Experimental lung injury induced by trimellitic anhydride inhalation on guinea pigs.

Trimellitic anhydride (TMA) causes lung injury by inhalation exposure in humans. In order to investigate more precisely the mechanism of lung injury by TMA, an experimental animal model of TMA-induced lung injury was established. Guinea pigs were intramuscularly injected with trimellitylated bovine serum albumin (TM BSA) with complete Freund's adjuvant (CFA). Appreciable amounts of antibodies against TM epitopes were detected in the sera of these animals. Guinea pigs that were passively sensitized with anti-TM antisera as well as the actively immunized animals developed hemorrhagic pneumonitis after TMA inhalation. It is well recognized that hyperimmune antisera of guinea pigs contain two subclasses of IgG antibodies, IgG1 and IgG2, which are known as homocytotropic and heterocytotropic antibodies, respectively. To determine the role of these antibodies in the airway injury with alveolar hemorrhages, they were isolated by gel filtration and by ion exchange column chromatography, and the guinea pigs that were sensitized with each of these antibodies were exposed to TMA inhalation. The extent of lung injury in these animals was quantitatively determined by the measurements of lung extravasation of Evans blue dye injected intravenously after TMA inhalation. Significant increases in the extravasation of dye were observed in both animal groups sensitized with IgG1 and IgG2 antibodies. In addition, results obtained with heat-treated antisera and IgG1 antibody did not significantly differ from those obtained with untreated samples. These results suggest that the lung injury resulting from TMA inhalation exposure can be induced with humoral antibodies, not only IgG1 but also IgG2, and that at least two types of allergic reactions are involved in the pathogenesis of lung injury.     

Inflammatory responses in skin and airways after allergen challenge in brown Norway rats sensitized to trimellitic anhydride

Trimellitic anhydride (TMA) is a low-molecular-weight compound which causes occupational allergy. Brown Norway rats were sensitized to TMA injected intradermally (0.3% TMA suspended in oil). Three weeks later, we examined responses to either free TMA injected intradermally, or TMA conjugated to rat serum albumin (TMA-RSA) given by inhalation (0.5%, nebulized for 15 min). Twenty-one days after the sensitization, Evans blue dye was given i.v. (20 mg/kg), and extravasation of dye in skin was measured 30 min after oil or TMA injections (0.03–10% in oil). In a separate series of experiments, we evaluated the accumulation of eosinophils in the skin after single and repeated injections of TMA (0.03–0.3%). The injection sites were removed and fixed in formalin 18–24 h after the last injection. In a third series of experiments, we evaluated the effects of airway exposure to TMA-RSA (0.5% in 0.9% saline) on the accumulation of eosinophils in the bronchial wall counted with quantitative light microscopy. Intradermal injections of free TMA caused a dose-dependent increase of Evans blue dye extravasation which was significantly higher in sensitized animals than in controls. Skin histology revealed a significant and dose-dependent increase in eosinophils after repeated TMA injections in sensitized animals. Exposure to aerosolized TMA–RSA caused a significant increase of eosinophils in the bronchial wall of sensitized rats compared with nonsensitized rats. Sensitized animals showed significantly higher levels of specific IgG and IgE. We conclude that brown Norway rats can be used as a model of TMA-induced allergic inflammation, mimicking occupational asthma.     

Experimental silicosis: morphologic and biochemical abnormalities produced by intratracheal instillation of quartz into guinea pig lungs.

Six months after intratracheal instillation of silica, histologic, ultrastructural, cytologic, and biochemical studies were performed on the lungs of guinea pigs. The tissue response consisted of both diffuse alveolar septal infiltration with interstitial fibrosis and granulomatous infiltration with nodular fibrosis. Ultrastructural studies confirmed the presence of a mixed inflammatory exudate in the alveolar interstitium (histiocytes, neutrophils, eosinophils, and lymphocytes) and the Type II lining of cell hyperplasia. The number of lung cells recovered by lavage and the proportions of neutrophils and multinucleated cells in bronchoalveolar cells were significantly greater in experimental animals (P < .05) than in controls (intratracheal saline). Total lung collagen and collagen synthesis by cultured lung tissue were also increased in the experimental animals. Since the response of guinea pig lung to intratracheal silica included pathologic features common to human silicosis and idiopathic pulmonary fibrosis, this model has the potential for improving our understanding of both of these important clinical disorders.     

Eosinophil infiltration and enhancement of airway reactivity by leukocyte chemotactic factor, formyl-methionyl-leucyl-phenylalanine (fMLP), in guinea pigs.

N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP) is a bacterial-derived chemotactic factor for eosinophils and neutrophils. This study is aimed to examine whether or not eosinophil infiltration induced by intra-airway administration of fMLP causes the damage of the bronchial epithelium and results in airway hyperresponsiveness in normal non-sensitized guinea pigs. In normal guinea pigs fMLP administered by aerosol inhalation or intratracheal injection caused significant infiltration of eosinophils in the tracheal mucosa and enhanced bronchial reactivity to inhaled histamine 6 and 24 hours after exposure. Electron microscopic examination showed damage of the alignment of the epithelial cells in the bronchial mucosa in fMLP-treated guinea pigs. PAF antagonists CV3988 and WEB2086 and a 5-lipoxygenase inhibitor (AA-861) did not prevent fMLP induced eosinophil infiltration, which suggests that fMLP caused eosinophil infiltration mainly by its chemotactic activity, not by the release of platelet activating factor (PAF) or leukotrienes in this experimental condition. These results showed that in normal guinea pigs a bacteria-derived chemoattractant of fMLP could reproduce a sequence of eosinophil infiltration and airway hyperresponsiveness, similar to the inflammatory pathophysiology after antigen challenge in sensitized animals. We concluded that eosinophil infiltration induced by either immunological or non-immunological mechanisms can cause airway damage and airway hyperresponsiveness.     

Complement, membrane glycoproteins, and complement receptors: their role in regulation of the immune response

To determine the effect of complement on the normal antibody response we studied seven patients with genetically determined complement component deficiencies, guinea pigs deficient of C4 and C2, respectively, and two patients whose neutrophils and monocytes lack the C3bi receptor. Patients deficient of early complement components (C4, C2, C3) have abnormal antibody responses to the T-cell-dependent antigen, bacteriophage phi X 174. Complement-deficient guinea pigs (C4, C2) produce less antibody than normal guinea pigs and are unable to maintain measurable antibody levels; during secondary immunization they fail to develop amplification and to switch from IgM to IgG. This defect can be overcome by increasing the antigen dose or by injecting normal guinea pig serum at the time of the primary (but not the secondary) immunization. Patients with deficiency of the C3bi receptor were shown to have a significantly depressed antibody response to T-dependent antigens. We postulate that the contribution of complement to the mature humoral immune response is related to activation of C3. The initial production of IgM following antigen injection leads to antigen-antibody complexes which interact with complement, to be nonspecifically trapped by C3b and C3bi receptors on B cells or macrophages. Thus antigen is selectively accumulated within the lymphoid organs and in turn may entrap antigen-specific B cells by interaction of the trapped antigen with surface immunoglobulin. As a result, close approximation between antigen, antibody, and a network of specific and nonspecific lymphoid cells is initiated, allowing generation of specific memory cells and initiation of a prompt mature antibody response on subsequent exposure to antigen.     

Inhibition of aeroallergen-induced bronchial eosinophilia by azelastine in guinea pigs.

The ability of azelastine to influence allergic bronchial eosinophil infiltration in guinea pigs was studied. Aeroallergen challenge of actively sensitized guinea pigs produces eosinophil infiltration in bronchoalveolar lavage fluid collected 20-24 h after aeroallergen exposure. Azelastine and methylprednisolone, administered orally 2 h before challenge, inhibited eosinophilic infiltration yielding the ED50s of 1.55 and 4.48 mg/kg, respectively. WEB-2086, a platelet-activating factor antagonist (3 mg/kg), and theophylline, a phosphodiesterase inhibitor (30 mg/kg), also suppressed allergic bronchial infiltration of eosinophils by 44%. The data obtained in this study demonstrate that azelastine exerts direct bronchial anti-inflammatory activity in guinea pigs.     

卡介苗对豚鼠实验性哮喘的预防性治疗作用

目的:观察卡介苗(BCG)对哮喘豚鼠的预防治疗作用。方法:采用31只豚鼠,分为3组进行处理,分别为对照组、卵蛋白(OVA)致敏组和BCG处理组。用OVA(Ⅲ级)致敏豚鼠复制豚鼠哮喘模型。结果:本模型采用10%的OVA致敏,1%的OVA激发,所有动物都表现有不同程度的过敏反应症状。实验动物在接受BCG注射后,表现为以下特点:一是外周血淋巴细胞和单核细胞增加;二是BALF中细胞分类的变化,支气管肺泡灌洗液(BALF)中以淋巴细胞的增加最为明显。 经过OVA致敏的动物BALF和肺组织中嗜酸性粒细胞(EOS)明显增加,BCG不同程度地降低肺组织EOS的气道浸润及减轻OVA致敏豚鼠的气道反应。结论:[HTSS]使用本实验体系BCG可以减轻实验性哮喘的气道炎症反应。     

Allergic bronchial eosinophilia: a therapeutic approach for the selection of potential bronchial anti-inflammatory drugs

Aeroallergen-induced infiltration of eosinophils in the bronchoalveolar lavage fluid (BALF) in guinea pigs was used as a marker of bronchial inflammation. Drugs were administered orally 4 h after aeroallergen challenge. Allergic bronchial eosinophilia in guinea pigs was inhibited by orally administered dexamethasone and methylprednisolone. Terfenadine (a newer H₁-receptor antagonist), theophylline (a nonspecific phosphodiesterase inhibitor), and salbutamol (a β2-agonist) did not influence allergic eosinophilic infiltration. Many of these agents, administered prophylactically, have been reported to suppress allergic eosinophilic infiltration in the BALF of guinea pigs. Methylprednisolone, a steroid, inhibits allergic bronchial eosinophilia regardless of the time of administration; that is, 2 h before or 4 h after aeroallergen challenge. The therapeutic approach used in this study may facilitate drug discovery for bronchial inflammation/ asthma.     

Specific immunological and bronchopulmonary responses following intradermal sensitization to free trimellitic anhydride in guinea pigs

We have developed a guinea pig model of trimellitic anhydride-induced airway hypersensitivity responses. In one group of guinea pigs, injected intradermally with 0.1 ml 30% trimellitic anhydride (TMA), we examined the specificity of the bronchopulmonary response to TMA comparing the effect of intravenous TMA conjugated to guinea pig serum albumin (GPSA) with a control hapten (procion dye) protein conjugate (PD-GPSA). A significant increase in pulmonary inflation pressure (PIP) was provoked in sensitized animals following intravenous injection with TMA-GPSA (20%; 0-400, median; range) as compared to intravenous injection of PD-GPSA. In the second group we compared three different methods of sensitization: single injection of 0.1 ml of 0.3% TMA; four injections of 0.1 ml of 0.1% TMA; and a single high dose injection of 30% TMA. Following intravenous TMA-GPSA guinea pigs sensitized with a single injection 0.3% TMA had an increase in PIP of 395%; 220-600, while those given four repeat injections of 0.1% TMA had an increase in PIP of 343%; 315-490. These results were significantly higher than the increase in PIP (160%; 0-220) which occurred in guinea pigs sensitized with a single dose of 30% TMA. Four of 11 guinea pigs given low dose injections of TMA had bronchopulmonary responses to inhaled TMA-GPSA. All sensitized guinea pigs had specific IgG1 antibodies demonstrated by enzyme linked immunosorbent assay (ELISA) and confirmed by ELISA inhibition. Four guinea pigs sensitized by low dose injections of TMA had IgE antibodies demonstrated by passive cutaneous anaphylaxis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of xiao-qing-long-tang (XQLT) on bronchoconstriction and airway eosinophil infiltration in ovalbumin-sensitized guinea pigs: in vivo and in vitro studies

BACKGROUND: Xiao-qing-long-tang (XQLT sho-seiru-to), a traditional Chinese medicine, has been used to treat patients with bronchial asthma in Oriental countries for several centuries. However, the therapeutic mechanisms of this Chinese medicine remain a matter of considerable debate. Therefore, a series of experiments using ovalbumin-sensitized guinea pigs was performed to elucidate the possible antiasthmatic effect of XQLT. METHODS: The effect of XQLT on ovalbumin-induced airway inflammation in a guinea pig model of allergic asthma was examined, and early and late asthmatic responses were measured in terms of airway resistance and extent of eosinophil infiltration. Furthermore, the bronchorelaxing effect of XQLT was measured in isolated guinea pig trachea. RESULTS: XQLT significantly inhibited the antigen-induced immediate asthmatic response (IAR) and late asthmatic response (LAR) in actively sensitized guinea pigs. Cumulative administration of XQLT caused concentration-dependent relaxation of the carbachol-precontracted guinea pig trachea. The bronchorelaxing effect of XQLT was reversed by ICI-118551, a selective beta2-adrenoceptor antagonist. Furthermore, examination of bronchoalveolar lavage fluid (BALF) revealed that XQLT significantly suppressed the increase in eosinophils (24 h after antigen challenge) in the airway. In addition, XQLT significantly attenuated the increase in eosinophils at 1, 6, 24, 48, and 72 h after antigen challenge when it was administered once daily from the day of sensitization to the day of challenge. Histopathologic examination results showed that XQLT suppressed eosinophil infiltration into lung tissue. CONCLUSIONS: These results demonstrate that the antiasthmatic effects of XQLT appear to be partly mediated by stimulation of beta2-adrenoceptors, leading to bronchorelaxation, and that XQLT inhibits the infiltration of eosinophils into the airway. Thus, XQLT may be useful for the prevention or treatment of asthma.     

Role of eosinophils in the late asthmatic response

The occurrence of late asthmatic response (LAR) is effectively prevented by corticosteroids, but not all by beta-adrenergic drugs. LAR is considered to be of great clinical and therapeutic importance and to be involved in the progression of bronchial asthma into a severe or even an intractable form. However the exact mechanism of the occurrence of LAR remains obscure in many respects. LAR is believed to be due to type I allergy. In guinea pigs, a positive bronchial inhalation challenge following passive sensitization with allogeneic antibody does not induce LAR or eosinophilic infiltration of lung tissue. This experimental fact led us to surmise that LAR would seem likely to be elicited in passively sensitized animals if pronounced eosinophilic infiltration can be induced concurrently and to conduct an experiment with conjoined inhalation of platelet activating factor (PAF). PAF, which has a chemotactic activity for eosinophils, was administered to passively sensitized animals in attempt to examine a role of eosinophils in LAR. A goodly number of animals developed LAR on additional PAF inhalation. These animals, when compared with those without LAR, showed a significantly larger proportion of eosinophils in BALF (p less than 0.05) with an upward tendency for the proportion of neutrophils. Histologically, there was noted a striking association between LAR and eosinophilic infiltration of the bronchial submucosa. These results suggest that anti-IgE antibody is deeply involved in the elicitation of LAR, stressing the importance of eosinophilic infiltration.     

Immune-Mediated Migration of Neutrophils Into the Uterine Lumen of Guinea Pigs

ABSTRACT: Metritis was elicited by intrauterine infusion of tuberculin or killed Campylobacter fetus ssp. venerealis into vaccinated guinea pigs and lipopolysac-charide or immune complexes into normal animals. The local inflammatory response to intrauterine infusion of antigens, lipopolysaccharide, and immune complexes was determined by changes in differential cell counts in the uterine lavage fluid and by histopathological examination of uterine tissue. The percentage of neutrophils was significantly (p < 0.01) greater in uterine lavage fluid collected at 4 hr after infusion of tuberculin into animals vaccinated locally (intrauterine) with M. tuberculosis than in animals vaccinated parenterally (subcutaneously). In contrast, the local response to infusion with C. fetus ssp. venerealis was approximately the same in animals vaccinated intrauterine and subcutaneously with Campylobacter. The systemic response, measured by the delayed type hypersensitivity cutaneous reaction to intradermal injection of tuberculin, was significantly (p < 0.01) greater in animals vaccinated subcutaneously than intrauterine. Similarly, the concentration of Campylobacter antibody in the serum of animals vaccinated subcutaneously was significantly (p < 0.01) greater than in guinea pigs vaccinated intrauterine. The intrauterine infusion of immune complexes, composed of C. fetus ssp. venerealis and corresponding antibody, into the uterus of normal guinea pigs stimulated neutrophil migration into the uterine lumen. Infusion of lipopolysaccharide also stimulated neutrophil migration into the uterine lumen. A correlation between an increased percentage of neutrophils in uterine lavage fluid and infiltration of the uterine epithelium with neutrophils was observed.     

Establishment and characterization of a murine model for allergic asthma using allergen-specific IgE monoclonal antibody to study pathological roles of IgE

Allergen-specific IgE has long been regarded as a major molecular component of allergic asthma. Although IgE plays a central role in the early asthmatic response, its roles in the chronic phase, such as the late asthmatic response, airway hyperresponsiveness (AHR), and airway remodeling (goblet cell hyperplasia and subepithelial fibrosis) have not yet been defined well. In this study, we investigated the hypothesis that chronic responses could be induced by IgE-dependent mechanisms. BALB/c mice passively sensitized with an ovalbumin (OVA)-specific IgE monoclonal antibody (mAb) were repeatedly challenged with intratracheal administration of OVA. The first challenge induced early phase airway narrowing without any late response, but the fourth challenge caused not only an early but also a late phase response, AHR, and goblet cell hyperplasia. Macrophages, lymphocytes and neutrophils, but not eosinophils, were significantly increased in the lung 24 h after the fourth challenge. Interestingly, levels of OVA-specific IgG1 in serum increased by multiple antigen challenges. A C3a receptor antagonist inhibited the late asthmatic response, AHR, and infiltration by neutrophils. In contrast, no late response, goblet cell hyperplasia, inflammatory cells, or production of IgG1 was observed in severe combined immunodeficient mice. On the other hand, seven challenges in BALB/c mice induced subepithelial fibrosis associated with infiltration by eosinophils. In conclusion, the allergic asthmatic responses induced by passive sensitization with IgE mAb can provide a useful model system to study the pathological roles of IgE in acute and chronic phases of allergic asthma.     

Primary prevention of asthma: age and sex influence sensitivity to allergen-induced airway inflammation and contribute to asthma heterogeneity in Guinea pigs

BACKGROUND: Limiting allergen exposure in the sensitization phase has been proposed as a means of primary prevention of asthma, but its effectiveness is debated. HYPOTHESIS: Primary prevention of asthma is more effective in limiting asthma symptoms in young guinea pigs compared with adults, whether males or females. METHODS: The following experimental groups were used: young/young, sensitized and challenged before sexual maturity; young/adult, sensitized young and challenged after sexual maturity; adult/adult, sensitized and challenged after sexual maturity. Males and females were sensitized intraperitoneally with varying doses of ovalbumin (OVA) and challenged intratracheally with a constant OVA dose. Cellular infiltration into lung and lavage fluid as well as airway hyperresponsiveness to intravenous methacholine was determined 24 h later. RESULTS: In unsensitized animals, density of resident inflammatory cells as well as baseline pulmonary function differed with age and sex. Maximum OVA-induced eosinophilia in females occurred at a lower sensitizing dose of OVA than in males, and the slopes of the dose-response relationship differed significantly between sexes. Young females had more pronounced increases in eosinophils compared with some adult treatment groups. The concentrations of OVA-specific antibodies were not directly related to differences in cellular infiltration. Airway hyperresponsiveness to methacholine challenge was observed in all treatment groups. CONCLUSION: Young animals require major reductions in allergen exposure compared with adults to effectively limit airway inflammation in primary prevention. Heterogeneity of asthma symptoms seen with age and sex suggests that primary prevention by limiting allergen exposure or treatment with anti-inflammatory or bronchodilator drugs may be more effective strategies for specific age and gender populations.     

Eosinophilia

Isolated human basophils sensitized in vitro by IgE antibody, and challenged by antigen in the absence of complement, release a substance that attracts eosinophils but not neutrophils. The anaphylactic release of the eosinophilotropic substance is accompanied by morphological changes in the basophils and release of histamine and presumptive SRS-A. The anaphylactic eosinophilotropic substance differs from that formed in fresh serum by antigen-antibody complexes. Human IgG, aggregated chemically or with antigen, induces formation of anaphylatoxin and substances attracting both eosinophils and neutrophils. IgE, similarly aggregated, does not. Damaged basophils or neutrophils incubated in serum containing complement, confer on the serum activity attracting neutrophils and eosinophils. The suspensions of the three types of polymorphonuclear leucocytes used in these tests were 92-97% pure, prepared by the techniques of Day.     

Enhancement of antigen-induced bronchoconstriction in the guinea pig after intravascular complement activation with cobra venom factor

The purpose of the present studies was to begin to test the hypothesis that the complement system is important for antigen-induced bronchoconstriction in the guinea pig. The effect of the complement-depleting agent cobra venom factor (CVF) on antigen-induced bronchoconstriction in guinea pigs passively sensitized with IgG or IgE antibody to ovalbumin was determined. Intravenous injection of CVF significantly reduced total hemolytic complement activity (CH50), caused a transient decrease in dynamic lung compliance, an increase in pulmonary resistance, and a decrease in circulating white blood cells with a sustained decrease in platelets. Antigen-induced bronchoconstriction was not inhibited in either IgG- or IgE-sensitized guinea pigs depleted of complement. Thus, a role for the complement system as a contributing factor in antigen-induced bronchoconstriction was not supported. On the contrary, our studies revealed an enhanced antigen-induced bronchoconstriction in guinea pigs depleted of complement with CVF. Our studies were then directed towards characterizing the enhanced response to begin to determine the mechanism responsible. The enhanced antigen-induced bronchoconstriction occurred in both IgG- and IgE-sensitized guinea pigs and was most apparent at lower antigen doses. The enhanced response still occurred in animals treated for 5 min with a dose of CVF (10 U) which caused no demonstrable decrease in CH50, a 30% level of conversion of C3, and a normal response to C5a. These data suggested that the enhanced response was not related to the level of C5a responsiveness of the animal.(ABSTRACT TRUNCATED AT 250 WORDS)     

低压低氧治疗对哮喘豚鼠的影响

目的:探讨模拟高原防治哮喘的机理。方法:用卵蛋白致敏和诱发复制哮喘动物模型,分为哮喘发作组、缓解组和低压舱治疗组,并设立正常对照组进行以下检测:①放免法测定血浆及支气管灌洗液(BALF)中内皮素(ET)含量及血浆皮质醇水平;②肺组织切片光镜检查。结果:①光镜下哮喘发作组肺组织切片见嗜酸性粒细胞(EOS)浸润明显,缓解组浸润较少,治疗组明显减少;②血浆皮质醇水平发作组、缓解组分别明显高于和低于正常组,治疗组与正常组无明显差异;血浆ET含量哮喘缓解组明显高于其他3组,而BALF中ET含量则为发作组明显高于其他3组,后3组之间无明显差异。结论:低压低氧治疗后,哮喘豚鼠血浆及BALF中内皮素降低而血浆中皮质醇增高,肺组织嗜酸性粒细胞浸润减少,这可能是模拟高原环境防治哮喘的机理之一。     

抗TNF-α、IL-1β IgY抗体抗豚鼠过敏性支气管哮喘的实验研究

目的:探讨抗TNF-α、IL-1β IgY抗体治疗过敏性支气管哮喘的作用机制.方法:卵清白蛋白雾化吸入制备Hartley豚鼠过敏性支气管哮喘动物模型,随机分正常对照组(A组)、过敏性支气管哮喘模型组(B组)、0.1%抗TNF-α、IL-1β IgY(C组)和1.0%抗TNF-α、IL-1β IgY雾化吸入治疗组(D组).各组豚鼠治疗结束后2、4、8、24小时处死,肺组织切片H.E.染色;收集支气管肺泡灌洗液(BALF)Wright's染色计数炎症细胞.结果:①肺组织病理改变:B组各时间点可见肺泡管和肺泡壁结构受损,肺泡腔内充满渗出液、上皮细胞和白细胞,肺间质水肿、炎性细胞浸润、毛细血管扭曲或扩张淤血、有效血流的毛细血管显著减少.C组和D组肺泡管和肺泡壁结构受损轻于B组,肺泡腔内偶见少量炎症细胞,支气管腔及肺泡中的粘液栓较B组明显减少,支气管周围少见炎性细胞浸润,支气管粘膜上皮修复现象明显.②BALF细胞学变化:与B组相比,C和D组嗜酸性粒细胞、中性粒细胞、淋巴细胞数量显著下降(2、4、8小时,P均<0.05);巨噬细胞显著上升(2、4、8小时,P均<0.05).结论:抗TNF-α、IL-1β IgY抗体雾化吸入治疗豚鼠过敏性支气管哮喘能够显著减轻炎症病理反应.0.1%与1.0%的抗TNF-α、IL-1β IgY抗体疗效相当.     

Induction of lung eosinophilia and neutrophilia in guinea pigs following injection of Sephadex beads

We have developed a method of induction of airway eosinophilia and neutrophilia in guinea pigs by intravenous injection of various types of Sephadex beads. In the first series of experiments, we have shown that G-50 Sephadex beads (Superfine, 24 mg/kg in conscious animals) induced a large accumulation of inflammatory cells in alveolar walls. The bronchoalveolar lavage (BAL) fluid from animals treated with this dose of Sephadex beads contained about 85 × 10⁶ cells as compared to 20 × 10⁶ cells in control animals. The eosinophils corresponded to 41% of the BAL cell population as assessed with Wright-Giemsa staining. However, in the BAL fluid from these bead-treated animals, a significant increase of monocytes, lymphocytes, and neutrophils was also observed. We have also tested the potency of G-75, G-100, and G-200 Sephadex beads (Superfine) to induce eosinophilia in guinea pig. Nonlethal intravenous doses of G-75 (14.27 mg/kg), G-100 (8.0 mg/kg), and G-200 (10.71 mg/kg) Sephadex beads were selected and induced variable levels of airway eosinophilia and neutrophilia in conscious guinea pigs. The percentage of eosinophil recovered in the BAL fluid corresponded to 35, 61, and 44% of total cells for G-75, G-100, and G-200, respectively. The neutrophils corresponded to 24, 2, and 12% of the total BAL cells for G-75, G-100, and G-200, respectively. Since the size of the beads did not seem to correlate with the intensity of airway eosinophilia and neutrophilia, the effect of lower doses of the G-50 Sephadex beads (9.86–0.43 mg/kg) on the inflammatory cell infiltration was also tested. Results showed that there was a correlation between the neutrophil number and the number of beads (r=0.996), whereas the number of eosinophils was less directly correlated to the bead number (r=0.812). The alveolar eosinophils were purified from BAL fluid by centrifugation on a continuous Percoll gradient (65%) to separate eosinophils from neutrophils. Normodense eosinophils (density 1.087–1.100 g/ml) obtained from Sephadex-treated animals were found at the bottom of the continuous Percoll gradient (25 x 10⁶; 98% purity). These highly purified eosinophils released thromboxane A₂ (TxA₂) following stimulation with 2M ionophore A23187. The method of accumulation and purification of guinea pig alveolar eosinophils is simple, rapid, and provides a large number of pure normodense cells for further biological studies. The induction of airway eosinophilia and neutrophilia in guinea pigs following injection of various types of Sephadex beads could also provide an interesting model for the study of the mechanisms of eosinophilia and neutrophilia and their relationship to airway hyperresponsiveness.     

抑制肿瘤血管新生的复合肽VBP3局部刺激与全身过敏性实验

目的: 评价抑制肿瘤血管新生的复合肽VBP3的安全性。方法: 同体左右侧自身对比法对3 只家兔进行皮下注射的局部刺激实验。28 只豚鼠随机分为4组:无菌生理盐水(PS)阴性对照组6只,牛血清白蛋白(BSA)阳性对照组6只,复合肽VBP3 低剂量组6只,复合肽VBP3高剂量组6只,进行全身过敏实验;剩余4只豚鼠,牛血清白蛋白阳性对照组和复合肽VBP3 高剂量组各2只,不经致敏直接心脏激发。结果: 抑制肿瘤血管新生的复合肽VBP3 对家兔皮下注射的局部刺激反应轻微;豚鼠实验仅复合肽VBP3高剂量组1只豚鼠出现弱阳性过敏反应,且很快缓解,其余豚鼠未见过敏症状。结论: 抑制肿瘤血管新生的复合肽VBP3在本实验条件下安全。