Elevated Platelet Activating Factor Level in Ischemia-Related Arrhythmia and Its Electrophysiological Effect on Myocardium

Objective The mechanism through which platelet activating factor （PAF） induces cardiac electrical activity and arrhythmia is not well understood and previous studies have suggested a potential involvement of ion channels in its action. The present study was aimed to clarify the role of PAF in fatal arrhythmias following acute myocardia infarction （AMI） and the underlying mechanism. Methods （1） Blood PAF levels were measured among 72 AMI patients at the time of diagnosis with AMI and 48 h later, and their electrocardiogram （ECG） was recorded continuously. （2） Ischemia simulation and surface electrocardiogram were conducted in 20 pigs and their PAF levels were measured. （3） PAF perfusion and standard microelectrode recording were performed on guinea pig papillarymuscles. Results In both humans and pigs, elevated PAF levels were detected in AMI and simulated ischemia, respectively, and even higher PAF levels were found when fatal arrhythmias occurred. In guinea pig myocardium, PAF induced a shortening of action potential duration at 90% level of repolarization （APD 90 ）under non-ischemic conditions and a more pronounced shortening under early simulated ischemic conditions. Conclusion AMI and ischemia are associated with increased PAF levels in humans and pigs, which are further raised when fatal arrhythmia follows. The effects of PAF on the myocardium may be mediated by multiple ion channels.

Pathogenetic effects of platelet activating factor on enterogenic endotoxemia after burn

INTRODUCTION Previous clinical and experimental studies haveindicated that an early endotoxemia occurred after amajor burn.It is unlikely that burn wound sepsis isthe source of circulating endotoxin in less than 12hour after burn.Increasing evidence demonstratesthat the bacteria and endotoxin in thegastrointestinal tract can pass through the gutbarrier into blood circulation to form enterogenicendotoxemia following burn.However。

Therapy for acute pancreatitis with platelet-activating factor receptor antagonists

Acute pancreatitis (AP) causes release of platelet- activating factor (PAF), which induces systemic effects that contribute to circulatory disturbances and multiple organ failure. PAF is a cell surface secretion of bioactive lipid, which could produce physiological and pathological effects by binding to its cell surface receptor called platelet-activating factor receptor (PAF-R). Studies showed that PAF participates in the occurrence and development of AP and administration of platelet-activating factor receptor antagonists (PAF-RAs) could significantly reduce local and systemic events after AP. PAF has also been implicated as a key mediator in the progression of severe AP, which can lead to complications and unacceptably high mortality rates. Several classes of PAF-RA show PAF- RAs significant local and systemic effects on reducing inflammatory changes. As a preventive treatment, PAF-RA could block a series of PAF-mediated inflammatory injury and thus improve the prognosis of AP. This review introduces the important role of PAF-RA in the treatment of AP.

Role of platelet-activating factor in pathogenesis of acute pancreatitis

Platelet-activating factor(PAF)is a potentproinflammatory phospholipid mediator that belongsto a family of biologically active,structurally relatedalkyl phosphoglycerides with diverse pathologicaland physiological effects.This bioactive phospholipidmediates processes as diverse as wound healing,physiological inflammation,angiogenesis,apoptosis,reproduction and long-term potentiation.PAF actsby binding to a specific G protein-coupled receptorto activate multiple intracellular signaling pathways.Since most cells both synthesize and release PAFand express PAF receptors,PAF has potent biologicalactions in a broad range of cell types and tissues.Inappropriate activation of this signaling pathway isassociated with many diseases in which inflammationis thought to be one of the underlying features.Acutepancreatitis(AP)is a common inflammatory disease.The onset of AP is pancreatic autodigestion mediatedby abnormal activation of pancreatic enzyme caused bymultiple agents,which subsequently induce pancreaticand systemic inflammatory reactions.A number ofexperimental pancreatitis and clinical trials indicatethat PAF does play a critical role in the pathogenesisof AP.Administration of PAF receptor antagonist cansignificantly reduce local and systemic events that occurin AP.This review focuses on the aspects that are morerelevant to the pathogenesis of AP.

Sequential expression of cyclooxygenase-2, glutamate receptor-2, and platelet activating factor receptor in rat hippocampal neurons after fluid percussion injury

Traumatic brain injury causes gene expression changes in different brain regions. Occurrence and development of traumatic brain injury are closely related, involving expression of three factors, namely cyclooxygenase-2, glutamate receptor-2, and platelet activating factor receptor. However, little is known about the correlation of these three factors and brain neuronal injury. In this study, primary cultured rat hippocampal neurons were subjected to fluid percussion injury according to Scott’s method, with some modifications. RT-PCR and semi-quantitative immunocytochemical staining was used to measure the expression levels of cyclooxygenase-2, glutamate receptor-2, and platelet activating factor receptor. Our results found that cyclooxygenase-2 expression were firstly increased post-injury, and then decreased. Both mRNA and protein expression levels reached peaks at 8 and 12 hours post-injury, respectively. Similar sequential changes in glutamate receptor 2 were observed, with highest levels mRNA and protein expression at 8 and 12 hours post-injury respectively. On the contrary, the expressions of platelet activating factor receptor were firstly decreased post-injury, and then increased. Both mRNA and protein expression levels reached the lowest levels at 8 and 12 hours post-injury, respectively. Totally, our findings suggest that these three factors are involved in occurrence and development of hippocampal neuronal injury.

Significance of platelet activating factor receptor expression in pancreatic tissues of rats with severe acute pancreatitis and effects of BN52021

AIM:To investigate the dynamic changes and significance of platelet activating factor receptor (PAF-R) mRNA and protein in pancreatic tissues of rats with severe acute pancreatitis (SAP) and effects of BN52021 (Ginkgolide B). METHODS:Wistar male rats were randomly assigned to the negative control group (NC group),SAP model group (SAP group),and BN52051-remedy group (BN group),and each of the groups was divided into 6 subgroups at different time points after operation (1 h,2 h,3 h,6 h,12 h,and 24 h) (n=10 in each). PT-PCR and Western blot methods were used to detect PAF-RmRNA and protein expression in pancreatic tissues of rats respectively. Pathological examination of pancreatic tissues was performed and the serum amylase change was detected. RESULTS:Serum amylase and pathological results showed the that SAP model was successfully prepared,BN52021 was able to decrease serum amylase,and the pathological ratings in BN group at 3 h,6 h,and 12 h significantly decreased compared with those in the SAP group (8.85 ± 0.39 vs 5.95 ± 0.19,9.15 ± 0.55 vs 5.55 ± 0.36,10.10 ± 0.65 vs 6.72 ± 0.30,P < 0.05). The result of PAF-mRNA showed dynamic changes in SAP and BN groups,which increased gradually in early stage,reached a peak at 3 h (0.71 ± 0.14 vs 0.54 ± 0.14,0.69 ± 0.13 vs 0.59 ± 0.04,P < 0.05),and decreased gradually later. There were significant differences at each time point except 1 h and 2 h,when compared with those in the NC group (0.71 ± 0.14 or 0.69 ± 0.13 vs 0.47 ± 0.10,0.38 ± 0.08 or 0.59 ± 0.04 vs 0.47 ± 0.09,0.25 ± 0.07 or 0.29 ± 0.05 vs 0.46 ± 0.10,0.20 ± 0.06 or 0.20± 0.04 vs 0.43 ± 0.09,P < 0.05),whereas there was no significant difference between BN and SAP groups at each time point. The result of PAF-R protein showed that the change of PAF-R protein in the SAP group and the BN group was consistent with that of PAF-R mRNA. There were significant differences at each time point except 1 h,when compared with those in the NC group (0.90 ± 0.02 or 0.80 ± 0.05 vs 0.48 ± 0.02,1.69 ± 0.06 or 1.58 ± 0.02 vs 0.48 ± 0.03,1.12 ± 0.10 or 0.98 ± 0.03 vs 0.49 ± 0.09,1.04 ± 0.14 or 0.87 ± 0.02 vs 0.52 ± 0.08,0.97 ± 0.16 or 0.90 ± 0.05 vs 0.49 ± 0.10,P < 0.05),whereas there was no significant difference between the BN group and the SAP group. CONCLUSION:PAF-R plays an important role in occurrence and development of SAP. BN52021 exerts biological effects through competitively inhibiting the binding of increased both PAF and PAF-R expression rather than through decreasing PAF-R expression in pancreatic tissues.

Role of platelet-activating factor in reproduction:sperm function

Since its discovery nearly thirty years ago, platelet-activating factor has emerged as one of the more important lipidmediators known. Platelet-activating factor (PAF; 1-O-alkyl-2-O-acetyl-sn-glycero-3-phosphorylcholine) exists en-dogenously as a mixture of molecular species with structural variants of the alkyl moiety. PAF is a novel potent signal-ing phospholipid that has unique pleiotropic biological properties in addition to platelet activation. PAF also plays a sig-nificant role in reproduction. PAF content in squirrel monkey sperm is significantly higher during the breeding seasonthan the non-breeding season. PAF content in human sperm has a positive correlation with seminal parameters and preg-nancy outcomes. High-fertility boars have significantly more PAF in their sperm than low-fertility boars. The enzymes(lyso-PAF-acetyltransferase and PAF-acetylhydrolase) necessary for PAF activation and deactivation are present insperm. PAF-acetylhydrolase may act as a 'decapacitation factor'. Removal of this enzyme during capacitation maypromote PAF synthesis increasing motility and fertilization. PAF also plays a significant role in the fertilization process,enhancing the fertilization rates of oocytes. Enhanced embryo development has also been reported in oocytes fertilizedwith PAF-treated sperm. PAF antagonists inhibit sperm motility, acrosome reaction, and fertilization, thus suggestingthe presence of receptors for PAF. The PAF-receptor is present on sperm, with altered transcript levels and distributionpatterns on abnormal cells. Whereas the exact mechanism of PAF in sperm function and reproduction is uncertain, itsimportance in normal fertility is substantial. The reproductive significance of PAF activity in sperm and fertility plus therole of PAF in the establishment of pregnancy requires further study.

Platelet-activating factor in cirrhotic liver and hepatocellular carcinoma

瞄准：激活血小板的因素(PAF ) 是一个支持 inflammatory 和 angiogenic 类脂化合物调停人。这里，我们试图调查 PAF 的层次， lyso-PAF ( PAF 先锋)，磷脂酶 A ( 2 )( PLA ( 2 )，产生 lyso-PAF 的酶的活动)， acetylhydrolase 活动(啊哈， PAF 降级的酶)并且在硬变肝和肝细胞癌( HCC )的 PAF 受体( PAF-R )抄本。方法：有 HCC 的 29 个病人在这研究被注册。肝硬化在十四个病人是在场的，七没有肝疾病。织物 PAF 层次被血小板聚集试金调查。Lyso-PAF 在它的化学乙酰化作用以后被估计进 PAF。啊哈被降级决定[(3 ) H ]-PAF。PLA (2 ) 层次被 EIA 估计。PAF-R 抄本用 RT-PCR 被调查。结果：PAF 和 PAF-R 抄本的提高的数量(白血球类型) 1 作为与非肝脏硬化症的相比在肝脏硬化症的纸巾被发现。PAF 和 PAF-R 抄本的更高的数量(织物类型) 1 和 2 作为与非肿瘤纸巾相比在 HCC 纸巾被发现。PLA (2 ) ， lyso-PAF 和啊哈层次没在肝脏硬化症的纸巾和 HCC 被改变。结论：当 PAF 的角色在肝生理学当前是未知的时，这研究在在 HCC 期间在硬变肝并且在 angiogenic 反应发现的煽动性的网络建议它的潜在的参与。

Synthesis of platelet-activating factor and its receptor expression in Kupffer cells in rat carbon tetrachloride-induced cirrhosis

AIM:To determine the platelet-activating factor (PAF) synthesis and its receptor expression in Kupffer cells in rat carbon tetrachloride-induced cirrhosis. METHODS:Kupffer cells, isolated from the livers of control and CCl4-induced cirrhotic rats, were placed in serum-free medium overnight. PAF saturation binding, ET-1 saturation and competition binding were assayed. ET-1 induced PAF synthesis, mRNA expression of PAF, preproendothelin-1, endothelin A (ETA) and endothelin B (ETB) receptors were also determined. RESULTS:A two-fold increase of PAF synthesis (1.42 ± 0.14 vs 0.66 ± 0.04 pg/μg DNA) and a 1.48-fold increase of membrane-bound PAF (1.02 ± 0.06 vs 0.69 ± 0.07 pg/μg DNA) were observed in activated Kupffer cells of cirrhotic rats. The application of ET-1 to Kupffer cells induced PAF synthesis in a concentration-dependent manner in both cirrhotic and normal rats via ETB receptor, but PAF synthesis in the activated Kupffer cells was more effective than that in the normal Kupffer cells. In activated Kupffer cells, PAF receptor expression and PAF binding capacity were markedly enhanced. Activated Kupffer cells raised the [125I]-ET-1 binding capacity, but changed neither the affinity of the receptors, nor the expression of ETA receptor. CONCLUSION:Kupffer cells in the course of CCl4-induced cirrhosis are the main source of increased PAF. ET-1 is involved endogenously in stimulating the PAF synthesis in activated Kupffer cells via ETB receptor by paracrine. ETA receptor did not appear in activated Kupffer cells, which may exacerbate the hepatic and extrahepatic complications of cirrhosis.

Effect of increased hepatic platelet activating factor and its receptor portal hypertension in CCl_4-induced liver cirrhosis

瞄准：为了在肝的血小板激活评估变化，肝脏硬化症的老鼠的门压力上的因素(PAF ) 和它的受体和他们的效果由 CCl4 导致了。方法：肝肝硬化的一个模型被 CCl4 的 intra 腹注射为 8 wk 在老鼠复制。我们由 EIA，浸透绑定和 RT-PCR 技术在门和动脉压上决定了肝的 PAF 和它的受体水平的效果。结果：比较了控制老鼠，肝脏硬化症的老鼠象更高的血浆 PAF 层次一样有更高肝的 PAF 层次和产量(P【0.01， P【0.01， P【0.05，分别地) 。两肝的 PAF 受体 mRNA 层次和 PAF 绑定是将近在肝脏硬化症的老鼠(P【0.01 ) 更大的 3 褶层。PAF (1 g/kg WT ) 的门注射分别地在控制和肝脏硬化症的老鼠增加了门压力 22% 和 33% 。相反，动脉压在两个组被减少(54% 在控制老鼠并且 42% 在肝脏硬化症的老鼠) 。PAF 对手 BN52021 (5 mg/kg WT ) 的注射减少了在肝脏硬化症的老鼠的在 16% 的门压力但是没在控制老鼠有效果。结论：起来 PAF 系统的规定在肝硬化贡献肝的血液动力学、新陈代谢的畸形，并且进发行量的 PAF 的增加的版本在全身的血液动力学上有影响。

Effect of Buyang Huanwu Decoction on Platelet Activating Factor Content in Arterial Blood Preand Post-Arterial Thrombosis in Rats

To explore the effect of Buyang Huanwu Decoction (BHD) on platelet activating factor (PAF) content in arterial blood pre- and post-arterial thrombosis in rats, male Wistar rats were randomly divided into 3 groups, the medicine group treated with BHD, the control group with dexamethasone liquid, and the blank group with distilled water. Oral administration was given for 14 consecutive days, once daily. Model of arterial thrombosis was established in the animals 2 hours after final medication, the blood content of PAF, dry weight (DW) and occlusion time (OT) of thrombus, and dry weight of thrombus/body weight (TW/BW) ratio were observed. Results indicated that BHD could markedly lower the arterial blood content of PAF after thrombosis, increase the OT of thrombus, reduce the dry weight of thrombus and the TW/BW ratio (P<0.05). It is suggested that BHD can inhibit the pathologic PAF metabolism and formation and development of arterial thrombus.

Roles of BN52021 in platelet-activating factor pathway in inflammatory MS1 cells

AIM: To determine the effects of BN52021 on platelet-activating factor receptor (PAFR) signaling molecules under lipopolysaccharide (LPS)-induced inflammatory conditions in MS1 cells. METHODS: MS1 cells (a mouse pancreatic islet endothelial cell line) were grown in Dulbecco's modified Eagle's medium supplemented with 10% fetal bovine serum, 2 mmol/L glutamine and 100 μg/mL penicillin/streptomycin in 5% CO 2 at 37 ℃. After growth to confluency in media, the cells were processed for subsequent studies. The MS1 cells received 0, 0.1, 1 and 10 μg/mL LPS in this experiment. The viability/prolifera-tion of the cells induced by LPS was observed using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide colorimetric assay. Apoptosis and necrosis of the cells under the inflammatory condition described previously were observed using Hoechst 33342-propidium iodide staining. Adenylate cyclase (AC), phospholipase A 2 (PLA 2 ), phospholipase Cβ (PLCβ), protein tyrosine kinase (PTK), G protein-coupled receptor kinases (GRK) and p38-mitogen-activated protein kinase (p38 MAPK) mRNA in the PAFR signaling pathway were measured by real-time polymerase chain reaction. The protein expression level of phosphorylated AC (p-AC), phosphorylated PLA 2 (p-PLA 2 ), phosphorylated PTK (p-PTK), phosphorylated p38 MAPK (p-p38 MAPK), PLCβ and GRK was measured using Western blotting analysis. RESULTS: The activity of MS1 cells incubated with dif- ferent concentrations of LPS for 6 h decreased significantly in the 1 μg/mL LPS group (0.49 ± 0.10 vs 0.67 ± 0.13, P < 0.05) and 10 μg/mL LPS group (0.44 ± 0.10 vs 0.67 ± 0.13, P < 0.001), but not in 0.1 μg/mL group. When the incubation time was extended to 12 h (0.33 ± 0.05, 0.32 ± 0.03 and 0.25 ± 0.03 vs 0.69 ± 0.01) and 24 h (0.31 ± 0.01, 0.29 ± 0.03 and 0.25 ± 0.01 vs 0.63 ± 0.01), MS1 cell activity decreased in all LPS concentration groups compared with the blank control (P < 0.001). BN52021 significantly improved the cell activity when its concentration reached 50 μmol/L compared with the group that received LPS treatment alone, which was consistent with the results obtained from fluorescence staining. The mRNAs levels of AC (4.02 ± 0.14 vs 1.00 ± 0.13), GRK (2.63 ± 0.03 vs 1.00 ± 0.12), p38 MAPK (3.87 ± 0.07 vs 1.00 ± 0.17), PLA 2 (3.31 ± 0.12 vs 1.00 ± 0.12), PLCβ (2.09 ± 0.08 vs 1.00 ± 0.06) and PTK (1.85 ± 0.07 vs 1.00 ± 0.11) were up-regulated after LPS stimulation as compared with the blank control (P < 0.05). The up- regulated mRNAs including AC (2.35 ± 0.13 vs 3.87 ± 0.08), GRK (1.17 ± 0.14 vs 2.65 ± 0.12), p38 MAPK (1.48 ± 0.18 vs 4.30 ± 0.07), PLCβ (1.69 ± 0.10 vs 2.41 ± 0.13) and PLA 2 (1.87 ± 0.11 vs 2.96 ± 0.08)were significantly suppressed by BN52021 except for that of PTK. The level of p-AC (1.11 ± 0.12 vs 0.65 ± 0.08), GRK (0.83 ± 0.07 vs 0.50 ± 0.03), PLCβ (0.83 ± 0.16 vs 0.50 ± 0.10) and p-p38 MAPK (0.74 ± 0.10 vs 0.38 ± 0.05) was up-regulated after LPS stimulation as compared with the blank control (P < 0.05). The up-regulated proteins, including p-AC (0.65 ± 0.15 vs 1.06 ± 0.14), GRK (0.47 ± 0.10 vs 0.80 ± 0.06), PLCβ (0.47 ± 0.04 vs 0.80 ± 0.19) and p-p38 MAPK (0.30 ± 0.10 vs 0.97 ± 0.05), was significantly suppressed by BN52021, but p-PLA 2 and p-PTK protein level were not suppressed. CONCLUSION: BN52021 could effectively inhibit LPS-induced inflammation by down-regulating the mRNA and protein levels of AC, GRK, p38 MAPK, PLA 2 and PLCβ in the PAFR signaling pathway.

Hepatic stellate cells may be potential effectors of platelet activating factor induced portal hypertension

AIM: To determine platelet activating factor (PAF) receptor expression in cirrhotic hepatic stellate cells.METHODS: Hepatic stellate cells, isolated from the livers of control and CCl4-induced cirrhotic rats, were placed in serum-free medium after overnight culture. We determined the PAF receptor in hepatic stellate cells by saturation binding technique and semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR), and the effects of PAF and its antagonist BN52021 on prostaglandin E2 (PGE2) release by stellate cells.RESULTS: Scatchard analysis indicated the presence of PAF receptor with dissociation constant (Kd) of 4.66 nmol/L and maximum binding capacity (Bmax) of 24.65 fmol/μg in cirrhotic stellate cells. Compared with the control, the maximum PAF binding capacity increased significantly (Bmax: 24.65 ± 1.96 fmol/μg. DNA, R = 0.982 vs 5.74 ± 1.55 fmol/μg. DNA, R = 0.93; P < 0.01), whereas receptor affinity had no significant difference (Kd of 4.66 ± 0.33 nmol/L for the cirrhosis and 3.51 ± 0.26 nmol/L for the control; P > 0.05). Consistent with the receptor binding data, the mRNA expression of PAF receptor was increased significantly in cirrhotic stellate cells. PAF in a concentration-dependent manner induced PGE2 synthesis in cirrhotic hepatic stellate cells, but the effects were blocked significantly by BN52021.CONCLUSION: Cirrhosis sensitizes hepatic stellate cells to PAF by elevating its receptor level and hepatic stellate cells maybe potential effectors of PAF induced portal hypertension.

Creation of reversed phase high-performance liquid chromatographic technique to assay platelet-activating factor

Objective: To establish a new assay for platelet-activating factor (PAF), to compare it with bio-assay; and to discuss its significance in some elderly people diseases such as cerebral infarction and coronary heart disease. Methods: To measure PAF levels in 100 controls, 23 elderly patients with cerebral infarction and 65 cases with coronary heart disease by reversed phase high-performance liquid chromatographic technique (rHPLC). Results:rHPLC is more convenient, sensitive,specific, and less confusing, compared with bio-assay. The level of plasma PAF in patients with cerebral infarction was higher than that in the controls (P<0.01), and in patients with coronary heart disease. Conclusion: Detection of PAF with rHPLC is more reliable and more accurate. The new assay has important significance in PAF research.

Effects of platelet-activating factor on endothelial cell monolayer permeability under hydrostatic perfusion in vitro

A simple and rapid method was established to study vascular permeability by in vitroperfused endothelial cell monolayers cultured on micropore filter membrane.It can be used todetermine filtration coefficient （Kf） to small molecules and osmotic reflection coefficient （σ） toproteins of the endothelial monolayer.Hanks’ balanced salt solution （HBSS） or 5g/L albuminin HBSS was used to perfuse the confluent endothelial monolayer at the hydrostatic pressure of2.45kPa （25cm H2O）.Control Kf values were 10.1±0.75 and 3.6±0.75μl·min-1·cm-2·kPa（-1）（±,n=3） respectively for the perfusion of HBSS and albumin HBSS,suggesting that al-bumin may decrease endothelial monolayer permeability to water and small molecules.After ex-posure of endothelial monolayer to 10-8mol/L platelet-activating factor （PAF） for 30min,Kfvalues increased to 193.1% and 133.3% respectively.Protein clearance rate (μl.min-1·cm-2)and osmotic reflection coefficient of the control endothelial monolayer were 8.0±3.22 and 0.37±0.09 respectively and those of the PAF treated endothelial monolayer 12.2±2.95μl·min-1·cm-2 and 0.18±0.06,revealing increased permeability to albumin.Computer-assisted imageprocessing demonstrated that PAF treatment decreased cell area while increased cell form factorand intercellular space,suggesting that endothelial cells retracted and rounded,which may bean important mechanism of PAF-induced increase of vascular permeability.

In vitro effects of buyang huanwu decoction and its ingredients on inhibiting the specific binding of ~3H-platelet activating factor to its receptor in rabbits

BACKGROUND： Pharmacologic action of traditional Chinese medicine compound is the comprehensive effect of various ingredients, and the interactions of various ingredients are closely correlated with the final effect. In order to reveal the compatibility mechanism of buyang huanwu decoction （BHD）＇s prescription in treating and preventing ischemic cerebrovascular disease, we need to explore the effect and relation of ingredients in prescription except for considering the effect of each ingredient on the whole prescription. OBJECTIVE： To study the effect of BHD and its ingredients in the prescription on the specific binding of 3H-platelet activating factor （PAF） to its receptor （PAFR）in rabbits in vitro, and to analyze the action of each ingredient in the prescription. DESIGN： A decomposed recipe study based on orthogonal test. SETTING： Guangzhou University of Traditional Chinese Medicine. MATERIALS： Five healthy adult New Zealand rabbits of either gender were provided by the Experimental Animal Center of Guangzhou University of Traditional Chinese medicine. The prescription herbal pieces were purchased from Foshan Kangpu Pharmaceuticals Company and Jianmin Pharmaceuticals Company, and were appraised by Professor Yanchen Xu from College of Traditional Chinese Medicine, Guangzhou University of Traditional Chinese Medicine. 3H-PAF was supplied by Amersham Co,Ltd.（Specific activity： 6.475 TBq/mmol;batch number：200402）; PAF standard by Biomol Co., Ltd.（batch number： P1318V）. METHODS： This experiment was carried out in the Laboratory of Nuclear Medicine, Guangzhou University of Traditional Chinese Medicine between September and December 2004. ①The seven influencing factors were selected： such as Shenghuangqi , Dangguiwei, Chishao, Dilong, Taoren, Honghua, Chuanxiong. Each factor was divided into two levels, selected or not selected. The tests were arranged according to L8 （27） orthogonal test table. ②The specific binding of 3H-PAF to its receptors in rabbits was measured by radioligand binding assay. The inhibitory rate of the specific binding was used as an assessing index. The inhibitory action of and on 3H-PAF to PAFR binding was analyzed and compared in vitro. The inhibitory action of each ingredient in the prescription BHD on 3H-PAF to PAFR binding was investigated and compared in vitro by direct analysis and analysis of variance of orthogonal test. MAIN OUTCOME MEASURES： Effect of 8 prescriptions for L8 （27） orthogonal test table on the specific binding inhibition rate of 3H-PAF and PAFR. RESULTS： According to results of variance analysis of orthogonal test, the inhibitory action of each ingredient in the prescription BHD on 3H-PAF to PAFR binding from the highest to the lowest was in turn Honghua, ShenghuangqL Taoren, Dilong, DangguiweL Chuanxiong, Chishao. Honghua, Shenghuangqi, Taoren, Dilong, Danguiwei were major influence factors to 3H-PAF to PAFR in rabbits （F = 187.829,144.446,59.521,5.018,4.265, P 〈 0.05- 0.01）, but Chuanxiong and Chishao had not obviously inhibitory effect. The specific binding inhibition rate of prescriptions （except Shenghuangqi ） was obviously higher than that of one of prescriptions （Shenghuangqi included）. CONCLUSION： The results of orthogonal test show that Honghua, ShenghuangqL Taoren, Dilong, Dangguiwei are major influencing factors to inhibit binding of sH-PAF to PAFR in rabbits, among which, Honghua is the strongest in ingredients of prescription BHD. The results also reveal that Shenghuangqi is able to weaken the inhibitory effect and to prevent the strong inhibitory effect of blood-activating drugs in BHD.

Effect of platelet activating factor on blood spinal cord barrier following cervical cord injury

Effect of platelet activating factor(PAF) on blood spinal cord barrier in cervical cord injury was investigated. Methods: Spinal cord injury at C6 segment was induced with Allen’s ’method in cats. PAF and PAF receptor antagonist BN52021 were administered by arachnoid space and intravenous injection respectively, and their effects on PAF levels, blood spinal cord barrier and cervical cord edema in the injuried zone and adjacent cervical cord tissue following cervical cord injury were investigated. Results: PAF levels, Evens content and water content in the injuried and adjacent cervical cord tissues significantly increased following trauma. PAF levels, Evens content and water content were evidently elevated with PAF by arachnoid space injection. PAF receptor antagonist BN52021 could inhibit the increase in PAF levels and reduce Evens and water content in the cervical cord tissue following trauma. Conclusion: PAF is an important contributing factor causing post-traumatic damage to the blood spinal cord barrier, while PAF receptor antagonist can effectively relieve post-traumatic damage to the blood spinal cord barrier.

INTRACAMERAL INJECTION OF PLATELET ACTIVATING FACTOR AS A MEDIATOR OF INTRAOCULAR INFLAMMATION IN RABBIT EYES

Objective To evaluate platelet activating factor (PAF) induced aqueous liare, corneai edema, pupillary constriction and btphasic intraocular pressure (IOP) changes in the rabbit eyes. Methods PAF was delivered into anterior chamber by intracameral injection, other antagonists were administered systemically. Results PAF induced responses in a dose - dependent manner. All of the responses to PAF were inhibited by the PAF receptor antagonist, BN 52021 (20mg/kg, i.p.). The cyclooxygenase inhibitor, indomethacin (30mg/kg, i.P.) caused signofcant inhibition of the early phase PAF- induced aqueous flare, pupillary constriction and intraocular hypertension, but did not alfect PAF- induced corneal edema or intraocular hypotension. Nordihydroguaiaretic acid (NDGA) (10mg/kg, ip.), a lipoxygenase inhibitor, did not inhibit the inflammatory effects of PAF. Conclusion These data suggest that PAF may be an important mediator of intraocular inllammation and that some PAF- induced effects are prostaglandin dependent, while others may be independent of eicosanoid synthesis and release.

Effects of Buyang Huanwu decoction and Astragalus mongholicus on platelet activating factor receptor activity in rabbits in vitro

BACKGROUND: The pharmacological action of traditional Chinese medicine compound is the comprehensive effect of the various ingredients, and the interactions of various ingredients are closely correlated with the final effect. In order to reveal the compatibility mechanism of BHD's prescription in treating and preventing ischemic cerebrovascular disease, we needed explore the effect and relation of ingredients in the prescription. OBJECTIVE: To observe the effect of Buyang Huanwu decoction (BHD) and Astragalus mongholicus on the activity of platelet activating factor receptor (PAFR) in the platelet of rabbits in vitro, and investigate the mechanism of Astragalus mongholicus. DESIGN: A decomposed recipes study. SETTING: Guangzhou University of Traditional Chinese Medicine. MATERIALS: Five New Zealand rabbits, weighing 2-3 kg, both sexes, were used. BHD was composed of Sheng Huang Qi 120 g, Dang Gui Wei 6 g, Chi Shao 4.5 g, Chuan Xiong 3 g, Di Long 3 g, Tao Ren 3 g, Hong Hua 3 g. The prescription for activating blood circulation consisted of Dang Gui Wei 6 g, Chi Shao 4.5 g, Chuan Xiong 3 g, Di Long 3 g, Tao Ren 3 g and Hong Hua 3 g. The prescription for invigorating qi consisted of 120 g Sheng Huang Qi. The prepared herbal pieces were purchased from the traditional Chinese medicine Dispensary of Foshan Second People's Hospital, and appraised by Professor Xu from Science of Chinese Materia Medica College, Guangzhou University of Traditional Chinese Medicine. 3H-PAF was supplied by Amersham Co., Ltd. (specific activity: 6. 475 TBq/mmol; batch number: 200402); PAF standard by Biomol Co., Ltd. (batch number: P1318V). METHODS: The experiments were carried out in the Laboratory of Nuclear Medicine, Guangzhou University of Traditional Chinese Medicine from September to December 2004. ① Injections of BHD, prescriptions for activating blood circulation and invigorating qi were prepared by the decoction and alcohol sedimentation technique. Rabbit common carotid artery blood (40 mL) was drawn via intubation to prepare platelet suspension of (0.8-1.0)×1010 L-1. ② Determination of 3H-PAF and washed PAFR binding: The general combination tube (T) contained washed platelet-rich plasma (WPRP) 380 μL + 3H-PAF (0.35 nmol/L)10 μL+distilled water 5 μL; The nonspecific binding tube (P) contained WPRP 380 μL+3H-PAF(0.35 nmol/L)10 μL+cold PAF (1 μmol/L) 5 μL; The sample tube (Y) contained WPRP 380 μL+3H-PAF(0.35 nmol/L)10 μL+experimental medicine (injection of BHD, prescriptions for activating blood circulation or invigorating qi) 5 μL. The test was conducted for three times for each sample in the same way as mentioned above. The samples were shaken on the oscillator for 30 s, then bathed at 25 ℃ for 40 minutes, and the reaction was terminated with cold Tris buffer containing 0.1% BSA, multichannel cell detachment separator was used for vacuum suction to filter the separated free 3H-PAF, and the filter paper was washed with cold Tris buffer for four times, then dried in the baking oven (80 ℃) for 1 hour, and placed in xylol liquid scintillator, and the radioactivity was determined automatically by the liquid scintillation detector. The mean of the three parallel tubes was calculated. The specific binging inhibition rate was calculated: SBIR=[(T-Y)/(T-P)]×100%]. ③ Univariate analysis of variance was conducted. And for comparison of each paired groups, the q test was adopted. MAIN OUTCOME MEASURES: Effect of BHD whole prescription, prescriptions for activating blood circulation and invigorating qi on the specific binding inhibition rate of 3H-PAF and PAFR. RESULTS: BHD, prescriptions for activating blood circulation and invigorating qi were all able to inhibit the specific binding of 3H-PAF to PAFR, the specific blinding inhibition rates were (45.90±7.50)%, (97.90±1.84)% and (26.75±2.48)%, respectively, and there were significant differences between every two groups (P < 0.01). CONCLUSION: Single Astragalus mongholicus (120 g) can inhibit the specific blinding of PAFR in the platelet of the rabbit with 3H-PAF, but the combination of Astragalus mongholicus with the drugs for activating blood circulation in BHD can significantly decrease the inhibiting action of the latter on PAFR activity of the platelet, reflecting the combined mechanism of 'removing blood stasis without injuring the vital qi' in BHD.

The actions,detection and synthesis of platelet-activating factor (PAF) in mammalian pregnancy

Platelet-activating factor (PAF) exhibits a variety of biological activities and it be thought to involved in various pathophysiological process. In this paper, some studies were summarized about those roles ofPAF in a variety productive processes of female of mammalian that inctude fertilization, implantation and parturition, and that was involved in the concentration, synthesis, deiradation and some assay methods of PAF. Therelationship between PAF and early pregnancy factor (EPF) was reviewed.