甲醛诱导型哮喘大鼠模型的建立及其机理研究

发布时间：2018-06-19 23:38

本文选题：甲醛 + FA诱导型哮喘　；参考：《华中师范大学》2008年硕士论文

【摘要】： 随着人民生活水平的提高,室内装修已十分普遍,由此引起的装修型室内空气污染问题日益严重,甲醛(Formaldehyde,FA)是装修型室内空气污染的主要污染物之一。它具有污染时间长,来源范围广,污染水平高,生物毒性大等特点。室内气态FA的免疫毒性主要表现为免疫活性的增加,高浓度气态FA可以诱发过敏性鼻炎和支气管哮喘。特别是FA诱导型哮喘,发作严重时可以致人死亡,是室内装修型空气污染造成的最严重的健康危害之一。对于FA诱导型哮喘的发病机理,传统理论认为FA是一种过敏原,通过特异性IgE途径诱发哮喘,然而大量的流行病学调查在FA所致哮喘的患者体内并未检测到FA特异性IgE,提示我们FA可能有着不同于传统的致病机理。Mendell于2007年在《indoor air》上发表综述,认为FA诱导性哮喘的机理研究主要集中在两个方面,即FA对气道的直接刺激作用和间接免疫作用。一方面,不同的动物研究和人群研究结果表明,短期FA暴露即可引起受试者气道反应性的增加,表现为肺功能指数与空白组相比呈显著上升趋势。而另一方面,在相关动物实验和流行病学调查研究中,FA的暴露可增加过敏原诱导型哮喘发病几率及严重程度,显示出FA在过敏原诱导型哮喘发病过程中的易化作用。然而在大多数研究中,FA的这两种作用难以鉴别和区分。基于FA诱导型哮喘的相关机理研究,本实验旨在建立FA过敏原型哮喘大鼠职业模型,鉴别FA的两种作用,为进一步深入研究该疾病的分子机理奠定基础。实验结果如下: 1.FA诱导型职业哮喘大鼠模型的建立本研究采用SPF级Wistar大鼠,分别设立五个实验组:空白组、OVA致敏组、0.5 mg/m~3 FA+OVA组、3.0 mg/m~3 FA+OVA组和3.0 mg/m~3 FA单独作用组,建立FA职业暴露模型。即采用FA职业暴露标准,每天FA染毒6 h,染毒10 d,FA暴露期为各组实验大鼠进行卵清白蛋白(Ovalbumin,OVA)致敏前10天。OVA雾化激发7天后进行乙酰甲胆碱(O-Acetyl-β-methylcholine chloride,MCH)激发实验、肺泡灌洗液(Bronchoalveolar lavage fluid,BALF)细胞计数、肺组织石蜡切片苏木精伊红(Hematoxylin and eosin,HE)染色、肺组织白细胞介素-4(Interleukin-4,IL-4)及干扰素-γ(Interferon-γ,IFN-γ)酶联免疫反应(Enzyme-Linked Immuno Sorbent Assay,ELISA)检测实验。MCH激发实验及HE染色实验说明FA单独作用组及FA-OVA联合作用组均表现出了一种或几种典型的哮喘样症状,说明本研究成功建立了FA诱导型职业大鼠哮喘模型,为全面研究FA诱导型哮喘的分子机理奠定了坚实的基础。 2.FA直接作用和间接作用的鉴别本实验通过FA单独暴露模型和FA易化OVA哮喘大鼠模型的建立,对FA在FA诱导型哮喘发病过程中的直接作用和间接作用分别进行了研究。结果表明0.5和3.0 mg/m~3的气态FA暴露可显著增加OVA致敏大鼠的气道高反应性、气道结构变化程度,同时显著提高BALF中嗜酸粒细胞(Eosinophil,EOS)和白细胞总数以及肺组织中IL-4的表达水平,表明FA可能通过恶化EOS炎症和促进Th2类免疫反应而易化或恶化OVA诱导型哮喘。对于3.0 mg/m~3 FA单独作用组,一方面该组FA暴露可诱发实验大鼠持续的气道高反应性,伴随着肺组织中IFN-γ表达水平的极显著上升。另一方面该组实验大鼠气道结构、EOS计数均无显著变化,而EOS占白细胞总数比例及肺组织中IL-4水平较空白组相比显著下降,表明高浓度FA单独暴露可能通过激活Th1类免疫反应和非EOS炎症而诱发AHR等哮喘样症状。
[Abstract]:With the improvement of the living standard of the people, indoor decoration is very common, and the decoration type indoor air pollution is becoming more and more serious. Formaldehyde (Formaldehyde, FA) is one of the main pollutants in the decoration type indoor air pollution. It has the characteristics of long pollution time, wide source range, high pollution level, large biological toxicity and so on. Indoor gaseous FA The main immune toxicity is the increase of immune activity. High concentration of gaseous FA can induce allergic rhinitis and bronchial asthma. Especially, FA induced asthma can cause death when the attack is serious. It is one of the most serious health hazards caused by indoor air pollution. The traditional theory on the pathogenesis of FA induced asthma is the traditional theory. It is considered that FA is an allergens that induces asthma through a specific IgE pathway. However, a large number of epidemiological investigations have not detected FA specific IgE in patients with FA induced asthma, suggesting that FA may have different from the traditional pathogenicity mechanism,.Mendell in 2007, in , that the mechanism of FA induced asthma is considered. The study mainly focused on two aspects, the direct stimulation of the airway and the indirect immunization of the FA. On the one hand, the results of different animal studies and population studies showed that the short-term FA exposure could cause an increase in the airway responsiveness of the subjects, which showed a significant increase in the ratio of the pulmonary function index to the blank group. On the other hand, the related movement was related. In the experimental and epidemiological studies, FA exposure can increase the incidence and severity of allergen induced asthma, showing the susceptibility of FA in the pathogenesis of allergen induced asthma. However, in most studies, these two effects are difficult to identify and divide. Based on the mechanism of FA induced asthma, this is a study of the pathogenesis of asthma. The aim of the experiment was to establish the occupational model of FA allergic asthmatic rats, to identify the two effects of FA, and to lay the foundation for further study of the molecular mechanism of the disease. The experimental results are as follows:
Establishment of 1.FA induced model of occupational asthma in rats
In this study, SPF Wistar rats were used to establish five experimental groups: blank group, OVA sensitizing group, 0.5 mg/m~3 FA+OVA group, 3 mg/m~3 FA+OVA group and 3 mg/m~3 FA separate action group to establish a FA occupational exposure model. Valbumin, OVA) 10 days before.OVA atomization and excitation for 7 days, acetylmethacholine (O-Acetyl- beta -methylcholine chloride, MCH) excitation experiment, alveolar lavage fluid (Bronchoalveolar lavage fluid, BALF) cell count, lung tissue paraffin section hematoxylin eosin staining, lung tissue interleukin -4) and interferon gamma (Interferon- gamma, IFN- gamma) enzyme-linked immunosorbent assay (Enzyme-Linked Immuno Sorbent Assay, ELISA) test.MCH excitation experiment and HE staining experiment showed that FA individual action group and FA-OVA combined group showed one or several typical asthma like symptoms. The rat asthma model lays a solid foundation for the comprehensive study of the molecular mechanism of FA induced asthma.
Identification of direct and indirect effects of 2.FA
In this experiment, the direct and indirect effects of FA in the pathogenesis of FA induced asthma were studied by the FA exposure model and the model of FA susceptible OVA asthmatic rats. The results showed that the 0.5 and 3 mg/m~3 gaseous FA exposure could significantly increase the airway hyperresponsiveness and the degree of airway structure change in the OVA sensitized rats. A significant increase in the levels of Eosinophil, EOS, and the total number of leukocytes and the expression of IL-4 in the lung tissue in BALF indicates that FA may facilitate or exacerbate OVA induced asthma by worsening EOS inflammation and promoting Th2 immune responses. For 3 mg/m~3 FA alone, on the one hand, FA exposure can induce the continuous airway of experimental rats. Hyperresponsiveness was accompanied by a significant increase in the expression of IFN- gamma in lung tissue. On the other hand, there was no significant change in the airway structure and EOS count in the experimental rats, while the proportion of the total number of white cells and the level of IL-4 in the lung tissue were significantly lower than those in the blank group, indicating that the high concentration of FA may be activated by the activation of the Th1 immune response and not by the high concentration of FA. EOS inflammation induces asthma like symptoms such as AHR.
【学位授予单位】：华中师范大学
【学位级别】：硕士
【学位授予年份】：2008
【分类号】：R562.25;R-332

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