• The Korean Journal of Physiology and Pharmacology
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• 제4권3호
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• pp.219-226
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• 2000

In order to elucidate the role of platelet activating factor (PAF) in the acute lung injury induced by endotoxin (ETX), activities of phospholipase A2, lyso PAF acetyltransferase and oxidative stress by neutrophilic respiratory burst were probed in the present study. To induce acute lung injury, $100\;{\mu}g$ of E.coli ETX (type 0127; B8) was instilled directly into the tracheae of Sprague-Dawley rats. Five hours after the ETX instillation, induction of acute lung injury was confirmed by lung leak index and protein contents in the bronchoalveolar lavage (BAL) fluid. At the same time, lung phospholipase A2 (PLA2) activity and expression of group I and II secretory type PLA2 were examined. In these acutely injured rats, ketotifen fumarate, known as lyso PAF acetyltransferase inhibitor and mepacrine were administered to examine the role of PAF in the pathogenesis of the acute lung injury. To know the effect of the ETX in the synthesis of the PAF in the lungs, lyso PAF acetyltransferase activity and PAF content in the lungs were measured after treatments of ETX, ketotifen fumarate and mepacrine. In addition, the role of neutrophils causing the oxidative stress after ETX was examined by measuring lung myeloperoxidase (MPO) and enumerating neutrophils in the BAL fluid. To confirm the oxidative stress in the lungs, pulmonary contents of malondialdehyde (MDA) were measured. After instillation of the ETX in the lungs, lung leak index increased dramatically (p＜0.001), whereas mepacrine and ketotifen decreased the lung leak index significantly (p＜0.001). Lung PLA2 activity also increased (p＜0.001) after ETX treatment compared with control, which was reversed by mepacrine and ketotifen (p＜0.001). In the examination of expression of group I and II secretory PLA2, mRNA synthesis of the group II PLA2 was enhanced by ETX treatment, whereas ketotifen and WEB 2086, the PAF receptor antagonist, decreased the expression. The activity of the lysoPAF acetyltransferase increased (p＜0.001) after treatment of ETX, which implies the increased synthesis of PAF by the remodelling of lysoPAF in the lungs. Consequently, the contents of the PAF in the lungs were increased by ETX compared with control (p＜0.001), while mepacrine (p＜0.001) and ketotifen (p＜0.01) decreased the synthesis of the PAF in the lungs of ETX treated rats. The infiltration of the neutrophils was confirmed by measuring and enumerating lung MPO and the neutrophils in the BAL fluid respectively. Compared with control, ETX increased lung MPO and number of neutrophils in BAL significantly (p＜0.001) whereas mepacrine and ketotifen decrerased number of neutrophils (p＜0.001) and MPO (p＜0.05, p＜0.001, respectively). The lung MDA contents were also increased (p＜0.001) by ETX treatment, but treatment with mepacrine (p＜0.001) and ketotifen (p＜0.01) decreased the lung MDA contents. Collectively, we conclude that ETX increases PLA2 activity, and that the subsequently increased production of PAF was ensued by the remodelling of the lyso PAF resulting in tissue injury by means of oxidative stress in the lungs.

• 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.

• 약학회지
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• 제47권2호
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• pp.69-77
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• 2003

Arachidonic acid (AA), which is stored in membrane glycerophospholipids, is liberated by phospholipase $A_2$ (PLA$_2$) enzymes and is sequentially converted to cyclooxygenases (COXs) and lipoxygenases (LOXs) then to various bioactive PGs, and LTs. In order to find the specific inhibitors of AA metabolism especially PLA$_2$, COX-2, 5-LO and lyso PAF acetyltransferase, 120 Korean residential plants extracts were evaluated for their inhibitory activity on PGD$_2$, LTC$_4$ production from cytokine-induced mouse bone marrow-derived mast cells (BMMC) and arachidonic acid released from phospholipid and PAF production from lyso PAF. From this screening procedure, methanol extract of ten indigenous plant such as Salix gracilistyla, Sedum kamtschaticum, Cirsium chanroenicum, Hypericum ascyron, Astilbe chinensis, Agrimonia pilosa, Aristolochia manshuriensis, Vodia daniellii, Pyrola japonica, Styrax obassia were found to inhibit production of inflammatory mediators in vitro assay system.

• Tuberculosis and Respiratory Diseases
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• 제45권2호
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• pp.369-379
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• 1998

연구배경: Platelet-activating factor (PAF)는 염증반응의 중요한 매개체이며, 폐혈관의 투과성을 증가시키고, 급만성 폐동맥 고혈압을 유발하며 leukotriene의 합성을 촉진시킨다. 또한 PAF는 호중구의 화화주성, 응집, 탈과립 및 유착과 leukotriene $C_4$, $D_4$ 및 superoxide anion의 생산에도 영향을 미친다. PAF는 혈소판의 응집과 thromboxane $A_2$의 생산을 초래하여 혈액 응고를 촉진시키며 폐혈관계의 미소색전을 일으켜 폐 손상 발생의 주요원인 중 하나이다. 이와같은 현상은 PAF을 흡입후에도 유사한 반응들이 일어나는 것이 관찰된다. PAF는 급성 호흡곤란 증후군(acute respiratory distress syndrome, ARDS)의 병인에 중요한 매개체 중 하나로 알려져 있다. Surfactant는 폐 방어기전에 영향을 미치는데 첫째, surfactant protein-A(SP-A)와 대식세포간 상호작용이 적절한 대식세포 기능 유지에 중요하다. 둘째, surfactant는 수많은 염증에 관여되는 매개체들을 적절이 조정하며 셋째, surf actant 단백자체가 중요한 산화방지능이었으며 넷째, 호기시 폐포밖으로 외부에서 흡입된 각종 업자(불순물들을 제거한다. 이 중 어느하나에 장애가 오면 ARDS의 병인에 중요한 영향을 미친다. 방 법: PAF를 백서 기도내 투여후 surfactant단백 A, B 및 C의 mRNA 발현 양상을 filter hybridization방법으로 조사하여 surfactant단백 A, B 및 C 유전자 발현에 대한 PAF의 효과를 관찰하여 다음과 같은 결과를 얻었다. 결 과: SP-A mRNA양은 PAF투여군에서 대조군 및 Lyso-PAF투여군에 비하여 각각 37.1% 및 41.6% 유의하게 감소하였다 (p<0.025, p<0.01). SP-B mRNA양은 PAF투여군에서 대조군 및 Lyso-PAF 투여군에 비하여 각각 18.7% 및 32.2% 감소하였으나, 유의한 차는 없었다. SP-C mRNA양은 PAF투여군에서 대조군 및 Lyso-PAF투여군에 비하여 각각 30.7% 및 38.5% 유의하게 감소하였다(p<0.01, p<0.01). 결 론: 이상의 결과로 SP-A, B, C mRNA에 대한 PAF의 억제효과를 확인 하였으며 이와같은 surfactant단백들의 발현에 대한 PAF의 억제효과가 급성 호흡곤란증후군의 병인의 한요인으로 작용할 수 있을것으로 생각된다.

• The Korean Journal of Physiology and Pharmacology
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• 제1권2호
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• pp.201-208
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• 1997

It is becoming increasingly clear that the inflammatory reaction can be ascribed to a complex array of mediators generated and released from activated phagocytes. In this study, the effect of PAF on interleukin-1(IL-1) activity by rat alveolar macrophages(AM) was examined using thymocyte proliferation assay in the supernate of sample obtained after 24 hr culture. When AM were cultured with PAF alone, no change in IL-1 activity was observed. However, the combined addition of PAF and muramyl dipeptide(MDP) or lipopolysaccharide(LPS) to AM cultures markedly enhanced IL-1 activity by 2-3 fold compared with AM cultures with the stimulant alone in a concentration dependent fashion. The peack effect was found at $10^{-8}$ M PAF with MDP and $10^{-14}$ M PAF with LPS. the effect of PAF was also tested in silica, toxic respirable dust, -added AM cultures as well as in the cultures containing bacterial compounds. Although silica did not stimulate the IL-1 activity, PAF could enhance IL-1 activity by 2 fold above the value of the silica-treated AM cultures with the peak response at $10^{-12}$ M PAF. Optimal enhancement of IL-1 activity occured when MDP and PAF were present together at the initiation of the 24 hr AM cultures. Additionaly, the biologically inactive precursor/metabolite of PAF, lyso-PAF failed to induce enhancement of IL-1 activity. When the specific, but structurally different PAF receptor antagonists, BN 52021($10^{-5}$ M) and CV 3988($10^{-5}$ M) was treated 15 min before addition of PAF($10^{-8}$ M) and MDP$(10\;{\mu}g/ml)$ to the AM cultures, it markedly inhibited the enhancement of IL-1 activity induced by PAF. The effects of these PAF antagonists were also observed in LPS$(10\;{\mu}g/ml)$-stimulated cells. Collectively, these data suggest that PAF enhances IL-1 activity by interaction with a specific receptor.

• Tuberculosis and Respiratory Diseases
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• 제58권3호
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• pp.276-284
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• 2005

연구배경 : 호중구는 급성 폐손상에서 폐장내 염증반응에 중추적인 역할을 하는 것으로 알려져 있다. 호중구가 조직손상을 유발하기 위해서 폐모세혈관내로 격리(sequestration), 유착(adhesion) 및 화학주성 (chemotaxis)에 의한 폐장내의 간질 (interstitium)쪽으로의 이동 (migration)등의 과정을 거치며, 유착분자는 이 과정에서 호중구의 혈관내피세포에의 결합을 매개한다. 한편 폐손상에서 remodeling 경로를 통해 생성되는 PAF은 호중구 침윤에 화학유인물질로 작용하고 호중구의 유착과 활성화를 자극한다. 이에 근거하여 본 연구에서는 내독소로 유도된 의한 급성 폐손상에서 ketotifen을 사용하여 PAF remodelling을 억제하거나 fucoidan을 이용하여 유착분자를 억제함으로써 호중구에 의한 산화성 스트레스 감소에 따르는 폐손상 억제 효과를 확인하고자 하였다. 방 법 : 체중 300g 내외의 수컷 Sprague-Dawley에서 대장균 내독소의 기도내 투여로 급성 폐손상을 유도하고 PAF remodeling 및 유착분자의 억제 효과를 보기 위해 각각 ketotifen fumarate와 fucoidan을 내독소 투여 전 복강내 주사하였다. 각 군에서 단백 누출지수, 폐장내 MPO 활동도, 기관지 폐포세척액내 호중구수와 lyso PAF AT 활성도를 측정하였고 폐장의 미세 구조적 변화 및 산소기 생성을 관찰하였다. 결 과 : 내독소 투여군에서 대조군과 비교하여 단백 누출지수, 폐장내 MPO 활동도, 기관지 폐포세척액내 호중구수, 폐장내 lyso PAF AT 활성도가 증가하였고 조직내 호중구의 침윤 및 산소기 생성이 현저하여 폐손상이 유발되었음을 알 수 있었다. ketotifen 투여군에서는 내독소 투여군에 비해 단백 누출지수, 폐장내 MPO 활동도, 기관지 폐포세척액내 호중구 수, 폐장내 lyso PAF AT 활성도가 감소하였으며 조직학적 변화도 경감되었다. 반면 fucoidan 투여군에서는 단백 누출지수, 기관지 폐포세척액내 호중구 수의 감소를 보이지 않았고 내독소에 의한 조직학적 변화의 경감도 보이지 않았다. 결 론 : 내독소에 의한 급성 폐손상에서 PAF remodeling의 억제는 호중구에서 산소기 생성을 감소시켜 폐장 내산화성 스트레스를 감소, 이에 따라 폐손상을 경감시킬 것으로 생각되며 fucoidan에 의한 유착분자의 억제는 내독소에 의한 폐장 내 손상, 특히 호중구에 의한 손상을 억제하지 못하는 것으로 미루어 단순히 fucoidan을 이용하여 유착분자 활성화를 억제하는 것만으로는 폐손상을 경감시키는 효과가 없을 것으로 사료된다.

• 약학회지
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• 제43권1호
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• pp.117-123
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• 1999

Because of the potent effects of lipid mediators such as prostaglandins (PGs), leukotriens (LTs) and platelet activating factor (PAF) on a variety of cells and tissues, they are considered as major contributors to the process leading to inflammation and allergy. To pursue the mechanism of anti-inflammatory activity of Lonicera japonica, we tested inhibitory effects of 7 flavonoids from Lonicera japonica on arachidonic acid cascade related enzymes, such as inflammatory phospholipase $A_2$, cyclooxygenase-1 and 2, 5-lipoxygenase, in bone marrow derived mast cell (BMMC), and lyso PAF-acetyltransferase in rat spleen microsomes. Anti-inflammatory activities of lonicera japonica are thought to be attributed at least in part to the inhibition of arachidonic acid cascade releated enzymes by flavonoids such as apigenin, luteolin quercetin.

• 생약학회지
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• 제34권1호통권132호
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• pp.109-117
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• 2003

Arachidonic acid(AA), which is stored in membrane glycerophospholipids, is liberated by phospholipase $A_2(PLA_2)$ enzymes and is sequentially converted to cyclooxygenase (COX) and lipoxygenase (LOX) then to various bioactive prostaglandins (PGs,) and leukotrienes (LTs). In order to find the specific inhibitors of AA metabolism enzymes such as $PLA_2$, COX-2, 5-LO and lyso PAF acetyltransferase. 195 Korean indigenous plant extracts were evaluated for their inhibitory activity on $PGD_2,\;LTC_4$ production from cytokine-induced mouse bone marrow-derived mast cells (BMMC) and arachidonic acid released from phospholipid and PAF production from lyso PAF. From this screening procedure, methanol extract of eight plants such as Saururus chinensis, Aster tataricus, Chrysanthemum cinerariaefolium, Reynoutria japonica, Disocorea nipponica, Epimedium koreanum, impatiens textori, Veronica rotunda var. subintegra were found to inhibit production of inflammatory mediators in vitro assay system.

• The Korean Journal of Physiology and Pharmacology
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• 제3권4호
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• pp.405-414
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• 1999

The role of platelet-activating factor (PAF) was investigated in intestinal ischemia/reperfusion (I/R) induced acute lung injury associated with oxidative stress. To induce acute lung injury following intestinal I/R, superior mesenteric arteries were clamped with bulldog clamp for 60 min prior to the 120 min reperfusion in Sprague-Dawley rats. Acute lung injury by intestinal I/R was confirmed by the measurement of lung leak index and protein content in bronchoalveolar lavage (BAL) fluid. Lung leak and protein content in BAL fluid were increased after intestinal I/R, but decreased by WEB 2086, the PAF receptor antagonist. Furthermore, the pulmonary accumulation of neutrophils was evaluated by the measurement of lung myeloperoxidase (MPO) activity and the number of neutrophils in the BAL fluid. Lung MPO activity and the number of neutrophils were increased (p＜0.001) by intestinal I/R and decreased by WEB 2086 significantly. To confirm the oxidative stress induced by neutrophilic respiratory burst, gamma glutamyl transferase (GGT) activity was measured. Lung GGT activity was significantly elevated after intestinal I/R (p<0.001) but decreased to the control level by WEB 2086. On the basis of these experimental results, phospholipase $A_2\;(PLA_2),$ lysoPAF acetyltransferase activity and PAF contents were measured to verify whether PAF is the causative humoral factor to cause neutrophilic chemotaxis and oxidative stress in the lung following intestinal I/R. Intestinal I/R greatly elevated $PLA_2$ activity in the lung as well as intestine (p<0.001), whereas WEB 2086 decreased $PLA_2$ activity significantly (p<0.001) in both organs. LysoPAF acetyltransferase activity, the PAF remodelling enzyme, in the lung and intestine was increased significantly (p<0.05) also by intestinal I/R. Accordingly, the productions of PAF in the lung and intestine were increased (p<0.001) after intestinal I/R compared with sham rats. The level of PAF in plasma was also increased (p<0.05) following intestinal I/R. In cytochemical electron microscopy, the generation of hydrogen peroxide was increased after intestinal I/R in the lung and intestine, but decreased by treatment of WEB 2086 in the lung as well as intestine. Collectively, these experimental results indicate that PAF is the humoral mediator to cause acute inflammatory lung injury induced by intestinal I/R.

• 대한약학회:학술대회논문집
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• 대한약학회 2000년도 NEW STRATEGY FOR DRUG DEVELOPMENT IN POST-GENOMIC ERA(대한약학회)
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• pp.223.2-223.2
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• 2000