Surfactant degradation activity in bronchoalveolar lavage fluid from guinea pigs challenged with antigen

BACKGROUND AND OBJECTIVE: Surfactant dysfunction is a characteristic of bronchial asthma, but mechanisms of dysfunction following antigen exposure are not understood. The aim of this study was to examine whether bronchoalveolar lavage fluid (BALF) has surfactant degradation activity after antigen challenge, using an animal model of asthma. METHODS: BALF was collected 24 h after a challenge with aerosolized antigen solution in actively sensitized guinea pigs and from non-sensitized control guinea pigs. The surface tension of BALF was measured by pulsating bubble surfactometer. Surfactant activity was expressed as the minimum surface tension of BALF after 5 min of pulsation. BALF was separated into a cellular phospholipid fraction and supernatant, and reconstituted into 'pellet + supernatant' and 'pellet + saline' fractions. RESULTS: Surfactant activity of BALF from sensitized antigen-challenged animals was reduced after 4 h of incubation at 37 degrees C but a decrease was not observed in BALF from non-sensitized control animals. The decrease of surfactant activity in BALF from challenged animals was prevented by incubation at 4 degrees C. Disappearance of surfactant activity after incubation at 37 degrees C was observed in the 'pellet + supernatant', but not in the 'pellet + saline' fraction. The decrease of surfactant activity in BALF was also partially suppressed by the secretory phospholipase A2 inhibitor, indoxam, and by a cocktail of protease inhibitors. CONCLUSION: Surfactant-degrading activity was present in the supernatant of BALF from antigen-challenged guinea pigs. This activity may be attributed to secretory phospholipase A2 and to proteases present in the antigen-challenged airway.     

Airway hyperresponsiveness to cigarette smoke in ovalbumin-sensitized guinea pigs

This study was carried out to determine if the bronchoconstrictive effect of cigarette smoke (CS) is enhanced when airway hyperresponsiveness is induced by ovalbumin (Ova) sensitization, and if so, whether an increase in endogenously released tachykinins is involved. The bronchoconstrictive effects of an acute CS inhalation challenge (15 ml; 50% concentration) were compared between guinea pigs sensitized with aerosolized Ova and matching control animals (receiving saline aerosol). In Ova-sensitized animals, there were marked increases in the numbers of eosinophils and neutrophils in the bronchoalveolar lavage fluid (BALF), which was accompanied by an elevated bronchomotor response to acetylcholine (ACh). The baseline lung resistance (RL) and dynamic pulmonary compliance (Cdyn) were not significantly different between the two groups; however, the same CS inhalation challenge evoked a significantly more intense bronchoconstriction in the Ova-sensitized group (control group: DeltaRL = 68 +/- 8%, DeltaCdyn = -26 +/- 6%; Ova group: DeltaRL = 425 +/- 76%; DeltaCdyn = -47 +/- 8%). The levels of substance P-like immunoreactivity (SP-LI) and calcitonin gene-related peptide-like immunoreactivity (CGRP-LI) measured in the bronchoalveolar lavage (BAL) collected after CS inhalation challenge were also significantly greater in Ova-sensitized animals than in control animals. Furthermore, pretreatment with SR-48968, a selective antagonist of neurokinin-2 (NK(2)) receptor, inhibited more than 85% of the enhanced bronchomotor responses to CS challenge, but did not significantly reduce the airway hyperresponsiveness to ACh in Ova-sensitized guinea pigs. These results show that Ova sensitization induces airway hyperresponsiveness to inhaled CS, and that the endogenous tachykinins evoked by CS-induced activation of lung C fibers play a primary role in this augmented response.     

Early and late-phase bronchoconstriction after allergen challenge of nonanesthetized guinea pigs. I. The association of disordered airway physiology to leukocyte infiltration

We describe a guinea pig model of asthma in which animals were sensitized and challenged by inhalation of aerosolized ovalbumin. Challenge was performed under cover of mepyramine (10 mg/kg) to allow a high enough concentration of ovalbumin to elicit consistent late responses. Airway resistance and thoracic gas volume of conscious guinea pigs was assessed by whole body plethysmography before and at regular intervals for as long as 72 h after challenge. At the same time points, cellular changes in the lung were assessed by both examination of cells recovered by bronchoalveolar lavage (BAL) and lung histology. There were no significant changes in specific airway conductance (SGaw), BAL cell content or lung histology in animals challenged with saline control. Challenge with 2% ovalbumin caused an early fall in SGaw, which peaked at 2 h and amounted to a 43.7 +/- 4.1% fall from baseline. This was followed by 2 late responses, the first reaching maximum at 17 h with a 46.9 +/- 4.5% decrease in SGaw from baseline and the second at 72 h with a 39.0 +/- 3.5% fall in SGaw. Examination of BAL fluid revealed a 7-fold increase in neutrophils at 6 h and a 17-fold increase at 17 h, after which numbers decreased to baseline. Eosinophilia developed more slowly, being insignificant at 6 h and 6-fold at 17 h; by 72 h, eosinophils constituted 48.9 +/- 6.9% of the total cells recovered. No changes in mononuclear cells or lymphocytes were observed. Histologic examination of the lung revealed a progressive eosinophil infiltration of the airways, but not alveoli or vascular bed. Electron microscopy showed degranulation of eosinophils recovered by BAL and discharge of mucus from goblet cells in the trachea. Because these changes are similar to those that occur after allergen challenge in human asthma, we suggest that this represents a useful animal model in which to study the mechanism of early and late bronchoconstriction responses.     

Antiinflammatory effects of genistein,a tyrosine kinase inhibitor,on a guinea pig model of asthma

Protein tyrosine kinase signaling cascade plays a pivotal role in the activation of inflammatory cells. The purpose of this study was to investigate the effects of genistein, a broad-spectrum protein tyrosine kinase inhibitor, on airway inflammation in an in vivo guinea pig model of asthma. Guinea pigs were actively sensitized by intraperitoneal injections of ovalbumin. Aerosolized ovalbumin induced acute bronchoconstriction in conscious animals in a dose-dependent manner. Genistein (15 mg/kg given intraperitoneally) markedly inhibited ovalbumin-induced, but not histamine- and methacholine-induced, acute bronchoconstriction. In addition, genistein significantly reduced ovalbumin-induced increases in total cell counts and eosinophils recovered in bronchoalveolar lavage fluid, airway eosinophilia, and eosinophil peroxidase activity in cell-free bronchoalveolar lavage fluid and markedly attenuated ovalbumin-induced airway hyperresponsiveness to inhaled methacholine. Immunoblot analysis of lung lysates isolated from genistein-pretreated animals showed that epidermal growth factor-induced tyrosine phosphorylation in lung tissues was inhibited by genistein. These results implicate that inhibition of tyrosine kinase signaling cascade may have therapeutic potential for allergic airway inflammation.     

The effect of natural adjuvants on tracheal responsiveness and cell count in lung lavage of sensitized guinea pigs

Background and objective:   Airway inflammation is a well-characterized pathological feature of asthma. The effects of two natural adjuvants on lungs of sensitized guinea pigs were examined.
Methods:   The responses of guinea pig tracheal chains, WBC, differential WBC in lung lavage and IL-4 and interferon (IFN)-γ levels in serum were examined in control guinea pigs and four treatment groups, including sensitized animals (S) and sensitized animals treated with the adjuvants PC (S + PC), G2 (S + G2) or both adjuvants (S + PCG2) ( n  = 6). Animals were sensitized by injection and inhalation of ovalbumin.
Results:   Tracheal responsiveness to methacholine (concentration of methacholine causing 50% of maximum contraction), WBC, eosinophil, neutrophil and basophil numbers were increased and lymphocyte numbers were decreased in lung lavage of sensitized animals compared with the control group ( P  < 0.01 to P  < 0.001). However, G2 adjuvant and the combination of G2 and PC adjuvants caused a significant reduction in tracheal responsiveness ( P  < 0.01 and P  < 0.001, respectively). In addition both adjuvants prevented changes in WBC ( P  < 0.001 for both). Both adjuvants and the combination prevented changes in eosinophil, neutrophil and basophil numbers in lung lavage of sensitized animals ( P  < 0.05 to P  < 0.001). The adjuvants also prevented changes in IL-4 but increased IFN-γ levels in all treatment groups compared with group S ( P  < 0.001 for all cases).
Conclusions:   These results indicate that the two natural adjuvants (especially G2 adjuvant) and their combination have therapeutic effects, with reduction in tracheal responsiveness and WBC in lung lavage of sensitized guinea pigs.     

Surfactant phospholipids and lavage phospholipase A2 in experimental Pneumocystis carinii pneumonia

The effect of Pneumocystis carinii pneumonia on surfactant phospholipids and lavage phospholipase A2 was investigated. Pneumocystis carinii infection was induced in adult rats by immunosuppression with dexamethasone administered in the drinking water (2 mg/L) for 6 to 8 wk. Surfactant phospholipids were isolated from lung lavage and lung tissue. Dexamethasone administration significantly increased total lung and lavage phospholipids in corticosteroid-treated animals receiving prophylaxis against P. carinii with trimethoprim-sulfamethoxazole (TMP-SMZ) when compared with no treatment control animals. Lavage surfactant phospholipids from P. carinii-infected rats were 25% that of no treatment control rats and less than 10% that of corticosteroid control animals receiving TMP-SMZ. Phospholipid composition of lavage phospholipids was also altered in P. carinii pneumonia, with slight increase in the percentage of sphingomyelin and reduced percentage of total phosphatidylcholine. Postlavage tissue phospholipids of P. carinii-infected rats were 4 times that of no treatment control animals, although only about 50% that of corticosteroid control animals. There was no significant difference in lavage phospholipase A2 activity for the P. carinii-infected and corticosteroid control groups, although the enzyme activity was at least 4 times that of the no treatment control group. The surfactant changes were associated with abnormal excised lung pressure-volume curves and decreased deflation stability in the animals with P. carinii. These results indicate that the corticosteroids used in this model induce an increase in both lung surfactant phospholipids and phospholipase A2. Despite this increase in lavage phospholipids, P. carinii pneumonia in this model causes an alveolar surfactant phospholipid deficiency without significant increase in phospholipase A2 activity.(ABSTRACT TRUNCATED AT 250 WORDS)     

Anaphylactic challenge causes eosinophil accumulation in bronchoalveolar lavage fluid of guinea pigs. Modulation by betamethasone, phenidone, indomethacin, WEB 2086, and a novel antiallergy agent, SCH 37224

Eosinophil infiltration into bronchoalveolar areas of the lung has been assessed in guinea pigs sensitized to ovalbumin (OA) and then challenged with the aerosolized antigen. Cell content, histamine, and guinea pig albumin (GPA) have been measured in bronchoalveolar lavage (BAL) fluid from these animals. Extensive eosinophil accumulation resulted from sensitization followed by OA challenge; monocytes that initially accounted for greater than 80% of the BAL cells remained essentially constant, and neutrophils comprised less than 3% of the population throughout. Eosinophils were elevated at 3 h, peaked with a fivefold increase at 24 h, and remained elevated for at least 7 days. Histopathologic changes observed in lungs taken from sensitized guinea pigs 24 h after OA challenge confirm this eosinophilia. Increased histamine and GPA were detected only at 5 min. Oral treatment with betamethasone (ED50 = 0.4 mg/kg), phenidone (ED50 = 15 mg/kg), Sch 37224 (ED50 = 0.5 mg/kg), and WEB 2086 (ED50 = 4 mg/kg) decreased eosinophil accumulation in the BAL fluid, indicating roles for 5-lipoxygenase products and PAF in this multimediator-dependent model of allergic inflammation. On the other hand, 4 mg/kg of indomethacin increased total cells with no effect on eosinophils, precluding a major role for cyclooxygenase products. Sch 37224, an antileukotriene agent and an orally active novel antiallergy agent in sheep, guinea pigs, and humans, is as potent as betamethasone at blocking eosinophil infiltration, suggesting that it may also suppress human pulmonary inflammation.     

缓激肽B2受体拮抗剂对致敏豚鼠模型咳嗽反应性的影响

目的研究缓激肽受体B2拮抗剂FR173657对卵蛋白致敏和激发豚鼠咳嗽反应性的影响.方法正常和卵蛋白致敏豚鼠各40只,卵蛋白雾化吸入激发.24 h后,再各自分成对照组、小剂量FR173657组、中剂量FR173657组和大剂量FR173657组.每组10只,分别腹腔注射生理盐水、FR173657溶液0.03 mg/kg、0.3 mg/kg和3 mg/kg,观察吸入辣椒素溶液诱导的咳嗽反应.用非侵入性方法测量正常对照组、致敏对照组和致敏中剂量FR173657组豚鼠的特异性气道阻力.结果不同剂量的FR173657不影响正常豚鼠的咳嗽反应和气道阻力.致敏对照组豚鼠吸入10-4 mol/L辣椒素溶液诱导的咳嗽次数和特异性气道阻力分别为[(21.7±3.0)次/3 min]和[(9.4±0.5) cm H2O/s]与正常对照组[(8.3±1.4)次/3 min,(7.9±0.9) cm H2O/s] 比较,差异有显著性(P<0.05),中剂量FR173657能抑制这些改变,咳嗽次数和特异性气道阻力分别为[(12.2±1.3)次/3 min,(7.5±0.9) cm H2O/s],两组比较差异有显著性(P<0.05).结论缓激肽B2受体拮抗剂抑制致敏豚鼠卵蛋白激发后增高的咳嗽反应和气道阻力.因此,缓激肽可能是嗜酸细胞性气道炎症所致咳嗽的重要介质.     

哮喘豚鼠肺组织中嗜酸细胞凋亡与白细胞介素5mRNA表达？…

目的 探讨哮喘时嗜酸细胞（ＥＯＳ）凋亡与肺组织白细胞介素５（ＩＬ－５）ｍＲＮＡ表达的关系。方法 将豚鼠随机分为对照组（正常组７只）、哮喘组（８只）、地塞米松组（８只），应用脱氧核糖核酸末端转移酶介导的缺口末端标记（ＴＵＮＥＬ）技术和原位杂交方法，检测支气管肺泡灌洗液（ＢＡＬＦ）中不同密度ＥＯＳ凋亡百分比和肺组织ＩＬ－５ｍＲＮＡ的表达。结果 （１）正常对照组ＢＡＬＦ中低密度ＥＯＳ、正常密度ＥＯＳ凋是     

Effect of TRFK-5 on Airway Responsiveness in Ovalbumin-Treated Guinea Pigs Exposed to Tobacco Smoke

Tobacco smoke (TS) exposure can induce airway hyperresponsiveness, especially in asthma. A feature of asthma is eosinophilia. We hypothesized that tobacco smoke exposure enhances eosinophil responsiveness in sensitized guinea pigs. Tobacco smoke-exposed, ovalbumin (OA)-sensitized guinea pigs were treated with TRFK-5 (1.0 mg/kg, intraperitoneal), an anti-interleukin (IL)-5 agent, or its vehicle. Guinea pigs were challenged with aerosols of OA, capsaicin, histamine, and methacholine. TRFK-5 attenuated airway responsiveness to OA but not to capsaicin, histamine, or methacholine. Bronchial alveolar lavage fluid analysis confirmed TRFK-5 attenuated airway eosinophilia in OA-treated guinea pigs. Therefore, airway responsiveness to OA is enhanced by eosinophils or IL-5 itself.     

Effect of TRFK-5 on airway responsiveness in ovalbumin-treated guinea pigs exposed to tobacco smoke.

Tobacco smoke (TS) exposure can induce airway hyperresponsiveness, especially in asthma. A feature of asthma is eosinophilia. We hypothesized that tobacco smoke exposure enhances eosinophil responsiveness in sensitized guinea pigs. Tobacco smoke-exposed, ovalbumin (OA)-sensitized guinea pigs were treated with TRFK-5 (1.0 mg/kg, intraperitoneal), an anti-interleukin (IL)-5 agent, or its vehicle. Guinea pigs were challenged with aerosols of OA, capsaicin, histamine, and methacholine. TRFK-5 attenuated airway responsiveness to OA but not to capsaicin, histamine, or methacholine. Bronchial alveolar lavage fluid analysis confirmed TRFK-5 attenuated airway eosinophilia in OA-treated guinea pigs. Therefore, airway responsiveness to OA is enhanced by eosinophils or IL-5 itself.     

Idiopathic pulmonary fibrosis. Abnormalities in bronchoalveolar lavage fluid phospholipids

Bronchoalveolar lavage has been used to sample cells and proteins in the distal lung. One of the major secretory products of the alveolar type II epithelial cells, pulmonary surfactant, can be recovered by lavage. Abnormalities in alveolar type II cells are found in biopsies of patients with idiopathic pulmonary fibrosis (IPF), and abnormalities of pulmonary surfactant phospholipids have been reported after diffuse lung injury in animals and in humans. Therefore, we questioned if abnormalities in lavage phospholipids might also occur in IPF, a chronic inflammatory disease of the alveolar epithelium and interstitium, and, if present, would these abnormalities reflect histopathologic changes or predict responsiveness to therapy. Fifteen untreated patients with IPF, diagnosed by open lung biopsy, were studied and were found to have less than half the amount of bronchoalveolar lavage phospholipid as that recovered from healthy volunteers (p less than 0.05). In addition, patients with IPF had a lower proportion of phosphatidylglycerol and a higher proportion of phosphatidylinositol in the recovered phospholipids than did healthy volunteers (p less than 0.05). The severity of these alterations in phospholipid composition correlated with more advanced fibrotic histopathologic changes. Patients with less depression of total phospholipids in lavage improved with corticosteroid therapy, whereas the patients with more severely decreased total phospholipid recovered in lavage did not.     

Aerosolized Polymerized Type I Collagen Reduces Airway Inflammation and Remodelling in a Guinea Pig Model of Allergic Asthma

Collagen-polyvinylpyrrolidone (Collagen-PVP) has been demonstrated to elicit immunomodulatory properties in different chronic inflammatory diseases. Nevertheless, its effects on asthma are still unknown. We have evaluated whether collagen-PVP could modulate airway inflammation and remodelling in a guinea pig model of allergic asthma. Sensitized guinea pigs were challenged with the allergen (ovalbumin) six times (at 10-day intervals). From the third challenge on, animals were treated every 5 days with saline aerosols containing 0.16, 0.33, or 0.66 mg/ml of collagen-PVP (n = 5, respectively). Some guinea pigs, sensitized and challenged with saline as well as treated with 0 or 0.66 mg/ml collagen-PVP, were included in the study as control (n = 7) and sham groups (n = 5), respectively. From the first challenge on, ovalbumin induced a transient airway obstruction, measured by barometric plethysmography, which was not modified by collagen-PVP treatments. After the last allergen challenge, guinea pigs were anesthetized to obtain bronchoalveolar lavage (BAL) and the left lung caudal lobe. As expected, BAL cell count from allergen-challenged guinea pigs showed abundant neutrophils and eosinophils, as well as numerous tumor necrosis factor (TNF)-α-expressing granulocytes and macrophages in airway wall (determined by immunohistochemical assay). Neutrophilia and TNF-α-expressing leukocytes, from collagen-PVP treated animals, diminished from 0.16 mg/ml, and eosinophilia from 0.66 mg/ml of collagen-PVP doses. Histological changes induced by allergen challenges include thickening of connective tissue below airway epithelium and vascular wall widening of airway adjacent vessels; these changes were reduced by collagen-PVP treatment. Collagen-PVP seems to have anti-inflammatory and antifibrotic properties in this guinea pig asthma model.     

Inflammatory mediators and cellular infiltration of the lungs in a guinea pig model of the late asthmatic reaction

Alterations in cell numbers, vascular permeability, and concentrations of various inflammatory mediators in the lung were measured in a guinea pig model of the late asthmatic reaction. Animals sensitized by inhalation of ovalbumin were challenged with an aerosol of ovalbumin or saline, and bronchoalveolar lavage fluid (BALF) and peripheral blood were collected after periods ranging from 5 min to 72 h. Increased vascular leakage within the lungs was indicated by elevated BALF/plasma albumin ratios at all time points, and was maximal 6 h after challenge. There were increased numbers of eosinophils in BALF by 6 h after challenge and they remained elevated at least until 72 h. A corresponding increase in the proportion of blood leukocytes represented by eosinophils was observed at 6 and 17 h, which suggests that these cells may be drawn to the lung following their release into the circulation, but by 72 h the proportion in blood had returned to normal. A transitory neutrophilia was evident in BALF and blood 6 h after allergen exposure, but there were no allergen-induced changes in BALF numbers of macrophages, lymphocytes, epithelial cells, or mast cells (as assessed by concentrations of cell-associated histamine). beta-Glucuronidase activity was significantly increased in BALF of guinea pigs at 2 h and 17 h following challenge. The degree to which eicosanoids can be recovered in BALF was investigated by instilling a range of tritiated compounds into the lungs of normal guinea pigs at the time of lavage. Ratio high-performance liquid chromatography revealed that there had been little metabolism of the eicosanoids recovered in BALF. However, there was evidence for a rapid removal of these mediators from the lung, a process which will militate against their accurate quantitation in BALF. Histamine, prostaglandin D2, and thromboxane B2 were detected in BALF but did not differ between treatment groups, and levels showed no simple relationship with the other inflammatory changes measured.     

Inflammatory mediators and cellular infiltration of the lungs in a guinea pig model of the late asthmatic reaction

Alterations in cell numbers, vascular permeability, and concentrations of various inflammatory mediators in the lung were measured in a guinea pig model of the late asthmatic reaction. Animals sensitized by inhalation of ovalbumin were challenged with an aerosol of ovalbumin or saline, and bronchoalveolar lavage fluid (BALF) and peripheral blood were collected after periods ranging from 5 min to 72 h. Increased vascular leakage within the lungs was indicated by elevated BALF/plasma albumin ratios at all time points, and was maximal 6 h after challenge. There were increased numbers of eosinophils in BALF by 6 h after challenge and they remained elevated at least until 72 h. A corresponding increase in the proportion of blood leukocytes represented by eosinophils was observed at 6 and 17 h, which suggests that these cells may be drawn to the lung following their release into the circulation, but by 72 h the proportion in blood had returned to normal. A transitory neutrophilia was evident in BALF and blood 6 h after allergen exposure, but there were no allergen-induced changes in BALF numbers of macrophages, lymphocytes, epithelial cells, or mast cells (as assessed by concentrations of cell-associated histamine).β-Glucuronidase activity was significantly increased in BALF of guinea pigs at 2 h and 17 h following challenge. The degree to which eicosanoids can be recovered in BALF was investigated by instilling a range of tritiated compounds into the lungs of normal guinea pigs at the time of lavage. Ratio high-performance liquid chromatography revealed that there had been little metabolism of the eicosanoids recovered in BALF. However, there was evidence for a rapid removal of these mediators from the lung, a process which will militate against their accurate quantitation in BALF. Histamine, prostaglandin D₂, and thromboxane B₂ were detected in BALF but did not differ between treatment groups, and levels showed no simple relationship with the other inflammatory changes measured.     

Effect of whole-body x-irradiation on antigen-induced airway response in sensitized guinea pigs.

The objectives of this study were to test the hypothesis that x-irradiation inhibits the late asthmatic response (LAR) without influencing the early asthmatic response (EAR) and to examine the mechanism of the inhibitory effect. Twenty sensitized guinea pigs were irradiated at a dose of 8 Gy. The next day, one-half of the animals were injected intravenously with spleen cells (2 x 10(8)) collected from unirradiated sensitized guinea pigs, whilst the other half were injected with vehicle only. Ten additional unirradiated sensitized guinea pigs also received vehicle only. Antigen inhalation challenge took place two days later. Pulmonary resistance was measured for 6 h after antigen exposure, and bronchoalveolar lavage and lung fixation were then undertaken. The area under the percentage pulmonary resistance curve 2-6 h after allergen inhalation was used for analysis of the LAR, while the maximal percentage change in pulmonary resistance was used for analysis of the EAR. Irradiation abolished the LAR (364.4+/-49.4 versus 62.8+/-10.4) without inhibiting the EAR (229.3+/-27.2 versus 278.7+/-40.2) and significantly inhibited the accumulation of eosinophils and lymphocytes in the airways. Transfer of spleen cells restored the LAR (334.4+/-66.8) and the recruitment of cells to the levels seen in unirradiated sensitized guinea pigs. In addition, transfer of only CD4+ T-lymphocytes separated from the spleen cells restored the LAR (439.4+/-62.1) and the cell infiltration into the airways. These inhibitory effects of x-irradiation were due to decreases in numbers of CD4+ T-lymphocytes.     

Effect of aluminum inhalation on alveolar phospholipid profiles in experimental silicosis

In the sheep tracheal lobe model of silicosis, we have recently reported that total phospholipid, lecithin, and phosphatidylglycerol levels were elevated in lung lavage. To investigate further this observation, we obtained complete phospholipid profiles of lung lavage in 10 sheep exposed to saline only (Sa group), 10 sheep exposed to aluminum lactate inhalation only (Al group), 10 sheep exposed to 100 mg Minusil-5 in saline followed by monthly saline inhalation (Si group), and 10 sheep exposed to 100 mg Minusil-5 in saline followed by monthly aluminum lactate inhalation (Si-Al group). The following phospholipid components were measured: total phospholipids, phosphatidylglycerol (PG), phosphatidylethanolamine (PE), phosphatidylinositol (PI), phosphatidylcholine, disaturated phosphatidylcholine, sphingomyelin, and lyso-phosphatidylcholine. All values were comparable in the Sa group, Al group, and Si-Al group. In the Si group, there was a significant increase in total phospholipid to approximately 200% of the control values. The phospholipid profile of this group demonstrated an increase in all of the phospholipid components with some enrichment of the fraction of PG, PE, and PI. We concluded that lung exposure to silica dust significantly increases the concentration of phospholipids in the alveoli. This increase is of a large spectrum of alveolar phospholipids and is completely suppressed by aluminum lactate inhalation.     

Bronchoalveolar lavage and histologic characterization of late asthmatic response in guinea pigs

To elucidate the mechanisms of late asthmatic response (LAR) observed in asthmatic subjects, we have developed an animal model of LAR using guinea pigs. Fifty guinea pigs were immunized with a mixture of Ascaris suum extract and aluminum hydroxide and then challenged with an inhalation of Ascaris suum extract without anesthesia. Twenty of the 50 guinea pigs showed a dual asthmatic response in which the LAR occurred 3 to 6 h after immediate asthmatic response (IAR). Histologic studies by rapid freezing with liquid nitrogen or bronchoalveolar lavage (BAL) were performed in 14 of these 20 guinea pigs with LAR and compared with those in 10 of 18 guinea pigs with only IAR, 10 control guinea pigs, and 10 nonimmunized but challenged guinea pigs. Both the percentage and the absolute number of neutrophils in the BAL fluid of the guinea pigs with LAR were significantly greater than those of the control guinea pigs (p less than 0.02) and than those of the nonimmunized but challenged guinea pigs (p less than 0.02). However, that of guinea pigs with LAR was not significantly different from that of guinea pigs with only IAR. On the other hand, histologic examination showed that eosinophil infiltration within the airway walls of the guinea pigs with LAR was more prominent than that of the guinea pigs with only IAR, and showed that there was no significant difference in neutrophil infiltration within the airway walls between the guinea pigs with LAR and the animals with only IAR. Contraction of airway (bronchus, bronchiole) smooth muscle, submucosal edema, and mucus in airway lumen were also observed in LAR.(ABSTRACT TRUNCATED AT 250 WORDS)     

人副流感病毒三型感染对豚鼠咳嗽敏感性的影响

目的 研究人副流感病毒3型(PIV3)感染对豚鼠咳嗽敏感性(CRS)的影响.方法 将雄性SPF级豚鼠60只按随机数字表法分成对照组、感染6 d组、感染12 d组、感染28 d组、感染42 d组和哮喘组,每组10只.病毒株为PIV3,经体外细胞培养扩增后,通过滴鼻方法接种于感染组豚鼠呼吸道;对照组接种细胞培养基;哮喘组给予卵清白蛋白致敏及诱发哮喘.辣椒素刺激后用BUXCO肺功能仪测定各组豚鼠CRS,同时测定气道高反应性(AHR),并行BALF细胞学检测及肺组织病理学观察.结果感染后6、12、28和42 d组豚鼠CRS[中位数(四分位数间距)]分别为7.50(5.25)、7.30(7.25)、8.40(9.75)和8.20(5.50)CCnt(咳嗽总次数),均高于对照组的2.50(3.00)CCnt(均P<0.05),感染后42 d组升高最明显;哮喘组CRS为3.90(1.75)CCnt,与对照组比较差异无统计学意义(P=0.18).感染后6 d组豚鼠AHR明显;感染组豚鼠BALF中炎症细胞总数均较对照组明显升高,感染6 d和12 d组淋巴细胞明显升高.病理学检查显示感染组豚鼠急性期气道炎症表现为主,未见明显的肺实质炎症.结论 PIV3感染导致豚鼠CRS在急性和亚急性咳嗽期动态增高,CRS升高可能是豚鼠病毒感染引起咳嗽的关键特征.     

Suplatast tosilate inhibits late response and airway inflammation in sensitized guinea pigs.

The effect of suplatast tosilate, which has been proven to inhibit T-cell synthesis of IL-4 and IL-5, on the response to antigen inhalation challenge was investigated in sensitized guinea pigs. The animals were given an oral dose of 30 or 100 mg/kg of suplatast or vehicle (distilled water) daily for 1 wk before antigen challenge. Measurement of pulmonary resistance for 6 h was followed by bronchoalveolar lavage and lung fixation. After antigen challenge, all guinea pigs in the vehicle group displayed dual-phase airway obstruction and accumulation of eosinophils and lymphocytes in the airways. After 1 wk of treatment with the high dose of suplatast, the late asthmatic response and the recruitment of eosinophils and lymphocytes into the airways were significantly inhibited, but the early asthmatic response was not affected. In situ hybridization revealed that challenge-induced increases in IL-5 mRNA-positive cells in lung tissue were significantly inhibited after treatment. Thus, suplatast inhibited airway obstruction in the late phase by specifically inhibiting the inflammatory process after mast cell degranulation.