The effect of the selective PAF antagonist CIS-19 on PAF- and antigen-induced bronchoconstriction, microvascular leakage and bronchial hyperreactivity in guinea-pigs

We investigated the effects of a novel platelet-activating factor (PAF) receptor antagonist, CIS-19 [cis-2-(3, 4-dimethoxyphenyl)-6-isopropoxy-7-methoxy-1-(N-methylformamido)-1, 2, 3, 4-tetrahydronaphthalene], on PAF-, histamine-, substance P- and antigen-induced bronchoconstriction and microvascular leakage, as well as PAF- and antigen-induced bronchial hyperreactivity to methacholine in urethane-anesthetized guinea-pigs. Administration of CIS-19 (0.5–5 mg/kg, i.v.) inhibited the increase in lung resistance induced by PAF (30 ng/kg, i.v.) in a dose-dependent manner, but failed to inhibit the increase induced by histamine (30 μg/kg, i.v.) or substance P (6.5 μg/kg, i.v.). CIS-19 (5 mg/kg, i.v.) did not inhibit the increase in lung resistance induced by ovalbumin (2 mg/kg, i.v.) in actively sensitized guinea-pigs. PAF (30 ng/kg, i.v.)-induced microvascular leakage, measured by the extravasation of Evans blue dye, was dose-dependently inhibited by CIS-19 (0.5–5 mg/kg, i.v.) in the trachea, main bronchi and intrapulmonary airways, but it did not affect histamine (30 μg/kg, i.v.)- or substance P (6.5 μg/kg, i.v.)-induced microvascular leakage at all airway levels. CIS-19 (2.5 and 5 mg/kg) did not affect ovalbumin (2 mg/kg, i.v.)-induced microvascular leakage in all airway levels in actively sensitized guinea-pigs. CIS-19 (2.5 and 5 mg/kg, i.v.) significantly inhibited PAF-induced enhancement of the bronchial response to methacholine, but had no effect on ovalbumin (0.05 mg/kg, i.v.)-induced bronchial hyperreactivity in actively sensitized guinea-pigs. It is concluded that CIS-19 is a potent PAF receptor antagonist which inhibits PAF- but not antigen-induced bronchoconstriction, microvascular leakage and bronchial hyperreactivity. These results suggest that PAF plays little or no role in early airway responses following antigen challenge. Received: 29 April 1996 / Accepted: 10 October 1996     

The effect of the neurokinin antagonist FK-224 on the cough response to inhaled capsaicin in a new model of guinea-pig eosinophilic bronchitis induced by intranasal polymyxin B

Eosinophilic bronchitis without asthma can cause a persistent non-productive cough which is resistant to bronchodilator therapy. To understand the mechanism of the cough in this disorder, an animal model of eosinophilic bronchitis was developed. Guinea-pigs were treated with transnasal administration of polymyxin B or saline twice a week for 3 weeks. The number of eosinophils in bronchoalveolar lavage fluid increased in polymyxin B-treated animals when compared with those treated with saline. In addition, histological examination showed that the number of eosinophils infiltrated into the tracheal epithelium increased; injury to the tracheal epithelium was greater in polymyxin B-treated animals. The numbers of coughs induced by saline and each concentration of capsaicin (10^–18, 10^–16, 10^–14M) were greater in the polymyxin B-treated animals. FK-224 (a neurokinin receptor antagonist) decreased the heightened cough reflex in this animal model of eosinophilic bronchitis. These findings suggest that neuropeptides, and particularly neurokinins, are involved in the heightened cough receptor sensitivity in eosinophilic bronchitis without asthma. This has implications for better understanding of this disorder and its treatment.     

清胆胶囊对豚鼠胆色素结石模型的生化学影响

目的:观察清胆胶囊对豚鼠胆囊胆色素结石模型的生化学的影响。方法:应用雄性豚鼠建立胆色素结石模型(n=8),并设立正常对照组和清胆胶囊治疗组(均n=8),观察各组动物之间模型成石率、总胆红素(total bilirubin,TB)、游离胆红素(unconjugated bilirubin,UCB)、钙离子浓度等指标的变化。结果:动物成石数模型组为8/8,正常组为1/8,清胆胶囊组为3/8(P<0.001)。与模型组相比,清胆胶囊组总胆红素含量差异无统计学意义,游离胆红素和钙离子均显著降低(P<0.01,P<0.05)。结论:清胆胶囊可以通过降低胆汁中游离胆红素和钙离子含量逆转成石胆汁,发挥防治胆色素结石的作用。     

NF-κB活化阻断剂对盲肠结扎穿刺所致豚鼠急性肺损伤的预防与治疗

目的观察NF-κB活化阻断剂是否对盲肠结扎穿刺所致豚鼠急性肺损伤具有防治作用，探讨NF-κB活化阻断剂防治肠源性肺损伤的机制。方法用盲肠结扎穿刺（CLP）法建立豚鼠急性肺损伤模型，同时经口给予布洛芬167mg／kg和肌内注射维生素E174mg／kg预防和治疗，结合动脉血气分析、外周血白细胞计数、肺湿重／下重比值（W／D）及肺组织病理变化，免疫组化方法研究肺组织NF-κB的活化。结果CLP组动物在6h后开始缓慢出现症状，呼吸急促100～110次／min（正常呼吸80～95次／min），蜷缩，对外界刺激敏感；16h有少量泡沫状分泌物由鼻腔溢出，呼吸变得窘迫，倦怠，卧伏，不喜活动；24h呼吸窘迫十分显著，泡沫状分泌物（带血性）由鼻腔溢出明显增多，呼吸频率为100-140次／min；CLP24h内死亡率可达10％，24-40h死亡数可达30％，40～56h死亡数可达80％。动脉血氧分压（PaO2）在12h开始明显下降，24h以后有恶化趋势，PaO2持续低于10kPa，外周血白细胞计数从12h开始降低，24h明显降低。术后24h已经表现出急性肺损伤。肺组织NF-κB表达活跃。动物于2d左右出现大量死亡；给药组动物治疗和预防症状有缓解，预防组的最终死亡率为40％，治疗组为60％，肺组织NF-κB表达程度均较模型组低。结论在肺损伤早期联合应用NF-κB活化阻断剂进行预防，有助于提高ALI的存活率，能减缓肠源性肺损伤的发生和进展，减轻急性肺损伤症状，进而发挥阻止病程向多器官功能衰竭发展的重要作用，这种作用机制可能是通过抑制NF-κB活化实现的。     

沥青对豚鼠烧伤创面及其周围皮肤的影响

为了解沥青对烧伤及其周围皮肤的影响，进行３个内容不同的豚鼠实验：实验一观察沥青对正常皮肤的影响，发现“沥青皮肤”４８小时后的组织学和超微结构均发生严重病变，对照组正常。实验二观察沥青对烧伤创面的影响，发现沥青早期使烧伤创面扩大，其愈合速度、愈合创面毛囊数和真皮厚度均分别比对照组明显减慢、减少和变薄（Ｐ＜０．００１）。实验三观察沥青对溃疡创面的影响，发现早期沥青使溃疡创面广泛缺血坏死和炎性浸润，愈合后创面上皮组织增生明显。提示沥青对正常皮肤、烧伤和溃疡创面均有较强的腐蚀、刺激和破坏作用。因此，对沥青烧伤必须及早全面清创。     

一氧化氮、内皮素和循环内皮细胞在支气管哮喘中的作用研究

目的：探讨一氧化氮、内皮素和循环内皮细胞在支气管哮喘中的作用。方法：哮喘患儿６１例,４０名健康儿童为对照,测定其血浆ＮＯ－２／ＮＯ－３、ＥＴ、ｃＧＭＰ和循环内皮细胞（ＣＥＣ）水平,用过敏性哮喘豚鼠进行验证。结果：哮喘患儿血浆ＮＯ－２／ＮＯ－３、ｃＧＭＰ和ＣＥＣ水平均明显升高（Ｐ＜０．０５～００１）,其中重度哮喘患儿血浆ＮＯ－２／ＮＯ－３和ＣＥＣ水平较轻中度哮喘患儿更高（Ｐ均＜００１）;重度哮喘患儿血浆ＥＴ水平明显升高（Ｐ＜００１）;哮喘患儿血浆ＮＯ－２／ＮＯ－３与ｃＧＭＰ和ＣＥＣ水平呈显著正相关（Ｐ＜００５～００１）。过敏性哮喘豚鼠ＢＡＬＦ中ＮＯ－２／ＮＯ－３、ＥＴ及ｃＧＭＰ水平均明显升高（Ｐ均＜００１）;血浆中ｃＧＭＰ和ＣＥＣ水平亦升高（Ｐ均＜００５）;糖皮质激素可降低ＮＯ－２／ＮＯ－３、ＥＴ、ｃＧＭＰ和ＣＥＣ水平。结论：哮喘时ＮＯ－２／ＮＯ－３、ＥＴ和ＣＥＣ产生过多,它们在哮喘发病机制中占有重要地位,而且血浆ＥＴ和ＣＥＣ水平可能与哮喘病情相关。     

Effects of CIS-19, a novel PAF receptor antagonist,on PAF-induced eosinophil recruitment and enhancement of superoxide anion generation in guinea-pigs

We examined the effects of a novel plateletactivating factor (PAF) receptor antagonist, CIS-19 [cis-2-(3,4-dimethoxyphenyl)-6-isopropoxy-7-methoxyl-1-(N-methylformamido)-1,2,3,4-tetrahydronaphthalene], on PAF-induced inflammatory cells recruitment into airways and enhancement of superoxide anion (O _inf2 ^sup– ) generation from cells retrieved by bronchoalveolar lavage (BAL) in urethane-anesthetized guinea-pigs. Administration of PAF (30 ng/kg, Lv.) produced a selective increase of eosinophils into airways, but no significant increase of the number of macrophages, neutrophils or lymphocytes. CIS-19 (2.5 and 5 mg/kg, Lv.) significantly inhibited the eosinophil recruitment induced by PAF. In vitro, PAF, phorbol 12-myristate 13-acetate (PMA) and N-formyl-methionyl-leucyl-phenylalanine (FMLP) directly stimulated generation of O _inf2 ^sup– from BAL cells in a concentration-dependent manner. CIS-19 (10^–7 – 10^–4 M) inhibited production of O _inf2 ^sup– induced by PAF (10^–7 M) in a concentration-dependent manner with an EC₅₀ value of 0.84 M, but not induced by PMA (0.5 g/ml) or FMLP (10^–7 M). Administration of PAF (5 ng/kg, i.v.) enhanced markedly PMA (0.5 g/ml) and FMLP (10^–7 M)-induced generation of O _inf2 ^sup– by 80.2% and 51.3%, respectively. The enhancing effect of PAF was maximal in cells harvested 5 min after the addition of PAF and then declined to baseline level at 60 min. These responses were inhibited by administration of CIS-19 (0.5—2.5 mg/kg, i.v.) or BN 52021(5 mg/kg, i.v.). The results indicate that CIS-19 is potent in inhibition of PAF-induced airway inflammatory response and may have therapeutic potential as an anti-inflammatory drugs.     

绝对不应期电刺激对正常豚鼠和慢性心力衰竭豚鼠心室肌细胞动作电位及钠离子-钙离子交换的影响

目的:探讨绝对不应期电刺激(ARPES)对正常豚鼠和慢性心力衰竭(衰竭)豚鼠心室肌细胞动作电位(AP)及钠离子-钙离子(Na -Ca2 )交换的影响.方法:应用膜片钳技术中电流钳记录ARPES对AP时程的影响,再以不同的AP电压钳记录细胞膜Na -Ca2 交换电流.结果:①ABPES延长AP时程,以APD30最为显著(P＜0.01),差异有统计学意义.②与正常豚鼠心室肌细胞比较,衰竭豚鼠心室肌细胞AP的平台期明显不同,表现在APD90变化(P＜0.05)及APD50变化(P＜0.01),差异有统计学意义.③分别以基础刺激(S1)下的AP(APS1)和ARPES下的AP(APARPES)为测试电压,记录AP电压钳下的细胞膜Na -Ca2 交换电流,在正常豚鼠心室肌细胞,APARPES电压钳记录的单位膜电容下的外向电流强度的整合值高于APS1电压钳记录的相应值,而单位膜电容下的内向电流强度的整合值无显著变化.在衰竭豚鼠心室肌细胞,APARPES电压钳记录的单位膜电容下的外向电流强度的整合值明显高于APS1电压钳记录的相应值,而单位膜电容下的内向电流强度的整合值无显著变化.外向电流峰值的增加更为明显.结论:ARPES延长正常豚鼠和衰竭豚鼠心室肌细胞AP时程,对心室肌细胞膜Na -Ca2 交换电流的影响可能是其增强整体心脏收缩功能的机制之一.     

Relaxation of the guinea-pig trachea induced by platelet-activating factor and by serotonin

Platelet-activating factor (PAF-acether), a known platelet stimulant and bronchoconstrictor (in vivo), is a potential mediator of inflammation and trombosis. However, all smooth muscle effects of PAF-acether described to date are indirect, relying upon intravascular platelet activation. Novel actions of PAF-acether and serotonin (5-HT) are presented here; these actions may lead to the development of a practical bioassay for PAF-acether and contribute to the understanding of the mechanism of action for both substances. PAF-acether, when added to a spiral cut guinea-pig trachea suspended in a tissue bath containing Krebs-Henseleit buffer, produced a dose-dependent loss of active tissue tension. The ED₅₀ for this effect of PAF-acether was 75 ng/ml. PAF-acether produced a maximal relaxation which was 68% of that produced by PGE₁ and the effect could not be modified by aspirin or propranolol pretreatment. 5-HT, alone, contracted the guinea-pig trachea strip in a dose-dependent manner, but caused relaxation instead when methysergide was present. Aspirin, phenoxybenzamine and propranolol did not alter this loss of active tissue tension. A similar observation was made in vivo using the guinea-pig bronchoconstriction model, in which PAF-acether as well as 5-HT given to methysergide-treated animals caused a decrease in intratracheal pressure. This action of PAF-acether may yield a suitable bioassay method which could facilitate routine measurements of the substance. Furthermore, the similarity in action of PAF-acether and of 5-HT on methysergide-treated animals leads one to speculate about the relationship between the two substances and their mechanism of action in smooth muscle.     

Regulation of atrial myocardial cellular volume during exposure to isosmotic high potassium or hyposmotic media

The density of atrial myocardial interstitial collagen and atrial cell volume regulation were studied under conditions in which cell membranes and ion pumps could not prevent swelling. Rat and guinea-pig atrial sections were incubated in modified Krebs-Henseleit solutions in which either potassium was substituted for sodium ion for ion, or sodium chloride was reduced. Atrial collagen was examined by scanning electron microscopy. Atrial water, ³H-inulin and ³H-mannitol spaces, potassium, sodium, chloride and protein contents, and resting transmembrane potentials were measured. Data were compared with ventricular myocardium and previously studied renal cortex. Atrial collagen was considerably sparser than ventricular collagen. Atrial swelling in potassium substituted media was three times greater than ventricular swelling, but only about half of renal cortical swelling. In dilute media, atrial swelling was greater than ventricular swelling, but, in contrast to renal cortex, atria failed to achieve osmotic equilibrium without substantial losses of ions in the most dilute medium. These findings suggest a significant role for myocardial collagen in limiting cell swelling when mechanisms which normally regulate cell volume are unable to prevent swelling.