• Tuberculosis and Respiratory Diseases
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• 제69권4호
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• pp.256-264
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• 2010

Background: According to the notion of the immunoregulatory functions of moxifloxacin (MFX), the effect of MFX on the neutrophilic respiratory burst in conjunction with the expression of cytosolic phospholipase $A_2$ ($cPLA_2$) was investigated. Methods: The effects and possible mechanisms of MFX on neutrophilic respiratory burst in oleic acid (OA)-induced acutely injured rats lung and OA-stimulated, isolated murine neutrophils were probed, associated with the expression of cytosolic phospholipase $A_2$ in vivo and in vitro. Results: In the OA-induced acutely-injured lungs, neutrophils were accumulated, which was attenuated by MFX. The parameters denoting a neutrophilic respiratory burst, such as nitro blue tetrazolium reaction, cytochrome-c reduction, neutrophil aggregation, $H_2O_2$ production in neutrophils revealed increased neutrophilic respiratory burst by OA, and MFX decreased all of these parameters. In addition, the enhanced expression of $cPLA_2$ in the lung and isolated murine neutrophils by OA were decreased by MFX. Conclusion: MFX suppresses the OA-induced neutrophilic respiratory burst by the suppression of $cPLA_2$ in neutrophils.

• Tuberculosis and Respiratory Diseases
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• 제68권2호
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• pp.55-61
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• 2010

Background: The underlying pathogenesis of fat embolism-induced acute lung injury (ALI) has not been elucidated. In the present study, the pathogenesis of fat embolism-induced ALI was probed in association with neutrophilic oxidative stress in oleic acid (OA)-induced ALI of S-D rats. Methods: OA was injected intravenously to provoke ALI in experimental rats. Five hours later, indices of ALI were measured to confirm the role of the neutrophilic respiratory burst. The effect of an inhibition of phospholipase A2 (PLA2) was also evaluated. Results: The accumulation of neutrophils in the lung due to OA caused increased neutrophilic oxidative stress in lung, which was ameliorated by mepacrine. What were the results from inhibition of PLA2. Conclusion: Excess neutrophilic oxidative stress contributes to OA-induced ALI, which is lessened by the inhibition of PLA2.

• Tuberculosis and Respiratory Diseases
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• 제48권6호
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• pp.887-897
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• 2000

연구배경 : 급성호흡부전증후군(ARDS)의 병인론을 호중구의 산소기 생성 및 apoptosis 의 관정에서 PLA2 및 PAF의 역할과 연관하여 알아보았다. ARDS의 원인 중 산소기의 역할이 주로 염증성 cytokine 및 지질분자와 관련하여 연구되고 있는 점에 착안하여 내독소에 의한 PLA2, PAF의 작용 및 이에 따른 호중구의 혈관내피세포로의 유착, 산소기에 의한 pulmonary surfactant의 기능에 미치는 영향에 대해서도 알아보았다. 방법 : PMA로 자극된 호중구에서 PLA2 및 PAF의 억제에 따른 산소기 형성의 변화에 대해서도 알아보았으며 내독소에 의한 호중구에서의 PLA2활동도의 변화, lysoPAF remodelling에 미치는 PLA2 및 PAF의 억제의 효과에 대해서도 알아보았다. 또한 내독소 및 PMA에 의해 자극된 상태에서의 PLA2 및 PAF의 억제가 호중구의 apoptosis에 미치는 영향도 알아보았다. 호중구에 의한 조직의 손상은 혈관내피세포로의 호중구의 유착이 선행되어야 하므로 이러한 작용에 PLA2 및 PAF가 미치는 영향을 호중구 유착검사를 통하여 알아보았고 형태학적으로는 산소기와 pulmonary surfactant의 결합을 확인하였다. 결론 : ARDS 시의 호중구의 역할은 PLA2 및 PAF의 작용에 의한 산소기 형성 및 염증성 지질분자의 생성을 통해 조작의 손상을 유발하는 듯하며 이때 PLA2의 억제는 호중구의 apoptosis의 증가 및 산소기의 생성을 감소시키고 또한 호중구의 혈관내피세포로의 유착을 감소시켰다. PAF의 억제는 호중구의 산소기 생성의 감소 및 호중구의 유착을 억제하여 조직의 손상을 감소시키는 것으로 생각되었다.

• Tuberculosis and Respiratory Diseases
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• 제51권6호
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• pp.503-516
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• 2001

연구배경 : 급성 출혈성 쇼크에서 발생하는 급성폐손상의 병인론을 호중구의 산소기 생성과 연관하여 규명하고자 본 연구를 시행하였다. 급성출혈성쇼크에서 폐장내 산소기 생성의 주된 원인이 호중구의 침윤에 의한 것이며 이 때 PLA2의 활성화가호중구의 respiratory burst의 직접적인 원인임올 밝히고지 하였다. 방 법 : 체중 300-350 g 정도의 흰쥐에서 체중/kg 당 20ml정도의 혈액을 5분 동안 뽑아내어 급성 출혈성 쇼크를 유발하고 이 출혈성 쇼크 상태를 1시간 동안 유지하였다. 그 후 급성 폐손상의 지표들을 측정하였다. 동시에 폐장의 미세구조의 변화 및 세포화학적인 검사를 통하여 폐장조직내의 산소기의 형성을 확인하였다. 또한 PLA2 억제제인 mepacrine을 출혈직전에 투여하여 PLA2의 억제에 따른 변화도 검사, 비교하였다. 결 과 : 급성 출혈성 쇼크에 의해 유도된 급성 폐손상에서 호중구의 폐장내 침윤이 확인되었고 이 때 폐부종 및 조직내 산소기 형성의 증가가 관찰되었으며, 폐장내 PLA2의 활성도도 증가하였다. 그러나 mepacrine을 이용하여 PLA2를 억제한 결과, 폐부종의 감소, 산소기 형성의 감소가 확인되었다. 결 론 : 급성 출혈성 쇼크에 의한 급성폐손상은 호중구에 의한 산화성스트레스가 그 원인으로 생각되고 이 때 호중구에 의한 산화성스트레스의 발생에는 PLA2가 주된 역할을 한다고 사료된다.

• The Korean Journal of Physiology and Pharmacology
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• 제2권4호
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• pp.479-491
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• 1998

In order to know the pathogenesis of adult respiratory distress syndrome (ARDS) in association with the oxidative stress by neutrophils, the role of platelet activating factor (1-0-alkyl-2-acetyl-snglycero-3-phosphocholine, PAF) was investigated during acute lung injury induced by interleukin- $1{\alpha}$ (IL-1) in rats. An insufflation of IL-1 into the rat's trachea increased the acetyltransferase activity in the lung and the increase of PAF content was followed. As evidences of acute lung injury by neutrophilic respiratory burst, lung leak index, myeloperoxidase activity, numbers of neutrophils in the bronchoalveolar lavage fluid, neutrophilic adhesions to endothelial cells and NBT positive neutrophils were increased after IL-1 treatment. In addition, a direct instillation of PAF into the trachea caused acute lung leak and the experimental results showed a similar pattern in comparison with IL-1 induced acute lung injury. For the confirmation of oxidative stress during acute lung leak by IL-1 and PAF, a histochemical electron microscopy was performed. In IL-1 and PAF treated lungs of rats, the deposits of cerrous perhydroxide were found. To elucidate the role of PAF, an intravenous injection of PAF receptor antagonist, WEB 2086 was given immediately after IL-1 or PAF treatment. WEB 2086 decreased the production of hydrogen peroxide and the acute lung leak. In ultrastructural study, WEB 2086 mitigated the pathological changes induced by IL-1 or PAF. The nuclear factor kappa B (NFkB) was activated by PAF and this activation was inhibited by WEB 2086 almost completely. Based on these experimental results, it is suggested that the PAF produced in response to IL-1 through the remodeling pathway has the major role for acute lung injury by neutrophilic respiratory burst. In an additional experiment, we can also come to conclude that the activation of the NFkB by PAF is thought to be the fundamental mechanism to initiate the oxidative stress by neutrophils causing release of proinflammatory cytokines and activation of phospholipase $A_2$.

• Tuberculosis and Respiratory Diseases
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• 제68권6호
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• pp.334-344
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• 2010

Background: Based on the known immunoregulatory functions of moxifloxacin on phagocytes, the therapeutic effect of moxifloxacin on oleic acid (OA)-induced acute lung injury (ALI) was investigated. Methods: Moxifloxacin (10 mg/kg) was given to male Sprague-Dawley rats that had been given oleic acid (OA, $30{\mu}L$) intravenously. Five hours after OA injection, parameters demonstrating ALI were assessed to measure the effects of moxifloxacin on acute lung injury. Results: The pathological findings of OA-induced ALI's was diminished by moxifloxacin. Through ultrastructural and $CeCl_3$ EM histochemistry, moxifloxacin was confirmed to be effective in decreasing oxidative stress in the lung as well. Indices of ALI, such as lung weight/body weight ratio, protein content in bronchoalveolar lavage fluid, and lung myeloperoxidase were decreased by moxifloxacin. In diaminobenzidine immunohistochemistry, fluorescent immunohistochemistry, and Western blotting of the lung, moxifloxacin had decreased the enhanced expression of secretory phospholipase $A_2$ ($sPLA_2$) by OA. Conclusion: We concluded that moxifloxacin was effective in lessening acute inflammatory pulmonary edema caused by OA, by inhibiting the neutrophilic respiratory burst, which was initiated by the activation of $sPLA_2$.

• The Korean Journal of Physiology and Pharmacology
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• 제3권3호
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• pp.263-273
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• 1999

The role of phospholipase $A_2\;(PLA_2)$ in acute lung leak induced by intestinal ischemia was investigated in association with neutrophilic respiratory burst. To induce lung leak, we generated intestinal ischemia for 60 min prior to the 120 min reperfusion by clamping superior mesenteric artery in Sprague-Dawley rats. Acute lung leak was confirmed by the increased lung leak index and protein content in bronchoalveolar fluid. These changes were inhibited by mepacrine, the non-specific $PLA_2$ inhibitor. The lung myeloperoxidase (MPO) activity denoting the pulmonary recruitment of neutrophils was increased by intestinal I/R, but decreased by mepacrine. Simultaneously, the number of leukocytes in bronchoalveolar fluid was increased by intestinal ischemia/reperfusion (I/R) and decreased by mepacrine. Gamma glutamyl transferase activity, an index of oxidative stress in the lung, was increased after intestinal I/R but decreased by mepacrine, which implicates that $PLA_2$ increases oxidative stress caused by intestinal I/R. The $PLA_2$ activity was increased after intestinal I/R not only in the intestine but also in the lung. These changes were diminished by mepacrine. In the cytochemical electron microscopy to detect hydrogen peroxide, intestinal I/R increased the generation of the hydrogen peroxide in the lung as well as in the intestine. Expression of interleukin-1 (IL-1) in the lung was investigated through RT-PCR. The expression of IL-1 after intestinal I/R was enhanced, and again, the inhibition of $PLA_2$ suppressed the expression of IL-1 in the lung. Taken together, intestinal I/R seems to induce acute lung leak through the activation of $PLA_2$, the increase of IL-1 expression associated with increased oxidative stress by neutrophilic respiratory burst.

• Tuberculosis and Respiratory Diseases
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• 제48권2호
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• pp.246-259
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• 2000

연구배경: 패혈증에 의해 발병하는 ARDS의 기전은 아직까지 명확히 알려져 있지 않다. 특히 패혈증시 폐 혈관내피세포 및 제 1, 2형 폐포세포의 손상이 호중구의 respiratory burst에 따른 oxidative stress에 의한 것인지는 아직도 논란의 대상이다. 또한 이때 oxidative stress의 직접적인 원인인 산소기 생성기전도 명확하지가 않다. 본 연구에서는 패혈증에 의한 ARDS 발병기전을 $PLA_2$의 작용과 호중구의 산소기 생성을 연관시켜 알아보고자 하였다. 방 법: Sprague-Dawley종 흰쥐에서 diethylmaleate(DEM)를 이용하여 glutathione을 고갈시킨 뒤 내독소를 기도 내로 분무하여 급성 폐손상을 유발하였다. 이때 oxidative stress를 평가할 수 있는 방법들, 즉 단백누출지수, 폐세척액 내 단백함량, 폐장 내 myelo-peroxidase(MPO)의 활동도 malondialdehyde(MDA)의 측정 및 GGT의 활성도를 측정하고 동시에 oxidative stress에 관여하는 $PLA_2$의 역할을 확인하기 위하여 비특이적 $PLA_2$ 억제제인 mepacrine(50mg/kg)을 복강 내 투여한 후 폐장 내 $PLA_2$의 활성도를 측정하였다. 또한 미세구조적 변화 및 세포화학적인 방법을 통해 조직 내 산소기의 생성을 확인, 비교하여 산소기 형성에 관여하는 $PLA_2$의 역할을 규명하였다. 결 과: Diethylmaleate에 의해 폐장 내 glutathione을 고갈시킨 뒤 내독소를 투여한 흰쥐에서, 내독소는 폐장 내 현저한 조직의 손상을 유발하였고, 동시에 oxidative stress의 증가를 관찰하였다. 즉 lipid peroxidation의 증가 및 GGT 활성도의 증가를 관찰하였다. 이러한 변화들은 폐장 내 호중구 침윤의 증가 및 $PLA_2$ 활성도와 관계가 있음을 확인하였고, 미세구조적 및 세포화학적인 방법으로 조직 내의 산소기 형성의 증가도 관찰하였다. 이러한 변화들이 비특이적 $PLA_2$ 억제제인 mepacrine의 작용에 의해 감소하는 것으로 미루어 보아 $PLA_2$가 내독소에 의한 oxidative stress에 관여한다고 생각되었다. 결 론: 내독소에 의해 유발되는 급성 폐손상에서 조직손상의 원인은 호중구의 respiratory burst에 따른 oxidative stress임을 확인하였고 이때 oxidative stress에 $PLA_2$의 활성화에 따라 생성되는 지질분자가 그 원인으로 사료되었다.

• The Korean Journal of Physiology and Pharmacology
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• 제2권5호
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• pp.617-628
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• 1998

In order to understand the pathogenetic mechanism of adult respiratory distress syndrome (ARDS), the role of phospholipase A2 (PLA2) in association with oxidative stress was investigated in rats. $Interleukin-1{\alpha}\;(IL-1,\;50\;{\mu}g/rat)$ was used to induce acute lung injury by neutrophilic respiratory burst. Five hours after IL-1 insufflation into trachea, microvascular integrity was disrupted, and protein leakage into the alveolar lumen was followed. An infiltration of neutrophils was clearly observed after IL-1 treatment. It was the origin of the generation of oxygen radicals causing oxidative stress in the lung. IL-1 increased tumor necrosis factor (TNF) and cytokine-induced neutrophil chemoattractant (CINC) in the bronchoalveolar lavage fluid, but mepacrine, a PLA2 inhibitor, did not change the levels of these cytokines. Although IL-1 increased PLA2 activity time-dependently, mepacrine inhibited the activity almost completely. Activation of PLA2 elevated leukotriene C4 and B4 (LTC4 and LTB4), and 6-keto-prostaglandin $F2{\alpha}\;(6-keto-PGF2{\alpha})$ was consumed completely by respiratory burst induced by IL-1. Mepacrine did not alter these changes in the contents of lipid mediators. To estimate the functional changes of alveolar barrier during the oxidative stress, quantitative changes of pulmonary surfactant, activity of gamma glutamyltransferase (GGT), and ultrastructural changes were examined. IL-1 increased the level of phospholipid in the bronchoalveolar lavage (BAL) fluid, which seemed to be caused by abnormal, pathological release of lamellar bodies into the alveolar lumen. Mepacrine recovered the amount of surfactant up to control level. IL-1 decreased GGT activity, while mepacrine restored it. In ultrastructural study, when treated with IL-1, marked necroses of endothelial cells and type II pneumocytes were observed, while mepacrine inhibited these pathological changes. In histochemical electron microscopy, increased generation of oxidants was identified around neutrophils and in the cytoplasm of type II pneumocytes. Mepacrine reduced the generation of oxidants in the tissue produced by neutrophilic respiratory burst. In immunoelectron microscopic study, PLA2 was identified in the cytoplasm of the type II pneumocytes after IL-1 treatment, but mepacrine diminished PLA2 particles in the cytoplasm of the type II pneumocyte. Based on these experimental results, it is suggested that PLA2 plays a pivotal role in inducing acute lung injury mediated by IL-1 through the oxidative stress by neutrophils. By causing endothelial damage, functional changes of pulmonary surfactant and alveolar type I pneumocyte, oxidative stress disrupts microvascular integrity and alveolar barrier.

• Tuberculosis and Respiratory Diseases
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• 제63권6호
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• pp.497-506
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• 2007

연구배경: 급성호흡곤란증후군의 병인론에 관여하는 PAF의 역할이 다양하고 중요하므로 본 연구에서는 PAF의 또 다른 작용의 가능성, 즉 $cPLA_2$의 활성화(retrograde activation of $cPLA_2$ by PAF)의 가능성을 검사하고자 하였다. 즉, $cPLA_2$의 활성화에 따른 염증성 지질분자의 생성이 산소기의 생성과정을 증폭시키고 이 때 생성된 PAF가 역으로 $cPLA_2$를 활성화시키는지를 확인하기 위하여 본 연구는 고안되었다. 방 법: 흰쥐에서 급성폐손상을 유도하기 위하여 $5{\mu}g$의 PAF를 0.5 ml의 0.25% bovine serum albumin 용액과 혼합한 뒤 기도 내로 직접 분무하거나 0.5 ml의 4.5 mM의 과산화수소를 기도 내로 분무하였다. 대조군의 경우는 0.5 ml의 생리적 식염수를 기도 내로 분무하였다. 5 시간 후에 단백누출지수 측정, 폐장의 MPO 활성도 측정, 폐포 세척액 내의 호중구 산정, CINC 측정, NBT 및 cytochrome-c 환원검사를 시행하였다. 또한 폐장 및 호중구에 서의 $cPLA_2$ 활성도의 측정 및 광학현미경과 전자현미경을 이용하여 형태학적 관찰을 시행하였다. 결 과: PAF투여 후 단백누출지수, MPO, BAL내의 호중 구의 수 및 CINC의 농도가 대조군에 비하여 유의하게 증가하였다. NBT및 cytochrome-c환원검사의 결과 PAF는 호중구의 respiratory burst를 현저히 증가시키고, 분리된 사람의 호중구에서도 산소기의 생성을 현저히 증가시켰 다. 동시에 PAF는 분리된 호중구 및 폐장의 $cPLA_2$의 활성도도 증가 시켰다. 폐장 내로 투여한 과산화수소는 폐장의 $cPLA_2$활성도를 대조군에 비하여 현저히 증가시켰다. 결 론: $cPLA_2$의 활성화에 따라 생성된 PAF는 호중구의 산소기 생성을 증가시켜 폐장 내의 산화성스트레스를 유발하고 동시에 이때 생성된 산화기는 $cPLA_2$를 활성화시키며 PAF 또한 $cPLA_2$의 활성도를 증가시켜 PAF가 급성호흡 곤란증후군의 병인론에 관여하는 것으로 생각된다.