慢性阻塞性肺疾病,动物模型 z-bo 2020-12-06 911

　　Background: Chronic obstructive pulmonary disease (COPD) is the leading cause of morbidity and mortality worldwide. It is characterized by chronic airway inflammation, high mucus secretion, airway remodeling, and emphysema, resulting in reduced lung function and difficulty breathing. Chronic obstructive pulmonary disease develops slowly and slowly, occasionally triggered by inflammatory reactions caused by substances such as harmful gases, bacteria or viruses. There is no effective treatment method, because the pathogenesis of COPD is still poorly understood at the molecular level. The lack of effective small animal models is a major limiting factor for COPD research. However, animal experiments provide a way to continue the treatment of all chronic diseases including the respiratory tract and lungs. Animal models are used to study chronic obstructive pulmonary disease, study the inflammatory process, and determine the basic mechanism of COPD. Several animals have been used as models of chronic obstructive pulmonary disease, including rodents, dogs, guinea pigs, monkeys, and sheep, but the appropriate model highly depends on the purpose of the research. This article reviews different methods of inducing animal models, different animals and various methods of measuring parameters. Therefore, this study will help researchers choose appropriate methods to induce chronic obstructive pulmonary disease animal models, and measure information variables according to their research design.

　　 Inducers of chronic obstructive pulmonary disease animal models: There are many ways to imitate COPD in animal models. These methods include exposing laboratory animals to CS (the main cause of COD), inflammatory stimuli (such as LPS), proteolytic enzymes (such as elastase), and genetic modification. In this section, we reviewed the application of different COPD inducers in various animals.

　　 Cigarette smoke (cs): Smoking is the most important risk factor for COPD and the most common COPD inducer. Environmental cigarette smoke may also cause respiratory symptoms and chronic obstructive pulmonary disease. Standardized research-grade cigarettes can easily provide a specific dose of total suspended particles (TSP) or total particulate matter (TPM), including nicotine and carbon monoxide. However, there is currently no standard animal exposure method or protocol, and one of the limitations of using CS as a COPD inducer in vivo. The type of cigarettes used to produce smoke (commercial cigarettes and research cigarettes, or with filters), the composition of the CS used for exposure, the delivery system (the whole body only with the nose), and most importantly, the smoke dose to the animal is important The determinant of. Despite these limitations, CS has been shown to induce many characteristics of COPD animals, including infiltration of macrophages and neutrophils in the lungs, airway fibrosis, and emphysema. This chapter describes the exposure of various animal species to tobacco smoke to simulate chronic obstructive pulmonary disease.

　　 mice: These are the most common animals exposed to cs, used to induce chronic obstructive pulmonary disease animal models. In terms of immune mechanism, mice are the best choice for COPD animal models. In addition, the mouse genome has been sequenced and has shown a similar human genome. In addition, the possibility of manipulating gene expression is suggested. However, several studies have shown that different strains of mice exhibit different degrees of sensitivity to CS. In some studies, different exposure regimens were used. The mice were exposed to a smoking device once or twice/a few days, several times/weeks/several weeks/months, as a whole body exposure or only in the nose.

　　 Rats: Rats are also used as animal models of chronic obstructive pulmonary disease, but they are considered a bad model because these animals seem to be resistant to the development of COPD. Some studies use rats because they can distinguish measurable emphysema. A number of studies have shown that the occurrence of emphysema in mice is very different from that in rats. Different exposure modes, durations and cigarette types induce chronic obstructive pulmonary disease in rats.

　　 Guinea pig: Guinea pig is a suitable species commonly used in chronic obstructive pulmonary disease research. These animals have many advantages because the anatomy and physiology of their lungs are similar to humans. In addition, there are similarities between guinea pigs and humans in their physiological processes, especially the autonomous control of the airway and the reaction to allergens. However, there are some disadvantages, such as the lack of molecular tools, the need to test many compounds for pharmacological studies, and the cost of buying and raising animals. These studies show that guinea pigs exposed to active tobacco smoke develop chronic obstructive pulmonary disease and emphysema-like lesions, and smoke-exposed guinea pigs show physiological changes similar to COPD. For example, to induce chronic obstructive pulmonary disease in these animals, guinea pigs are exposed to 8-9 minutes, 5 cigarettes with or without filter per day, for 5 or 6 consecutive days, for 3 consecutive months.

　　 Dog: Dogs have been widely used as a model of asthma and chronic obstructive pulmonary disease, because the pathology and pathophysiology of chronic bronchitis and emphysema in dogs after exposure to cs is similar to that of humans. The canine model, similar to other chronic obstructive pulmonary disease models, has been used to examine new treatments before human trials. In one study, dogs developed pulmonary fibrosis and emphysema after inhaling cs directly for a short period of time.

　　Monkey: Another animal model suitable for studying the mechanisms of allergic airway disease and chronic obstructive pulmonary disease is non-human primates. The results showed that monkeys exposed to cs exhibited chronic respiratory bronchiolitis and other respiratory changes. Exposure to CS for 6 hours/day, 5 days/week, and a total suspended particle concentration of 1 mg/m3, monkeys can develop experimental chronic obstructive pulmonary disease.

　　 Lipopolysaccharide (LPS): LPS perfusion can induce COPD model in a short time, and has certain human characteristics. Among gram-negative bacteria, air pollution and organic dust, lipopolysaccharide (the main component of the cell wall of gram-negative bacteria) is a pollutant. LPS induces acute COPD exacerbation and is administered alone or in combination with CS. In addition, LPS may play an important role in bacterial infection in the acute exacerbation of chronic obstructive pulmonary disease, which contributes to the development of the disease. Exposure of animal chorion to LPS can lead to pathological features of COPD, such as lung inflammation and airway hyperresponsiveness (AHR), and changes in lung structure. LPS exposure twice a week induces an inflammatory response after 12 weeks.

　　 Mice: Investigations show that inhalation of lipopolysaccharide in mice can cause emphysema-like changes for 4 weeks. In addition, there are reports in the literature that LPS can induce pathophysiological changes in chronic obstructive pulmonary disease (COPD), such as airway hyperresponsiveness and airway inflammation. In these studies, LPS was administered by intrapulmonary infusion using a micro-nebulizer fog machine or nasal cavity.

　　 Rat: In the rat model, LPS can be inhaled in the same way as mice, leading to the pathological features of COPD.

　　 Elastase: Elastase is a proteolytic enzyme that is released by activated neutrophils in the lung, causing the rupture of alveolar tissue and emphysema. The elastase model is perfused with elastase (such as porcine pancreatic elastase (PPE), human neutrophil elastase and papain), which leads to lung tissue damage and the development of emphysema. This model is used to induce an inflammatory response to initiate and maintain the inflammatory response in patients with chronic obstructive pulmonary disease. The main advantage of the elastase model is to induce disease through a single perfusion of enzyme in the lungs. Control the severity of the disease by adjusting the number of enzymes. However, the disadvantage of the elastase model is that the role of elastase in COPD emphysema depends on a variety of pathophysiological mechanisms, which increases the number of clinical events. A variety of animals have been used in elastase emphysema models [to replicate some of the characteristics of the disease caused by human CS, such as infiltration of inflammatory cells into the lungs and systemic inflammation.

　　 Mice: Porcine pancreatin elastase 1.2 (U) was administered to the nasal cavity for 4 consecutive weeks for 4 consecutive weeks to make an elastase inhibitor chronic obstructive pulmonary disease mouse model. In some studies, mice received 2 U/100 g/kg BW in the trachea of porcine pancreatic elastase dissolved in 100 μL of phosphate buffered saline solution.

　　 Rat: The rat emphysema model was injected with a single dose of intratracheal elastase (28 U/100 g/kg) and observed 7, 15, 30, and 365 days after the injection. In other studies, rats received a single dose of elastase in the trachea. The results of Borzone et al. showed that after 4 months of intratracheal instillation of the same dose, the respiratory mechanics of hamsters had serious changes.

　　 Combined induction: Animal models that mimic different aspects of COPD inflammation can be developed by using different inducers, such as CS, LPS, and PPE at the same time. For example, PPE and LPS can be used to induce chronic obstructive pulmonary disease lung inflammation in mice by nasal drip for 4 weeks. In another study, it was observed that the inflammatory response in rats was increased after the combined exposure of LPS and cs. In this model, rats are exposed to CS for 30 minutes, twice a day for 2 days. On day 3, animals were exposed to LPS for 30 minutes and 5 hours later to CS.

　　Other models: Other drugs have also been used to induce airway inflammatory damage. The apoptosis model focuses on the failure of self-repair after COPD lung injury, and the normal operation of lung tissue is the focus of research. Apoptosis-induced chronic obstructive pulmonary disease is related to the inhibition of VEGF receptors. In addition, genetic modification models that mimic COPD have been developed in recent years. These models can be used to identify the physiological functions of different genes and possible mechanisms of COPD. For example, in genetically targeted mice, emphysema and airspace enlargement occurred after exposure to cs.

　　 Measurement parameters: Pathological changes: The main feature of chronic obstructive pulmonary disease is airflow obstruction, most of which are irreversible. Airway obstruction may be the result of small airway stenosis, airway wall inflammation, and emphysema-related lung elastic shrinkage. Pulmonary structural changes such as emphysema and small airway remodeling are the pathological features of COPD. Small airway remodeling in chronic obstructive pulmonary disease occurs in secondary epithelial fibrosis, mucous cell proliferation, and sometimes increased airway smooth muscle (ASM) quality. In addition, inflammatory cells such as macrophages and neutrophils continue to infiltrate.

　　 Mice: Observed chronic obstructive pulmonary disease (COPD) mouse models with chronic inflammation, increased lung parenchymal cell infiltration, increased mucus secretion goblet cells, thickened airway epithelium, enlarged alveoli, and airway remodeling. In addition, in mouse models of chronic obstructive pulmonary disease induced by PPE and LPS, airway remodeling, lung inflammation, goblet cell hyperplasia, and alveolar enlargement were observed. In addition, after the mice were exposed to smoke, a significant increase in airway wall thickness and airspace size was observed.

　　 Rat: COPD animal model showed bronchial and bronchiolar stenosis, the thickness of arterial walls, and the size of alveoli increased. The lung function indexes of rats in the CS group, such as airway resistance, respiratory system resistance, tissue damping, tissue elasticity and respiratory system compliance increased. In addition, elastase-treated rats exhibited mild airspace enlargement, alveolar space fragmentation, and inflammation. Chronic obstructive pulmonary disease rats can also see increased neutrophil count, mucus secretion, edema and lung inflammation in the lung tissue.

　　 Tracheal responsiveness (TR): Airway hyperresponsiveness (AHR) is the main feature of asthma and chronic obstructive pulmonary disease. In addition, tracheal responsiveness (TR) to different stimuli is not only present in asthmatic animals, but also observed in animals exposed to CS. This parameter has been evaluated in some COPD animal models in vivo or in vitro.

　　 TR in vivo measurement: After inhaling a large dose of methacholine (MCH) aerosol, a whole body plethysmograph is usually used to assess TR in vivo. Mice: Mice exposed to CS using methacholine challenge and whole body plethysmography were used to assess AHR. The main indicator of airway obstruction, as a measure of Penh, shows a strong correlation with airway resistance.

　　 In vitro measurement of TR: To measure the tracheal muscle response of a guinea pig model of chronic obstructive pulmonary disease to the cumulative concentration of histamine. Then, draw a cumulative concentration-response curve and calculate the 50% effective concentration (EC50 h) at which histamine causes the maximum response. Construct a concentration response curve of guinea pigs exposed to CS isoproterenol. Inflammatory cells and mediators: total white blood cell count: various types of cells are involved in the pathophysiological mechanism of COPD including neutrophils, macrophages and eosinophils. CD8-T lymphocytes may play a major role in the acute exacerbation of COPD . They release some inflammatory mediators and tissue degrading enzymes, which can damage tissues and induce chronic inflammation.

　　 Mice: The total number of cells, macrophages and lymphocytes (especially CD8 + T cells) and neutrophils in the bronchoalveolar lavage fluid (BAL) samples of chronic obstructive pulmonary disease mice increased. The total number of inflammatory cells in the BAL animal model of chronic obstructive pulmonary disease increased, which was mainly due to the increase in the counts of macrophages and neutrophils. Rats: The total inflammatory cells and neutrophils in the alveolar lavage fluid of rats with chronic obstructive pulmonary disease increased, and the total white blood cells, macrophages, neutrophils and lymphocytes in the rat alveolar lavage fluid after smoking increased .

　　 Guinea pig: The total number of white blood cells and eosinophil count in the blood of a guinea pig model of chronic obstructive pulmonary disease increased. The total leukocytes, eosinophils and neutrophils in the lung lavage fluid of guinea pigs with chronic obstructive pulmonary disease increased. This article summarizes the total number of white blood cells and white blood cell counts in the blood and lung lavage fluid of chronic obstructive pulmonary disease (COPD) animal models. Macrophages secrete inflammatory mediators, such as interleukin 8 (IL-8), tumor necrosis factor-α (TNF-α), leukotriene B4 (LTB4), reactive oxygen species (ROS), monocyte chemoattractant protein 1 (MCP-1) and elastases such as matrix metalloproteinases (MMP-2, MMP-9, MMP-12), and cathepsin K, L. In addition, neutrophils significantly contribute to the secretion of serine proteases in the pathogenesis of COPD. Mice: Increased secretion of BAL inflammatory cytokines, such as keratinocyte chemokine (KC), tumor necrosis factor-α, and macrophage inflammatory proteins (MIP-2 and MCP-) were observed in the CS-induced COPD animal model. 1 and MIP-1α).

　　 Rats: The levels of TNFα, IL-8 and IL-10 in the serum and BAL of rats exposed to cs increased. The total protein level in the alveolar lavage fluid of the COPD rat model induced by the combination of CS and LPS also increased significantly. Another study showed that the levels of tumor necrosis factor-α and total protein in the alveolar lavage fluid of rats with chronic obstructive pulmonary disease (COPD) increased. After elastase treatment, the total protein content and some inflammatory cytokines such as IL-6, IL-1β and TNF-α also increased.

　　 Guinea pig: This article reports the increase of IL-8 and malondialdehyde (MDA) levels in the serum of guinea pigs of chronic obstructive pulmonary disease (COPD) model. The results of Feizpour et al. showed that the level of IL-8 in guinea pig serum and BAL of chronic obstructive pulmonary disease (COPD) model induced by CS increased.

　　Result: There are many ways to study animal chronic obstructive pulmonary disease. In order to develop a representative animal model of COPD, the induction method, evaluation parameters and characteristics of COPD should be evaluated. In this review, information about experimental models of chronic obstructive pulmonary disease induced in different animals, various methods, and different parameters that should be measured are provided. This basic information is valuable for future research on chronic obstructive pulmonary disease.