动物造模,慢性阻塞性肺疾病实验动物模型 z-bio 2022-11-04 252

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

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

　　Cigarette smoke (cs): smoking is the most important risk factor of COPD and the most common inducer of COPD. 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 particulates (TSP) or total particulate matter (TPM), including nicotine and carbon monoxide. However, there is no standard animal exposure method or protocol, and the use of CS as an inducer of COPD in vivo is one of the limitations. The type of cigarettes used to produce smoke (commercial and research cigarettes, or with filters), the composition of CS used for exposure, the delivery system (whole body only with the nose), and most importantly, the amount of smoke given to animals is an important determinant. Despite these limitations, CS has been shown to induce many features of COPD animals, including pulmonary macrophage and neutrophil infiltration, airway fibrosis, and emphysema. This chapter describes the exposure of many 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 show different degrees of sensitivity to CS. In some studies, different exposure protocols were used. Mice were exposed once or twice/several days, several times/week/several weeks/one month in a smoking device as systemic 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 used rats because they could distinguish measurable emphysema. Many studies have shown that the occurrence of emphysema in mice is very different from that in rats. Chronic obstructive pulmonary disease (COPD) was induced by different exposure modes, durations and cigarette types in rats.

　　Guinea pig: Guinea pig is a suitable species commonly used in the study of chronic obstructive pulmonary disease. These animals have many advantages because their lungs are similar in anatomy and physiology to human beings. In addition, there are similarities between guinea pigs and humans in physiological processes, especially in the autonomous control of airways and responses to allergens. However, there are also some shortcomings, such as the lack of molecular tools, the need to test the pharmacological research of many compounds, and the cost of purchasing and raising animals. These studies show that guinea pigs exposed to active tobacco smoke will have chronic obstructive pulmonary disease and emphysema like lesions, and show physiological changes similar to COPD in guinea pigs exposed to smoke. For example, chronic obstructive pulmonary disease was induced in these animals, guinea pigs were exposed to 8-9 minutes, 5 cigarettes with or without filters/day, for 5 or 6 days, for 3 months.

　　Dogs: Dogs have been widely used as models of asthma and chronic obstructive pulmonary disease, because the pathology and pathophysiology of chronic bronchitis and emphysema in dogs exposed to cs are similar to those in humans. Dog models, similar to other COPD models, have been used to examine new treatments before human trials. In one study, dogs developed pulmonary fibrosis and emphysema after a short period of direct inhalation of cs.

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

　　Lipopolysaccharide (LPS): LPS perfusion can induce COPD in a short period of 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 induced exacerbation of acute COPD and was 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 is conducive to the development of the disease. Exposure of animal chorionic villi to LPS can lead to the pathological features of COPD, such as pulmonary inflammation, airway hyperresponsiveness (AHR) and changes in lung structure. LPS exposure twice a week for 12 weeks induced inflammatory response.

　　Mice: The investigation shows that lipopolysaccharide inhalation in mice can cause emphysematous changes, lasting for 4 weeks. In addition, it has been reported 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 perfusion using a mini spray fogger or nasal cavity.

　　Rats: In the rat model, LPS can be inhaled in the same way as mice, resulting in the pathological characteristics of COPD.

　　Elastase: Elastase is a proteolytic enzyme, which is released from activated neutrophils in the lung, leading to the rupture of alveolar tissue and emphysema. The elastase model was perfused with elastase (such as porcine trypsin elastase (PPE), human neutrophil elastase and papain), resulting in lung tissue injury and the development of emphysema. This model is used to induce inflammatory response to start and maintain the inflammatory response of patients with chronic obstructive pulmonary disease. The main advantage of elastase model is to induce disease through single perfusion of enzyme in the lung. Control the severity of disease by regulating the amount 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, thus increasing the number of clinical events. A variety of animals have been used in elastase induced emphysema model [to replicate some characteristics of the disease caused by human CS, such as inflammatory cell infiltration into the lung and systemic inflammatory response.

　　Mice: The animal model of chronic obstructive pulmonary disease (COPD) induced by elastase inhibitor was established by intranasal administration of porcine trypsin elastase 1.2 (U) 1 day/week for 4 consecutive weeks. In some studies, mice received 2 U/100 g/kg BW dissolved in 100 μ L Phosphate buffered normal saline solution of porcine trypsin elastase.

　　Rats: Emphysema model in rats was induced by intratracheal injection of a single dose of elastase (28 U/100 g/kg) and observed 7, 15, 30 and 365 days after injection. In other studies, rats received a single intratracheal dose of elastase. Borzone et al. showed that the respiratory mechanics of hamsters changed seriously after intratracheal instillation of the same dose for 4 months.

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

　　Other models: Other drugs have also been used to induce airway inflammatory damage. Apoptosis model focuses on the failure of self repair after COPD lung injury, and focuses on the normal operation of lung tissue. Apoptosis induced chronic obstructive pulmonary disease is related to inhibition of VEGF receptor. In addition, in recent years, a genetic modification model imitating COPD has been developed. These models can be used to identify the physiological functions of different genes and the possible mechanisms of COPD. For example, in gene targeted mice, emphysema and airspace expansion occur after exposure to cs.

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

　　Mice: The mouse model of chronic obstructive pulmonary disease (COPD) was observed to show chronic inflammation, increased infiltration of lung parenchyma cells, increased mucus secreting goblet cells, thickened airway epithelium, enlarged alveoli, and airway remodeling. In addition, airway remodeling, pulmonary inflammation, goblet cell proliferation and alveolar enlargement were observed in the mouse model of chronic obstructive pulmonary disease induced by PPE and LPS. In addition, significant increases in airway wall thickness and airspace size were observed after smoke exposure in mice.

　　Rats: COPD animal model showed that the bronchi and bronchioles were narrowed, the thickness of arterial wall and the size of alveolar increased. In CS group, pulmonary function indexes such as airway resistance, respiratory system resistance, tissue damping, tissue elasticity and respiratory system compliance increased. In addition, elastase treated rats showed mild space enlargement, alveolar space fragmentation and inflammation. The number of neutrophils in lung tissue, mucus secretion, edema and pulmonary inflammation were also increased in rats with chronic obstructive pulmonary disease.

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

　　In vivo measurement of TR: After inhalation of large doses of methacholine (MCH) aerosol, the TR in vivo is usually evaluated by whole-body plethysmography. Mice: AHR was evaluated in mice exposed to CS by methacholine challenge and whole-body plethysmography. 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 guinea pig model of chronic obstructive pulmonary disease to histamine accumulation concentration. Then, draw the cumulative concentration reaction curve and calculate the 50% effective concentration (EC50 h) of the maximum reaction caused by histamine. The concentration response curve of guinea pigs exposed to CS isoproterenol was constructed.

　　Inflammatory cells and mediators: total leukocyte count: various types of cells participate 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 destroy tissues and induce chronic inflammation.

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

　　Guinea pigs: The total number of white blood cells and eosinophils in the blood of guinea pigs with chronic obstructive pulmonary disease increased. Total leukocytes, eosinophils and neutrophils increased in lung lavage fluid of guinea pigs with chronic obstructive pulmonary disease. This paper summarized the total leukocyte count and leukocyte count of blood and lung lavage fluid in animal models of chronic obstructive pulmonary disease (COPD).

　　Macrophages secrete inflammatory mediators, such as interleukin-8 (IL-8) and 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 protease in the pathogenesis of COPD.

　　Mice: Increased secretion of BAL inflammatory cytokines, such as keratinocyte chemotactic factor (KC) and tumor necrosis factor, was observed in the CS induced COPD animal model- α、 Macrophage inflammatory proteins (MIP-2 and MCP-1 and MIP-1 α）。

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

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

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