithelial cells

In the present study we investigated the effects of lung injury on energy metabolism (succinate dehydrogenase, complex II, cytochrome c oxidase, and ATP levels), respiratory mechanics (dynamic and static compliance, elastance and respiratory system resistance) in the lungs of rats, as well as on phospholipids in bronchoalveolar lavage fluid. The protective effect of physical exercise on the alterations caused by lung injury, including lung edema was also evaluated. Wistar rats were submitted to 2 months of physical exercise. After this period the lung injury was induced by intratracheal instillation of lipopolysaccharide. Adult Wistar rats were submitted to 2 months of physical exercise and after this period the lung injury was induced by intratracheal instillation of lipopolysaccharide in dose 100 μg/100 g body weight. The sham group received isotonic saline instillation. Twelve hours after the injury was performed the respiratory mechanical and after the rats were decapitated and samples were collected. The rats subjected to lung injury presented a decrease in activities of the enzymes of the electron transport chain and ATP levels in lung, as well as the formation of pulmonary edema. A decreased lung dynamic and static compliance, as well as an increase in respiratory system resistance, and a decrease in phospholipids content were observed. Physical exercise was able to totally prevent the decrease in succinate dehydrogenase and complex II activities and the formation of pulmonary edema. It also partially prevented the increase in respiratory system resistance, but did not prevent the decrease in dynamic and static compliance, as well as in phospholipids content. These findings suggest that the mitochondrial dysfunction may be one of the important contributors to lung damage and that physical exercise may be beneficial in this pathology, although it did not prevent all changes present in lung injury.     

Therapeutic Effect of Intravenous Infusion of Perfluorocarbon Emulsion on LPS-Induced Acute Lung Injury in Rats

Acute lung injury (ALI) and its more severe form, acute respiratory distress syndrome (ARDS) are the leading causes of death in critical care. Despite extensive efforts in research and clinical medicine, mortality remains high in these diseases. Perfluorocarbon (PFC), a chemical compound known as liquid ventilation medium, is capable of dissolving large amounts of physiologically important gases (mainly oxygen and carbon dioxide). In this study we aimed to investigate the effect of intravenous infusion of PFC emulsion on lipopolysaccharide (LPS) induced ALI in rats and elucidate its mechanism of action. Forty two Wistar rats were randomly divided into three groups: 6 rats were treated with saline solution by intratracheal instillation (control group), 18 rats were treated with LPS by intratracheal instillation (LPS group) and the other 18 rats received PFC through femoral vein prior to LPS instillation (LPS+PFC group). The rats in the control group were sacrificed 6 hours later after saline instillation. At 2, 4 and 6 hours of exposure to LPS, 6 rats in the LPS group and 6 rats in LPS+PFC group were sacrificed at each time point. By analyzing pulmonary pathology, partial pressure of oxygen in the blood (PaO2) and lung wet-dry weight ratio (W/D) of each rat, we found that intravenous infusion of PFC significantly alleviated acute lung injury induced by LPS. Moreover, we showed that the expression of pulmonary myeloperoxidase (MPO), intercellular adhesion molecule-1 (ICAM-1) of endothelial cells and CD11b of polymorphonuclear neutrophils (PMN) induced by LPS were significantly decreased by PFC treatment in vivo. Our results indicate that intravenous infusion of PFC inhibits the infiltration of PMNs into lung tissue, which has been shown as the core pathogenesis of ALI/ARDS. Thus, our study provides a theoretical foundation for using intravenous infusion of PFC to prevent and treat ALI/ARDS in clinical practice.     

L-Arg对LPS诱导的急性肺损伤大鼠肺表面活性物质和肺泡巨噬细胞功能的影响

目的:探讨L-精氨酸(L-Arg)对脂多糖(LPS)诱导的急性肺损伤大鼠肺表面活性物质和肺泡巨噬细胞功能的影响。方法:舌下静脉注射脂多糖(LPS)复制肺损伤模型。健康雄性SD大鼠48只,随机分为对照组、模型组(LPS组)和L-Arg治疗组(L-Arg组)(n=16)。分别于给予LPS 3 h或6 h后给予生理盐水(对照组及LPS组,ip)和L-Arg(500 mg/kg ip)(L-Arg治疗组),治疗3 h。原位杂交法(ISH)检测肺组织中肺表面活性蛋白A(SP-A)mRNA的表达;测定肺泡灌洗液(BALF)中的总蛋白(TP)。体外分离培养大鼠肺泡巨噬细胞,以LPS(终浓度10 mg/L)处理巨噬细胞,观察L-Arg对肺泡巨噬细胞的影响。结果:与对照组比较,大鼠肺损伤后SP-A mRNA表达减弱,BALF中TP增多(P<0.01)。肺损伤3 h用L-Arg治疗3 h后,SP-A mRNA阳性细胞表达明显增强,BALF中TP较LPS组相同时间点明显降低(P<0.05,P<0.01),肺损伤减轻。体外实验中,与正常对照组相比,LPS组细胞培养上清中乳酸脱氢酶(LDH)、一氧化氮(NO)、肿瘤坏死因子-α(TNFα-)和白细胞介素-6(IL-6)浓度明显增高(P<0.01);L-Arg明显减少LPS所致的LDH的释放,降低TNFα-和IL-6浓度。结论:L-Arg可减轻内毒素性肺损伤,此机制可能与增强SP-AmRNA表达有关;LPS可刺激巨噬细胞分泌促炎因子和NO,L-Arg可抑制LPS对巨噬细胞的作用。     

Body temperature control in sepsis-induced acute lung injury

Body temperature is precisely regulated to maintain homeostasis in homeothermic animals. Although it remains unproved whether change of body temperature constitutes a beneficial or a detrimental component of the septic response, temperature control should be an important entity in septic experiments. We investigated the effect of body temperature control on the lipopolysaccharide (LPS)-induced lung injury. Acute lung injury in rats was induced by intratracheal spray of LPS and body temperature was either clamped at 37 degrees C for 5 hours or not controlled. The severity of lung injury was evaluated at the end of the experiment. Intratracheal administration of aerosolized LPS caused a persistent decline in body temperature and a significant lung injury as indicated by an elevation of protein-concentration and LDH activity in the bronchoalveolar lavage (BAL) fluid and wet/dry weight (W/D) ratio of lungs. Administration of LPS also caused neutrophil sequestration and lipid peroxidation in the lung tissue as indicated by increase in myeloperoxidase (MPO) activity and malondialdehyde (MDA) production, respectively. Control of body temperature at 37 degrees C after LPS (LPS/BT37, n = 11) significantly reduced acute lung injury as evidenced by decreases in BAL fluid protein concentration (983 +/- 189 vs. 1403 +/- 155 mg/L) and LDH activity (56 +/- 10 vs. 123 +/- 17 deltamAbs/min) compared with the LPS group (n = 11). Although the W/D ratio of lung and MDA level were lower in the rats received temperature control compared with those received LPS only, the differences were not statistically significant. Our results demonstrated that intratracheal administration of aerosolized LPS induced a hypothermic response and acute lung injury in rats and controlling body temperature at a normal range may alleviate the LPS-induced lung injury.