• The Korean Journal of Physiology
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• v.29 no.2
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• pp.251-257
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• 1995

The objective of the present study was to test the effect of platelet-activating factor (PAF) on rat alveolar macrophages. PAF alone did not stimulate superoxide secretion from alveolar macrophages. However, PAF $(10^{-5}\;M)$ significantly enhanced phagocytic activator zymosan-induced superoxide secretion from alveolar macrophages. This enhancement of PAF plus zymosan was 30% above the sum of the separate effects of PAF and zymosan. Similarly, PAF $1.3{\times}(10^{-5}\;M)$ was not a direct stimulant of alveolar macrophages, as it had no stimulatory effect on chemiluminescence generation, but potentiated zymosan-induced activation of chemiluminescence, i.e., 162% above the separate effects of each stimulant. PAF $10^{-16}{\pm}10^{-6}\;M$ also failed to stimulate IL-1 production from alveolar macrophages. In contrast, when both PAF $10^{-10}\;M$ and lipopolysaccharide(LPS) $(1 {\mu}g/ml)$ were added together at the initiation of the culture, IL-1 production was significantly increased indicating the potentiative effects of PAF on IL-1 production by alveolar macrophages. Collectively, these data suggest that PAF alone does not activate the release of bioactive products from alveolar macrophages. However, PAF appears to act as a priming mediator that potentiates stimuli-induced macrophage activity. These novel actions of PAF prove its role as a potent mediator of inflammatory and immune responses in the lung.

• Tuberculosis and Respiratory Diseases
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• v.41 no.5
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• pp.513-520
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• 1994

Background: The pathogenesis of silicosis has been focused on the interaction between alveolar macrophages and silica particle. Although fibrosis in silicosis has been studied extensively, the mechanism is still not fully understood. There is increasing evidence that monokines and arachidonic acid metabolites macrophage are involved in pathogenesis of silicosis. Recently, it was reported that prostaglandin E2 produced from macrophage counteracts the stimulatory effects of other monokines on fibroblast proliferation or collagen production. Until now, it was remained uncertain by which mechanism silica particle may activate alveolar macrophage to an enhanced release of prostaglandin E2. Methods: In order to investigate the relationship between the activity of alveolar macrophage and the production of $PGE_2$ from activated alveolar macrophage, the authors measured hydrogen peroxide and $PGE_2$ from alveolar macrophages activated by silica in vitro and from alveolar macrophages in the silicotic nodules from rat. Experimental silicosis was induced by intratracheal infusion of silica($SiO_2$) suspended in saline(50 mg/ml) in Sprague-Dawley rats. Results: produced by 1) The silicotic nodules with fibrosis were seen from the sections of rat lung at 60 days after intratracheal injection with 50 mg aqueous suspension of silica(Fig. 1). 2) In vitro, silica caused the dose dependent increase of hydrogen peroxide(p<0.05, Fig. 2A) and $PGE_2$(p>0.05, Fig. 2B) release from alveolar macrophages. Alveolar macrophages from rat with silicotic nodules released more hydrogen peroxide and $PGE_2$ than those of control group(p<0.05, Fig. 3). Conclusion: These results suggest that silica particle could activate macrophage directly and enhanced the release of $PGE_2$ and hydrogen peroxide from the alveolar macrophage.

• Tuberculosis and Respiratory Diseases
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• v.48 no.4
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• pp.478-486
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• 2000

Background : In acute lung injury, alveolar macrophages play a pivotal role in the inflammatory process during the initiation phase and in the reconstruction and fibrosis process during the later phase. Recently, it has been proven that alveolar macrophages are constituted by morphologically, biochemically and immunologically heterogenous cell subpopulations. The possibility of alterations to these characteristics of the alveolar macrophage population during lung disease has been raised. To investigate such a possibility a hyperoxic rat lung model was made to check the distributional and morphological changes of rat alveolar macrophage subpopulation in acute hyperoxic lung injury. Method : Alveolar macrophage were lavaged from normal and hyperoxic lung injury rats and separated by discontinuous gradients of percoll. After cell counts of each density fraction were accessed, the morphomeric analysis of alveolar macrophages was performed on cytocentrifuged preparations by transmission electron micrograph. Result : 1. The total alveolar macrophage cell count significantly increased up to 24 hours after hyperoxic challenge (normal control group $171.6{\pm}24.1{\times}10^5$, 12 hour group $194.8{\pm}17.9{\times}10^5$, 24 hour group $207.6{\pm}27.1{\times}10^5$, p<0.05). oHoHH However the 48 hour group ($200.0{\pm}77.8{\times}10^5$) did not show a significant difference. 2. Alveolar septal thickness significantly increased up to 24 hours after hyperoxic challenge(normal control group $0.7{\pm}0.2{\mu}m$, 12 hour group $1.5{\pm}0.4{\mu}m$, 24 hour group $2.3{\pm}0.4{\mu}m$, p<0.05). However the 48 hour group did not show further change ($2.5{\pm}0.4{\mu}m$). Number of interstitial macrophage markedly increased at 24 hour group. 3. Hypodense fraction(fraction 1 and fraction 2) of alveolar macrophage showed a significant increase following hyperoxic challenge ($\beta=0.379$.$\beta=0.694$. p<0.05) ; however, fraction 3 was rather decreased following the hyperoxic challenge($\beta=0.815$. p<0.05), and fraction 4 showed an irregular pattern. 4. Electron microscopic observation of alveolar macrophage from each fraction revealed considerable morphologic heterogeneity. Cells of the most dense subfraction(fraction 4) were small, round, and typically highly ruffled with small membrane pseudopods. Cells of the least dense fraction (fraction 1) were large and showed irregular eccentric nucleus and high number of heterogenous inclusions. Conclusion : In conclusion, these results suggest that specific hypodense alveolar macrophage subpopulation may play a an important role in an acute hyperoxic lung injury model But further study, including biochemical and immunological function of these subpopulations, is needed.

• Toxicological Research
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• v.17 no.4
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• pp.255-265
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• 2001

Epidemiologic studies have demonstrated an association between short-term exposure to particulate air pollutants and increased mortality. However the biological mechanism underlying these associations have not been fully established and also the chemical and physical characteristics of the pollutant particles are not well understood. The metal constituents of air pollutant particles and their bioavailability are considered to Play an important role as possible mediators of Particle-induced airway injury and inflammation. Sprague-Dawley rat alveolar macrophage cells (NR8383) were exposed to airborne and acid-leached particulate matter (PM). Titanium oxide and nickel subsulfide were used as negative and positive controls. Particle-induced reactive oxygen species formation in cells was detected using the fluorescent probe 2',7'-dichlorofluorescin diacetate. Expression of TNF-$\alpha$ and IL-6 were measured by enzyme-linked immunosorbent assay, and PM-induced DNA double-strand breaks were determined with $\lambda$DNA/Hind III marker. Metals associated with air pollutant particles mediated intracellular oxidant production in alveolar macrophages, and the cytotoxicity and proinflammatory cytokine production induced by PM were associated with oxidative stress. The oxidants produced by air pollutant particles also are likely to induce DNA double-strand breaks. Our findings in alveolar macrophage cells exposed to PM and acid-leached PM support the hypothesis that metal components in urban air pollutants and their bioavailabilities might play an Important role in the induction of the adverse health effects.

• Archives of Pharmacal Research
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• v.18 no.4
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• pp.262-266
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• 1995

Bacterial lipopolysaccharide (LPS) is one of the most potent inducers of various cytokines nad other proinflammatory mediators in macrophages. Although pathophysiological consequences of LPS-induced responses are well established, the mechanisms through which LPS-generated singals are transduced remain unclear. In the present study, we attempted to determine early intracellular events after LPS binding which transduced the signal for the induction of arachidonic acid metabolism in rat alveolar macrophages. While H-7, a protein kinase C(PKC) inhibitor, did not affect LPS-stimulated prostaglandin synthesis, staurosporine enhanced archidonic acid etabolism in macropahages treated with LPS. Phorbol-12-myristate-13 acetate snesitive to LPS compare with control group. PMA and H-7 did not alter the effect of flucose. Pertussis toxin did not show nay effect, thus pertussis toxin snesitive G-protein pathway appears not to play a role in this experimental system. Genistein and tyrphostin 25, protein tyrosine kinase 9PTK) inhibitors, markedly inhibited prostaglandin synthesis in macrophages nal transduction events leading to icnreased macrophage arachidonic acid metabolism.

• Journal of Food Hygiene and Safety
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• v.8 no.4
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• pp.181-188
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• 1993

It is well known that bacterial lipopolysaccharide (LPS) stimulates the prostaglandin (PG) synthesis in various experimental system, but the mechanism and the detailed nature of its action are yet to be understood. Thus, this study was designed to characterize LPS induced PG synthesis in rat alveolar macrophage. Although results were not so much prominent, LPS stimulated PGE2 synthesis in macrophage with short term exposure, and this was thought to be mainly due to the activation of phopholipase A2+ But there was a burst in the PG synthesis 6 hours after the LPS treatment and this was accompanied with the increase of cyclooxygenase activity. This effect was not mediated by tumor necrosis factor (TNF) or platelet activating factor (PAF), and the existence of serum was prerequisite for its action. Growth factors such as epidermal growth factor (EGF) and platelet derived growth factor (PDGF) themselves did not stimulate PG synthesis and the showed stimulatory activities to some extent. Normal rat serum was more effective for the elicitation of the LPS action than growth factors. Thus, considering the amounts of growth fafctors contained in normal serum, it was suggested that another factors like LPS binding protein (LBP) might be involved in the serum effect on LPS action. Conclusively. it was thought that LPS could stimulate PG synthesis through interaction with serum factors such as EGF, PDGF and/or LBP.

• Tuberculosis and Respiratory Diseases
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• v.40 no.3
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• pp.223-235
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• 1993

Background: Superoxide anion which was produced by macrophage and neutrophil has a defensive role to kill invasive microorganisms and also an injurious role to produce self lung damage. Production of oxygen free radicals including superoxide is a main mechanism of acute lung injury caused by bacterial endotoxin. Endotoxin is known to activate alveolar macrophage to produce increased oxygen free radicals after the stimulation with various biological materials (priming effect). Calcium is a very important intracellular messenger in that cellular process of superoxide production. Method: This experiment was performed to elucidate the effects of endotoxin and calcium on superoxide production by phorbol myristate acetate-stimulated alveolar macrophage and the effect of verapamil on priming effect of endotoxin. Results: 1) Preincubation of macrophages with endotoxin (E. coli 055-B5) primed the cells to respond with increased superoxide production after the stimulation with PMA. Priming with endotoxin ($10^{-1}$ug/ml) produced a maximal enhancement of superoxide production (43%). 2) Verapamil could inhibit the superoxide production by PMA stimulated macrophage regardless of the presence of extracellular calcium. This means that the inhibitory effect of verapamil is caused by a mechanism independent of blocking calcium influx. 3) Verapamil could inhibit the priming effect of endotoxin on alveolar macrophage (from 30% increment to 13% increment) and could inhibit the superoxide production by PMA-stimulated macrophage preincubated with endotoxin. Conclusion: We concluded that verapamil could inhibit the superoxide production by PMA-stimulated rat alveolar macrophage and also inhibit the priming effect of endotoxin on alveolar macrophage. These inhibitory effects of verapamil could be one of the mechanisms of verapamil effects on endotoxin induced lung injury.

• Toxicological Research
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• v.9 no.2
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• pp.241-251
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• 1993

Present studies were carried out in order to estabilish the bronchoalveolar lavage method and to examine the response of bleomycin and peplomycin on the total cell number and the subpoulations of bronchoalveolar lavage fluid. A total of 24 male F344 rats, weighing 300-350 mg, were divided into 3 groups. Animals recelved either belomycin (BLM` 0.75 mg/0.2 ml/rat), peplomycin (PLM` 0.25mg/0.2ml/rat) for groups 2 and 3 or an equal volume of sterile saline lacking drugs for controls (group 1).

• 대한상한금궤의학회지
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• v.13 no.1
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• pp.21-44
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• 2021

Objective : This study aimed to assess the preventive effect of Bupleuri Radix aqueous extracts (BR) and red koji-fermented BR (fBR) in lipopolysaccharide (LPS)-induced acute lung injury in a rat model. Methods : Rats were administered 30, 60, or 120 mg/kg/day of fBR for 28 days before LPS treatments. All rats were sacrificed 5 h after LPS treatment (500 ㎍/head, intratracheal instillation). Body weights, lung weights, pulmonary transcapillary albumin transit, arterial gas parameters (pH, partial pressure [Pa] of O2, PaCO2), bronchoalveolar lavage fluid (BALF) protein, lactate dehydrogenase (LDH), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), total cell numbers, neutrophil/alveolar macrophage ratios, lung malondialdehyde (MDA), and myeloperoxidase (MPO) were measured. In addition, histopathological changes including the luminal surface of alveoli (LSA), thickness of alveolar septum, and number of polymorphonuclear neutrophils (PMNs) were checked. Results : LPS injection led to increases in lung weights, pulmonary transcapillary albumin transit, BALF protein, LDH, TNF-α and IL-1β contents, total cells, neutrophil and alveolar macrophage ratios, lung MDA, MPO, alveolar septum thickness, and PMNs, and decreases in PaCO2 and pH of arterial blood and LSA. However, these LPS-induced acute lung injuries were inhibited by pretreatment of 30, 60, and 120 mg/kg of fBR. The most favorable effects were seen with 30 mg/kg fBR as compared with 60 mg/kg of α-lipoic acid and BR. Conclusions : fBR showed preventive effects on LPS-induced acute lung injury, which resembles acute respiratory distress syndrome. The mechanisms of action were likely via antioxidant and anti-inflammatory means.

• Tuberculosis and Respiratory Diseases
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• v.39 no.6
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• pp.526-535
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• 1992

Background: The oxygen radicals released by alveolar macrophages contribute to killing of microorganisms including M. tuberculosis. Macrophages are "primrd" for enhanced oxygen radical release by macrophage activator like IFN-$\gamma$ and LPS, which do not themselves cause release of oxygen radicals. Actural production of oxygen radicals is "triggered" by phagocytosis or by exposure to chemical stimuli like PMA or FMLP. There has been debates about the priming effect of alveolar macro phages because they are exposed to usual environmental particles unlike blood monocytes. Therefore we examined priming effect of IFN-$\gamma$ in human alveolar macrophages comparing with that in blood monocytes and rat alveolar macrophages. And we observed the alterations of superoxide production in both human and rat alveolar macrophages after exposure to M. tuberculosis H37Ra bacilli itself and its lysate. Methods: Bronchoalveolar lavage fluid was processed to isolate alveolar macrophages by adherence and the adherent cells were removed by cold shock method. After exposure to M. tuberculosis H37Ra strain, alveolar macrophages were incubated for 24 hours with IFN-$\gamma$. The amount of superoxide production stimulated with PMA was measured by ferricytochrome C reduction method. Results: 1) The priming effect in human alveolar macrophages was not observed even with high concentration of IFN-$\gamma$ while it was observed in blood monocytes and rat alveolar macrophages. 2) Both human and rat alveolar macrophages exposed to avirulent H37Ra strain showed triggering of superoxide release and similar results were shown with the exposure to H37Ra lysate. Conclusion: The priming effect in human alveolar macrophages is not observed because of its usual exposure to environmental particles and avirulent H37Ra strain does not inhibit the activation of alveolar macrophages.