Name: generation of a chronic obstructive pulmonary disease model in mice by repeated ozone exposure
Uploaded: 2017-08-25T14:00:00
Description: Watch this Scientific Journal Video about Generation of a Chronic Obstructive Pulmonary Disease Model in Mice by Repeated Ozone Exposure at JoVE.com

The authors would like to express gratitude to Mr. Boyin Qin (Shanghai Public Health Clinical Center) for the technical assistance with the &#181;CT evaluation in this protocol.

NOTE: The OE model has been generated and used in previously reported research30,31,32. All animal experiments were approved by the Institutional Animal Care and Use Committee (IACUC) of Shanghai Jiaotong University.
1. Mice
<ol>
	<li>House pathogen-free, 7- to 9-week-old female BALB/c mice in individual ventilated cages in an animal facility under controlled temperature (20 &#176;C) and humidity (4...

In this study, we present a reliable method for generating a new COPD model. Compared to other models (i.e., LPS or PPE models), this OE model recapitulates the pathological process of COPD patients. Because cigarette smoke is the main hazardous material that causes COPD in human patients40, the CS model remains the most popular COPD model41,42. However, the CS model requires a 3- to 12-month R&#38;D period for new drugs. Compared...

It has been estimated that COPD, including emphysema and chronic bronchitis, might be the third leading cause of death in the world in 20201,2. The potential incidence of COPD in a population over 40 years old is estimated to be 12.7% in males and 8.3% in females within the next 40 years3. No medications are currently available to reverse the progressive deterioration in COPD patients4. Reliable animal models of COPD not only demand the imitation of the disease pathological process but also require a short generation period. Current COPD models, including the LPS or a PPE-induced model, can induce emphysema-like symptoms5,6. A single administration or a week-long challenge of LPS or PPE to mice or rats results in marked neutrophilia in the bronchoalveolar lavage fluid (BALF), increases pro-inflammatory mediators (e.g., TNF-&#945; and IL-1&#946;) in the BALF or serum, produces lung parenchymal destruction-enlarged air spaces, and limits airflow5,6,7,8,9,10. However, LPS or PPE are not causes of human COPD and thus do not mimic the pathological process11. A CS-induced model produced a persistent airflow limitation, lung parenchymal destruction, and reduced functional exercise capacity. However, a traditional CS protocol requires at least 3 months to generate a COPD model12,13,14,15. Thus, it is important to generate a new, more efficient animal model that meets the two requirements.
Recently, in addition to cigarette smoking, air pollution and occupational exposure have become more common causes of COPD16,17,18. Ozone, as one of the major pollutants (though not the major component of air pollution), can directly react with the respiratory tract and damage the lung tissue of both children and young adults19,20,21,22,23,24,25. Ozone, as well as other stimulators including LPS, PPE, and CS, are involved in a serious of biochemical pathways of pulmonary oxidative stress and DNA damage and are linked to the initiation and promotion of COPD26,27. Another factor is that the symptoms of some COPD patients deteriorate after being exposed to ozone, indicating that ozone can disrupt lung function18,28,29. Therefore, we generated a new COPD model by repeatedly exposing mice to high concentrations of ozone for 7 weeks; this resulted in airflow defects and lung parenchymal damage similar to those of previous investigations30,31,32. We extended the OE protocol to female mice in this study and successfully reproduced the emphysema observed in male mice in our previous studies30,31,32. Because COPD mortality has decreased in men but increased in women in many countries33, a COPD model in females is needed to study the mechanisms and to develop therapeutic methods for female COPD patients. The applicability of the OE model to all genders lends further support to its use as a COPD model.

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	<tbody>
		<tr height="42">
			<td height="42" style="width:211px;height:42px;">BALB/c mice</td>
			<td style="width:217px;">Slac Laboratory Animal,Shanghai, China</td>
			<td style="width:143px;">N/A</td>
			<td style="width:455px;">7-to-9-week-old female BALB/c mice were used in this study.</td>
		</tr>
		<tr height="42">
			<td height="42" style="width:211px;height:42px;">Individual ventilated cages</td>
			<td style="width:217px;">Suhang, Shanghai, China</td>
			<td style="width:143px;">Model Number: MU64S7</td>
			<td>The cages were used for housing mice in the animal facility.</td>
		</tr>
		<tr height="42">
			<td height="42" style="width:211px;height:42px;">Sealing perspex-box</td>
			<td style="width:217px;">Suhang, Shanghai, China</td>
			<td style="width:143px;">N/A</td>
			<td style="width:455px;">The box was used&#160; to contain the ozone generator. Mice were exposed to ozone within the box.</td>
		</tr>
		<tr height="42">
			<td height="42" style="width:211px;height:42px;">Electric generator</td>
			<td style="width:217px;">Sander Ozoniser, Uetze-Eltze, Germany</td>
			<td style="width:143px;">Model 500&#160;</td>
			<td>The device was used for generating ozone.</td>
		</tr>
		<tr height="42">
			<td height="42" style="width:211px;height:42px;">Ozone probe</td>
			<td style="width:217px;">ATi Technologies, Ashton-U-Lyne, Greater Manchester, UK</td>
			<td style="width:143px;">Ozone 300</td>
			<td>The device was used for monitoring and controlling the generation of ozone.</td>
		</tr>
		<tr height="42">
			<td height="42" style="width:211px;height:42px;">Pelltobarbitalum natricum</td>
			<td style="width:217px;">Sigma, St. Louis, MO, USA</td>
			<td style="width:143px;">P3761</td>
			<td style="width:455px;">Mice were anesthetized by intraperitoneal injection of pelltobarbitalum natricum.</td>
		</tr>
		<tr height="42">
			<td height="42" style="width:211px;height:42px;">Micro-Computed Tomography</td>
			<td style="width:217px;">GE Healthcare, London, ON, Canada</td>
			<td style="width:143px;">RS0800639-0075</td>
			<td>This device was used for acquiring images of the lung.</td>
		</tr>
		<tr height="42">
			<td height="42" style="width:211px;height:42px;">Micro-view 2.01 ABA software</td>
			<td style="width:217px;">GE Healthcare, London, ON, Canada</td>
			<td style="width:143px;">Micro-view 2.01&#160;</td>
			<td>This device was used for reconstruct the lung and analyze volume, LAA of the lung.</td>
		</tr>
		<tr height="42">
			<td height="42" style="width:211px;height:42px;">Treadmill machine&#160;</td>
			<td style="width:217px;">Duanshi, Hangzhou, Zhejiang, China</td>
			<td style="width:143px;">DSPT-208</td>
			<td>This machine was usd for fatigue test.</td>
		</tr>
		<tr height="38">
			<td height="38" style="width:211px;height:38px;">Body plethysmograph</td>
			<td style="width:217px;">eSpira&#8482; Forced Manoeuvres System, EMMS, Edinburgh, UK</td>
			<td style="width:143px;">Forced Manoeuvres System</td>
			<td height="80">This device was used to test spirometry pulmonary function.</td>
		</tr>
		<tr height="42">
			<td height="42" style="width:211px;height:42px;">Ventilator</td>
			<td style="width:217px;">eSpira&#8482; Forced Manoeuvres System, EMMS, Edinburgh, UK</td>
			<td style="width:143px;">Forced Manoeuvres System</td>
			<td height="80">This device was used to test spirometry pulmonary function.</td>
		</tr>
		<tr height="42">
			<td height="42" style="width:211px;height:42px;">Slide spinner centrifuge</td>
			<td style="width:217px;">Denville Scientific, Holliston, MA, USA</td>
			<td>C1183&#160;</td>
			<td>It was used to spin BALF cells onto slides.</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:211px;height:21px;">Wright Staining</td>
			<td style="width:217px;">Hanhong, Shanghai, China</td>
			<td style="width:143px;">RE04000054</td>
			<td>&#160;It was used to staining macrophages, neutrophils in the suspended BALF.</td>
		</tr>
		<tr height="42">
			<td height="42" style="width:211px;height:42px;">Hemocytometer</td>
			<td style="width:217px;">Hausser Scientific, Horsham, PA, USA</td>
			<td style="width:143px;">4000</td>
			<td>It was used to count cells.</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:211px;height:21px;">IL-1&#946;</td>
			<td style="width:217px;">Abcam, Cambridge, MA, USA</td>
			<td style="width:143px;">ab100704</td>
			<td height="63">They were used to test the respective factors in serum.</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:211px;height:21px;">IL-10</td>
			<td style="width:217px;">Abcam, Cambridge, MA, USA</td>
			<td style="width:143px;">ab46103</td>
			<td height="63">They were used to test the respective factors in serum.</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:211px;height:21px;">TNF-&#945;</td>
			<td style="width:217px;">Abcam, Cambridge, MA, USA</td>
			<td style="width:143px;">ab100747</td>
			<td height="63">They were used to test the respective factors in serum.</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:211px;height:21px;">Paraformaldehyde&#160;</td>
			<td style="width:217px;">Sigma, St. Louis, MO, USA</td>
			<td style="width:143px;">P6148</td>
			<td>The lung was inflated by 4% paraformaldehyde.</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:211px;height:21px;">Paraffin</td>
			<td style="width:217px;">Hualing, Shanghai, China</td>
			<td style="width:143px;">56#</td>
			<td>It was used to embed the lung.</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:211px;height:21px;">Rotary Microtome</td>
			<td style="width:217px;">Leica, Wetzlar,&#160; Hesse, Germany</td>
			<td style="width:143px;">RM2255</td>
			<td>It was used for sectioning the lung.</td>
		</tr>
		<tr height="42">
			<td height="42" style="width:211px;height:42px;">Hgaematoxylin and Eosin (H&#38;E) staining solution</td>
			<td style="width:217px;">Solarbio, Beijing, China</td>
			<td style="width:143px;">G1120</td>
			<td>H&#38;E staining was done for morphometric analysis.</td>
		</tr>
		<tr height="42">
			<td height="42" style="width:211px;height:42px;">Upright bright field microscope</td>
			<td style="width:217px;">Olympus, Center Valley, PA, USA</td>
			<td style="width:143px;">CX41</td>
			<td>It was used to image the H&#38;E staining slides.</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:211px;height:21px;">Adobe Photoshop 12</td>
			<td style="width:217px;">Adobe, San Jose, CA, USA</td>
			<td style="width:143px;">Adobe Photoshop 12</td>
			<td>It was used to count the number of alveoli on the H&#38;E stained images.</td>
		</tr>
		<tr height="42">
			<td height="42" style="width:211px;height:42px;">GraphPad prism 5</td>
			<td style="width:217px;">Graphpad Software Inc., San Diego, CA</td>
			<td style="width:143px;">GraphPad prism 5</td>
			<td>It was used for data analysis and production of figures.</td>
		</tr>
	</tbody>
</table>

generation of a chronic obstructive pulmonary disease model in mice by repeated ozone exposure

Chronic obstructive pulmonary disease (COPD) is characterized by persistent airflow limitation and lung parenchymal destruction. It has a very high incidence in aging populations. The current conventional therapies for COPD focus mainly on symptom-modifying drugs; thus, the development of new therapies is urgently needed. Qualified animal models of COPD could help to characterize the underlying mechanisms and can be used for new drug screening. Current COPD models, such as lipopolysaccharide (LPS) or the porcine pancreatic elastase (PPE)-induced emphysema model, generate COPD-like lesions in the lungs and airways but do not otherwise resemble the pathogenesis of human COPD. A cigarette smoke (CS)-induced model remains one of the most popular because it not only simulates COPD-like lesions in the respiratory system, but it is also based on one of the main hazardous materials that causes COPD in humans. However, the time-consuming and labor-intensive aspects of the CS-induced model dramatically limit its application in new drug screening. In this study, we successfully generated a new COPD model by exposing mice to high levels of ozone. This model demonstrated the following: 1) decreased forced expiratory volume 25, 50, and 75/forced vital capacity (FEV25/FVC, FEV50/FVC, and FEV75/FVC), indicating the deterioration of lung function; 2) enlarged lung alveoli, with lung parenchymal destruction; 3) reduced fatigue time and distance; and 4) increased inflammation. Taken together, these data demonstrate that the ozone exposure (OE) model is a reliable animal model that is similar to humans because ozone overexposure is one of the etiological factors of COPD. Additionally, it only took 6 - 8 weeks, based on our previous work, to create an OE model, whereas it requires 3 - 12 months to induce the cigarette smoke model, indicating that the OE model might be a good choice for COPD research.

Examples of 3D &#181;CT images of each group are displayed in Figure 1a. The ozone-exposed mice had a significantly larger total lung volume (Figure 1a and b) and LAA% (Figure 1c) than did the air-exposed control mice. The lung volume and LAA% remained elevated after six weeks of ozone exposure31,3...

Watch this Scientific Journal Video about Generation of a Chronic Obstructive Pulmonary Disease Model in Mice by Repeated Ozone Exposure at JoVE.com

Generation of a Chronic Obstructive Pulmonary Disease Model in Mice by Repeated Ozone Exposure

This study describes the successful generation of a new chronic obstructive pulmonary disease (COPD) animal model by repeatedly exposing mice to high concentrations of ozone.

Chronic obstructive pulmonary disease (COPD) is characterized by persistent airflow limitation and lung parenchymal destruction. It has a very high ...

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