Name: A Refined Aerosol-Based Intratracheal Bleomycin Delivery Method for Reproducible and Minimally Invasive Mouse Models of Pulmonary Fibrosis (Video) | JoVE Journal
Uploaded: 2026-01-16T12:30:00.000+00:00
Duration: 5 min 45 s
Description: Learn an aerosol-based intratracheal bleomycin delivery method for pulmonary fibrosis research in mice. This refined technique enables reproducible drug delivery with reduced surgical trauma for preclinical studies.

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5 minutes

This study was funded by the Peking Union Medical College 2024 Central University Education and Teaching Reform Special Funds Support Project (Project Title: OSF-Respiratory System; Project No.2024bkjg036), the Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences (2021-I2M-1-014), and the National Natural Science Foundation of China (81570077). The sponsors had no role in the study design, data collection and analysis, publication decision, or manuscript preparation.

All animal procedures were conducted under institutional guidelines approved by the Institutional Animal Care and Use Committee (IACUC). Proper animal welfare measures were implemented throughout the experiment. Male C57BL/6 mice aged 6-8 weeks, weighing approximately 25 g, were selected for the experiment. The Table of Materials lists all animals, reagents, and equipment used in this study and their commercial sources.
1. Animal selection and acclimation
<ol>
	<li>House all mice under specific pathogen-free conditions with a 12 h light/dark cycle and ad libitum access to food and water.</li>
	<li>Acclimate mice to the facility for 5-7 days before initiating the aerosol-based model.</li>
</ol>
2. Preparation of bleomycin solution
CAUTION: Bleomycin is a cytotoxic antitumor agent. Perform all steps in a certified biosafety cabinet while wearing appropriate PPE.
<ol>
	<li>Using a sterile 1 mL syringe, withdraw 3 mL of sterile 0.9% sodium chloride and inject it into a vial containing 15 U of bleomycin hydrochloride.</li>
	<li>Gently swirl the vial until the powder is fully dissolved to obtain a 5 U/mL stock solution.</li>
	<li>Aliquot the stock solution into sterile 1.5 mL microcentrifuge tubes. Prepare working solutions of 3.75 U/mL and 2.5 U/mL by diluting with sterile saline. 
	NOTE: For a 25 g mouse, these concentrations correspond to doses of 7.5 U/kg and 5 U/kg, respectively. Adjust concentrations if the mouse&#39;s weights vary.</li>
	<li>Store working solutions at 4 &#176;C for up to 1 week or at -80 &#176;C for up to 1 month. Thaw and bring to room temperature before use.</li>
</ol>
3. Aerosol-based intratracheal bleomycin delivery
<ol>
	<li>Anesthesia preparation and administration
	<ol>
		<li>Prepare the anesthetic working solution by dissolving 0.1 g of sodium pentobarbital powder in 10 mL of sterile physiological saline. Filter using a 0.22 &#956;m PES membrane filter. Store the solution at 4 &#176;C in a light-protected environment and use within 3 days of preparation.</li>
		<li>Administer sodium pentobarbital solution via intraperitoneal injection using a 1-mL syringe with a 26-gauge needle at a dose of 60 mg/kg body weight. If anesthesia depth or duration is insufficient, adjust the dose based on animal response under the guidance of the attending veterinarian.</li>
		<li>Assess anesthesia depth several minutes after injection by firmly pinching the toe and confirming the absence of withdrawal reflex before proceeding with subsequent procedures.</li>
	</ol>
	</li>
	<li>Preparation of aerosol delivery apparatus
	<ol>
		<li>Prepare the aerosol delivery apparatus, ensuring that the nebulizing needle, nebulizing syringe, and dosing pillar are all present and sterile (Figure 1B).</li>
		<li>Submerge the aerosol delivery syringe in sterile saline. Slowly aspirate the fluid and pause for 8 s. Expel the fluid rapidly. Repeat this three times to fill and flush the system.</li>
		<li>Refill the syringe with saline after the final expulsion. Attach the aerosolizing needle, ensuring the junction is filled with saline.</li>
		<li>Submerge the assembled needle in saline and repeat the aspirate-pause-expel cycle three more times to eliminate air bubbles. 
		NOTE: To confirm readiness, expel saline against a dark background. Ensure that the rapidly ejected saline forms a fan-shaped mist against a dark background.</li>
	</ol>
	</li>
	<li>Intratracheal aerosol delivery procedure
	<ol>
		<li>Prime the aerosol needle with bleomycin working solution by aspirating and expelling it thrice with 8 s pauses.</li>
		<li>Insert a 25 &#181;L dosing pillar on top of the 50 &#181;L pillar to calibrate volume. Aspirate the required volume (50 &#181;L). Expel any excess liquid. 
		NOTE: This dosing configuration ensures consistent delivery by minimizing human error.</li>
		<li>Place the anesthetized mouse on the intubation platform, hooking the upper incisors and taping the limbs to stabilize (Figure 1C). 
		NOTE: Confirm rhythmic chest movements. If the animal appears active, administer an additional anesthetic dose.</li>
		<li>Use curved forceps to pull out the tongue gently. Insert a small animal laryngoscope to expose the glottis (Figure 1D).</li>
		<li>Insert the aerosolizing needle vertically through the glottis. Deliver the bleomycin aerosol rapidly (Figure 1E). 
		NOTE: Angle the needle tip toward the desired lung for targeted delivery. Avoid inserting too deeply to prevent trauma. The tip of the nebulizer needle should be positioned close to but not touching the bifurcation point (first bifurcation) of the mouse&#39;s trachea to achieve the best modeling effect. If the tip is inserted only into the middle of the trachea, the aerosol may only strike the tracheal wall, forming large droplets that are coughed up or swallowed. If the tip is too close to the tracheal bifurcation, there is a risk of tracheal damage.</li>
	</ol>
	</li>
</ol>
4. Post-procedure recovery
<ol>
	<li>Place the mouse on a warming pad to maintain body temperature. Observe the mouse continuously until it recovers from anesthesia (typically 1-2 h).</li>
	<li>Perform a toe pinch to check reflexes and confirm the mouse is alive.</li>
	<li>Perform daily clinical monitoring for 21 days, including body weight, activity level, grooming, and respiratory signs.</li>
	<li>Euthanize animals when any of the following criteria are met: (i) &#62;20% loss of body weight compared with the pre-treatment baseline, or &#8805;15% loss accompanied by other clinical signs of distress; (ii) persistent severe respiratory distress at rest (labored or abdominal breathing, marked tachypnea or bradypnea, nasal flaring, or open-mouth breathing), with or without cyanosis of the extremities; (iii) inability to obtain food or water, marked lethargy, or a moribund appearance (no response to handling and/or loss of the righting reflex); or (iv) severe dehydration, hypothermia, or other signs of irreversible deterioration as judged by the attending veterinarian. When these humane endpoints are reached, euthanize the animals with an overdose of sodium pentobarbital (&#8805;150 mg/kg, i.p.), followed by a secondary physical method (e.g., cervical dislocation), to ensure death and minimize pain and distress.</li>
</ol>
5. Terminal lung function measurement and tissue collection
<ol>
	<li>On day 21, anesthetize the mouse with 90 mg/kg i.p. of the same anesthesia&#160;solution to induce deep anesthesia and suppress breathing.</li>
	<li>Confirm complete anesthesia via toe pinch. Expose the trachea by cutting the skin and separating the muscles.</li>
	<li>Make a small beveled incision in the trachea and insert the intubation needle. Secure with a surgical ligature.</li>
	<li>Transfer the mouse to the computer-controlled small animal lung mechanics ventilator. Initiate mechanical ventilation and ensure no spontaneous breathing. Use the ventilator system to measure pulmonary function parameters.</li>
	<li>Perform right ventricular perfusion with 5-10 mL of sterile saline until the lungs appear blanched.</li>
	<li>Dissect out the entire lung. Fix the left lung in neutral buffered formalin for 24 h.</li>
	<li>Embed the fixed lung tissue in paraffin, section it, and perform H&#38;E staining, Masson&#39;s trichrome staining, and immunohistochemical staining for COL1A1 and &#945;-SMA.</li>
	<li>Place the right lung in a 2 mL homogenization tube with beads. Add water per the hydroxyproline kit&#39;s protocol. Homogenize and proceed with the assay.</li>
</ol>

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<li>Moeller, A., Ask, K., Warburton, D., Gauldie, J., Kolb, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+bleomycin+animal+model%3A+a+useful+tool+to+investigate+treatment+options+for+idiopathic+pulmonary+fibrosis%5BTitle%5D)+AND+%22Int+J+Biochem+Cell+Biol%22%5BJournal%5D)">The bleomycin animal model: a useful tool to investigate treatment options for idiopathic pulmonary fibrosis.</a> Int J Biochem Cell Biol. 40 (3), 362-382 (2008).</li>
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<li>Barbayianni, I., Ninou, I., Tzouvelekis, A., Aidinis, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Bleomycin+revisited%3A+A+direct+comparison+of+the+intratracheal+micro-spraying+and+the+oropharyngeal+aspiration+routes+of+bleomycin+administration+in+mice%5BTitle%5D)+AND+%22Front.+Med.+%28Lausanne%29%22%5BJournal%5D)">Bleomycin revisited: A direct comparison of the intratracheal micro-spraying and the oropharyngeal aspiration routes of bleomycin administration in mice.</a> Front. Med. (Lausanne). 5, 269(2018).</li>
<li>Song, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((A+mouse+model+of+pulmonary+fibrosis+induced+by+nasal+bleomycin+nebulization%5BTitle%5D)+AND+%22J.+Vis.+Exp%22%5BJournal%5D)">A mouse model of pulmonary fibrosis induced by nasal bleomycin nebulization.</a> J. Vis. Exp. (191), e64097(2023).</li>
<li>Li, W., Hu, Y., Yuan, W., Li, L., Huang, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Comparison+of+two+mouse+models+of+lung+fibrosis+induced+by+intratracheal+instillation+and+intratracheal+aerosol+administration+of+bleomycin%5BTitle%5D)+AND+%22Nan+Fang+Yi+Ke+Da+Xue+Xue+Bao%22%5BJournal%5D)">Comparison of two mouse models of lung fibrosis induced by intratracheal instillation and intratracheal aerosol administration of bleomycin.</a> Nan Fang Yi Ke Da Xue Xue Bao. 32 (2), 221-225 (2012).</li>
<li>Meng, J., Peng, Z., Tao, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Murine+pulmonary+fibrosis+model+induced+by+repeated+low-dose+intravenous+injection+and+intratracheal+instillation+of+bleomycin%5BTitle%5D)+AND+%22Zhong+Nan+Da+Xue+Xue+Bao+Yi+Xue+Ban%22%5BJournal%5D)">Murine pulmonary fibrosis model induced by repeated low-dose intravenous injection and intratracheal instillation of bleomycin.</a> Zhong Nan Da Xue Xue Bao Yi Xue Ban. 38 (12), 1228-1232 (2013).</li>
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The authors have no conflicts of interest.

This study proposed an optimized noninvasive tracheal nebulization model of bleomycin-induced pulmonary fibrosis in mice. A small animal laryngoscope was used to locate the glottis, and a tiny nebulization needle was inserted into the mouse's airway. Pressure was manually applied to nebulize the medication into the lungs, thereby reducing the discomfort and suffocation associated with the retention needle used in noninvasive injection13,14. Additionally, these ae...

Pulmonary Fibrosis (PF) is a group of lethal diseases characterized by progressive lung parenchymal damage and abnormal repair, of which Idiopathic Pulmonary Fibrosis (IPF) accounts for 30%-40%, with the median age of diagnosis of patients being 65 years old, and more than 80% of them being 60 years old older than 60 years old1,2. As global aging intensifies, the incidence of IPF is increasing year by year, with a worldwide IPF incidence of 3-9/100,000/year, and according to a study in the United States of America in people over 65 years of age, the incidence in this population surged to 93.7/100,000/year3,4.
The first historically developed model of pulmonary fibrosis was the bleomycin-induced model, which is often used in academia, with the best characterization and most widely used animal model currently5, recapitulating many of the features of IPF and other fibrotic ILDs, including lung inflammation, epithelial injury, fibroblast proliferation, and excessive extracellular matrix (ECM) deposition6. In addition, both acute and chronic pulmonary fibrosis can be modeled depending on the dose and frequency of bleomycin administration. It has been reported that the lungs enter an acute inflammatory phase within 5-7 days after bleomycin exposure, followed by a fibrotic phase beginning around day 7. By day 21, pronounced fibrotic remodeling is typically observed, allowing the model to recapitulate both the early inflammatory response and the late-stage fibrotic pathology in a temporally defined manner7 (Figure 1A). This allows the study of the entire disease process from the initial injury to the fibrotic stage, which is very important for drug development and mechanism studies at all stages8,9.
Bleomycin modeling routes are diverse and can be delivered locally or systemically, including endotracheal, nasal, intravenous, and intraperitoneal routes. The most commonly used is an endotracheal injection. The disadvantage is that it creates incisions in the mice, which affects the survival rate of the modeled mice10. Improvements were later made to allow the use of an indwelling needle for tracheal intubation and drip injection in mice11. However, the drug pushed by the syringe can only be distributed in the lungs as a block, which can lead to uneven distribution of bleomycin in each lung lobe, producing local overdensity and affecting the stability of the mouse model. In addition, chamber nebulizer cartridges have been used for bleomycin delivery, but the amount of inhaled bleomycin aerosol in each mouse cannot be precisely quantified, and the single induction time is long12. Therefore, a refined aerosol-based intratracheal bleomycin delivery method is developed for reproducible and minimally invasive mouse models of pulmonary fibrosis. Bleomycin is aerosolized, enabling uniform dispersion and deposition in the lungs, thereby better recapitulating pulmonary disease pathology. It is hoped that the emergence of this method will accelerate research into drugs that can completely cure pulmonary fibrosis.

<table><tbody><tr><td>0.22 &amp;mu;m polyethersulfone syringe filter</td><td>Cytosci</td><td>CSTPE3320</td><td></td></tr><tr><td>1 mL disposable syringe</td><td>BD</td><td>300481</td><td></td></tr><tr><td>1.5 mL microcentrifuge tube</td><td>Servicebio</td><td>EP-150-M</td><td></td></tr><tr><td>2.0 mL reinforced lysis tube</td><td>Servicebio</td><td>HT-200-M</td><td></td></tr><tr><td>4 &amp;deg;C laboratory refrigerator</td><td>Meiling</td><td>BCD-402WPCX</td><td></td></tr><tr><td>50 mL conical centrifuge tube</td><td>Servicebio</td><td>EP-5001-J</td><td></td></tr><tr><td>-80 &amp;deg;C ultra-low temperature freezer</td><td>Haier Biomedical</td><td>DW-86L828J</td><td></td></tr><tr><td>Absolute ethanol</td><td>Sinopharm Chemical Reagent Co., Ltd</td><td>100092683</td><td></td></tr><tr><td>Acidic differentiation solution</td><td>Servicebio</td><td>G1039</td><td></td></tr><tr><td>Aerosol microsprayer for small animal intubation</td><td>Shanghai Yuyan Instruments Co., Ltd</td><td>Yan-30012</td><td></td></tr><tr><td>Basic surgical instrument set</td><td>Shanghai Yuyan Instruments Co., Ltd</td><td>YAN-21A3</td><td></td></tr><tr><td>Bleomycin hydrochloride solution</td><td>Hanhui Pharmaceutical Co., Ltd</td><td>H20055883</td><td></td></tr><tr><td>Bluing reagent</td><td>Servicebio</td><td>G1040</td><td></td></tr><tr><td>Computer-controlled small animal lung mechanics ventilator</td><td>EMKA Biotech Beijing Co.,Ltd.</td><td>FX-2</td><td></td></tr><tr><td>Electrical insulation tape</td><td>3M</td><td>1500</td><td></td></tr><tr><td>Eosin Y staining solution</td><td>Zhuhai Baso Biotech Co., Ltd</td><td>BA4022</td><td></td></tr><tr><td>Green marking ink</td><td>Pilot</td><td>Chiku-rin</td><td></td></tr><tr><td>Hematoxylin staining solution</td><td>Servicebio</td><td>G1004</td><td></td></tr><tr><td>Hydroxyproline quantification assay kit</td><td>Abcam</td><td>ab222941</td><td></td></tr><tr><td>Laminar flow hood</td><td>HDL</td><td>DL-CJ-1N</td><td></td></tr><tr><td>Laryngoscope for small animal procedures</td><td>Shenzhen Bilead Biology Technology CO., LTD</td><td>DXSHJ0</td><td></td></tr><tr><td>Light microscope</td><td>Nikon</td><td>E100</td><td></td></tr><tr><td>Low-toxicity dewaxing solution</td><td>Servicebio</td><td>G1128</td><td></td></tr><tr><td>Masson&#039;s trichrome staining kit</td><td>Zhuhai Baso Biotech Co., Ltd</td><td>BA4079B</td><td></td></tr><tr><td>Microplate reader with absorbance detection</td><td>Agilent</td><td>Synergy H1</td><td></td></tr><tr><td>Neutral buffered formalin</td><td>Servicebio</td><td>G1101-3ML</td><td></td></tr><tr><td>Neutral mounting medium</td><td>Sinopharm Chemical Reagent Co., Ltd</td><td>10004160</td><td></td></tr><tr><td>Recombinant Rabbit Monoclonal Anti-COL1A1 Antibody</td><td>Huabio</td><td>HA722517</td><td></td></tr><tr><td>Refrigerated centrifuge</td><td>Eppendorf</td><td>5424R</td><td></td></tr><tr><td>RNase-free water</td><td>Generalbiol</td><td>TYJC002</td><td></td></tr><tr><td>Small animal tracheal intubation platform</td><td>Shanghai Yuyan Instruments Co., Ltd</td><td>CG-02M</td><td></td></tr><tr><td>Sterile 0.9% sodium chloride solution</td><td>China Otsuka Pharmaceutical Co., Ltd</td><td>H12020024</td><td></td></tr><tr><td>Tissue homogenizer</td><td>Servicebio</td><td>KZ-III</td><td></td></tr><tr><td>Xylene</td><td>Sinopharm Chemical Reagent Co., Ltd</td><td>10023418</td><td></td></tr><tr><td>Zirconia grinding beads</td><td>Servicebio</td><td>G0203</td><td></td></tr></tbody></table>

a refined aerosol-based intratracheal bleomycin delivery method for reproducible and minimally invasive mouse models of pulmonary fibrosis

A Refined Aerosol-Based Intratracheal Bleomycin Delivery Method for Reproducible and Minimally Invasive Mouse Models of Pulmonary Fibrosis

Pulmonary fibrosis is characterized by progressive deposition of fibrotic scar tissue within the lung parenchyma, leading to severely impaired gas exchange. It underlies a spectrum of chronic interstitial lung diseases, notably idiopathic pulmonary fibrosis, a condition associated with an exceedingly poor prognosis. Given the lack of effective therapies, robust mouse models are critical for elucidating underlying pathological mechanisms and evaluating novel antifibrotic interventions. Bleomycin-induced pulmonary fibrosis remains the most extensively utilized experimental model. Common routes of administration in mice include intravenous and intraperitoneal injections, invasive open-tracheal instillation, and noninvasive tracheal dripping. However, invasive surgical methods often cause secondary tissue injury, potentially compromising model reproducibility and stability. Conversely, noninvasive tracheal dripping usually results in uneven bleomycin distribution across lung lobes and poses a risk of asphyxiation, thus reducing reproducibility and increasing technical challenges. To address these limitations, a refined aerosol-based intratracheal delivery method is developed that is operationally simpler, minimally invasive, highly reproducible, and ethically superior by significantly reducing animal distress. Using a small-animal laryngoscope to visualize the rima glottidis directly, a specialized aerosolizing needle is inserted into the trachea, markedly narrower than the mouse tracheal diameter. Bleomycin solution is delivered under precisely controlled pressure, generating a fine aerosol. This ensures uniform and efficient distribution of the agent throughout the lung parenchyma. Moreover, one can selectively target the left or right lung by directing the needle into the appropriate bronchus. This optimized model&#39;s dose-response relationship is extensively characterized by systematically monitoring changes in lung function, histopathological manifestations, and lung hydroxyproline content. This refined experimental protocol is anticipated to facilitate laboratory standardization, ultimately accelerating the development and preclinical validation of novel antifibrotic therapeutics.

In this study, we proposed an aerosol-based intrabronchial delivery method to induce pulmonary fibrosis in mice using bleomycin. In preliminary experiments, a green dye was aerosolized and administered to the lungs of different mice. The dye showed a speckled distribution pattern throughout the lungs, indicating that the aerosol-based intrabronchial administration allowed for uniform dispersion of the agent across all lung lobes (Figure 1F). The green ink delivery shown in <strong class="xfi...

Here, we present a protocol to model pulmonary fibrosis in mice using aerosolized bleomycin delivered via the trachea. This optimized method enables uniform, quantitative, and precise delivery without surgical incision, enhancing the reproducibility and reliability of bleomycin-induced fibrosis.

Pulmonary fibrosis is characterized by progressive deposition of fibrotic scar tissue within the lung parenchyma, leading to severely impaired gas ...

We aim to develop a reproducible, minimally invasive, aerosol-based, drug delivery model for inducing pulmonary fibrosis and improving preclinical drug evaluation. Our model enables consistent and reliable drug delivery while reducing surgical trauma and improving reproducibility across experiments. We plan to apply this model to test our unique therapy for pulmonary fibrosis and a clinical lung injury.To begin, using a sterile, one-milliliter syringe, withdraw three milliliters of sterile 0.9%sodium chloride, then inject sodium chloride into a vial containing 15 units of bleomycin hydrochloride. Gently swirl the vial until the bleomycin powder is fully dissolved to obtain a five-units-per-milliliter stock solution. Aliquot the stock solution into sterile, 1.5-milliliter micro centrifuge tubes.Then prepare working solutions of 3.75 units per milliliter and 2.5 units per milliliter by diluting the stock with sterile saline. Prepare the aerosol delivery apparatus ensuring the nebulizing needle, nebulizing syringe, and dosing pillar are all present. Submerge the aerosol delivery syringe in sterile saline.Slowly aspirate the fluid, pause for eight seconds, then rapidly expel the fluid. Then refill the syringe with sterile saline after the final expulsion. Attach the aerosolizing needle and ensure that the junction is filled with saline.Then submerge the fully assembled needle in sterile saline. To prime the aerosolizing needle with the bleomycin-working solution, aspirate and expel it three times with eight-second pauses between each cycle. Aspirate the bleomycin-working solution into the syringe.Insert a 25-microliter-dosing pillar on top of the 50-microliter pillar to calibrate the total volume. Expel any excess solution. Then place the anesthetized mouse on the intubation platform.Hook the upper incisors to the wire loop and tape the limbs to stabilize the mouse in position. Using curved forceps, gently pull out the tongue. Insert a small animal laryngoscope to visualize and expose the glottis.Then insert the aerosolizing needle vertically through the exposed glottis and deliver the bleomycin aerosol rapidly into the trachea. After that, place the mouse on a warming pad to maintain body temperature. Observe the mouse continuously until it fully recovers from anesthesia.Perform a toe pinch to check for reflexes and confirm that the mouse is alive. Hematoxylin and eosin staining revealed mild alveolar wall thickening and localized fibrosis in the five-units-per-kilogram bleomycin group. While the 7.5 units per kilogram group showed extensive alveolar collapse and severe fibrotic lesions.The Modified Ashcroft Score quantification demonstrated a dose-dependent increase in fibrosis severity in bleomycin-treated mice compared to saline controls. Masson's trichrome staining revealed increased collagen deposition in the five-units-per-kilogram group and extensive interstitial fibrosis in the 7.5 units per kilogram group. Quantification of collagen-positive areas confirmed a significant, dose-dependent increase in collagen deposition following bleomycin treatment.Immunohistochemical staining showed increased expression of Col1A1 protein in lungs of both bleomycin groups with stronger and broader staining observed in the 7.5-units-per-kilogram group. Hydroxyproline content was significantly higher in both bleomycin-treated groups confirming increased collagen accumulation in lung tissue. Static lung compliance was significantly reduced in a dose-dependent manner in the bleomycin-treated groups.Inspiratory capacity was significantly lower only in the 7.5-units-per-kilogram bleomycin group compared to saline. Respiratory system elastins increased significantly in the 7.5-units-per-kilogram group compared to saline. Respiratory system compliance was significantly decreased only in the 7.5-units-per-kilogram group.

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This video describes an intrabronchial approach to administer an experimental agent selectively into distal right and left lung. In the featured protocol, we will administer bleomycin intrabronchially into a mouse to obtain a better model for pulmonary fibrosis.

Intrabronchial Delivery: A Technique to Administer an Experimental Agent Selectively Into a Mouse Lung

This article presents a rapid and simple method for administering bleomycin directly into the mouse trachea via intubation. Key advantages of this method are that it is highly reproducible, easy to master, and does not require specialized equipment or lengthy recovery times.

An Improved Method for Rapid Intubation of the Trachea in Mice

We describe a non-invasive multimodal imaging approach based on Micro-CT and fluorescence molecular tomography for longitudinal assessment of the mouse lung fibrosis model induced by double intratracheal instillation of bleomycin.

A Multimodal Imaging Approach Based on Micro-CT and Fluorescence Molecular Tomography for Longitudinal Assessment of Bleomycin-Induced Lung Fibrosis in Mice

Here we present an effective method to investigate the antifibrotic activity of intravenously infused human mesenchymal stromal cells obtained from the whole umbilical cord following the induction of lung injury by an endotracheal injection of bleomycin in C57BL/6 mice. This protocol can be easily extended to the preclinical testing of other therapeutics.

Induction of Mouse Lung Injury by Endotracheal Injection of Bleomycin

Intratracheal (IT) administration of experimental agents in mice often results in asymmetric delivery to the distal lungs.  In this report, we describe a direct intrabronchial (IB) approach to cannulate each lung in living mice non-operatively.  This approach can be used to selectively administer agents to one lung or may be adapted to improve the symmetric agent delivery to both lungs.

Direct Intrabronchial Administration to Improve the Selective Agent Deposition Within the Mouse Lung

Various animal models of pulmonary fibrosis have been established using bleomycin to clarify the pathogenesis of pulmonary fibrosis and find new drug targets. However, most pulmonary fibrosis models targeting lung tissue have uneven drug administration. Here, we propose a model of uniform pulmonary fibrosis induced by nasal bleomycin nebulization.

A Mouse Model of Pulmonary Fibrosis Induced by Nasal Bleomycin Nebulization

This protocol describes the isolation of pulmonary interstitial macrophages (IMs) and their adoptive transfer after IL-33 stimulation of the lung alveoli in a mouse model, which can facilitate the in vivo study of idiopathic pulmonary fibrosis (IPF).

Adoptive Transfer of IL-33-Stimulated Macrophages into Bleomycin-Induced Mouse Models to Study Their Effect on Idiopathic Pulmonary Fibrosis In Vivo

Here, we present a protocol to utilize micro-computed tomography (micro-CT) to quantify ventilated regions in a unilateral bleomycin-induced pulmonary fibrosis model via intratracheal instillation on the lesional side.

Unilateral Lung Volume Analysis Using Micro-CT for Enhanced Assessment of Pulmonary Fibrosis in Preclinical Models

This protocol demonstrates the oropharyngeal aspiration technique for use in the bleomycin murine model of pulmonary fibrosis.

Oropharyngeal Administration of Bleomycin in the Murine Model of Pulmonary Fibrosis

Cell therapy offers a promising intervention for pulmonary fibrosis by using progenitor cells to repair damaged tissue and improve lung function. As imaging plays a pivotal role in tracking cell integration, herein, we describe magnetic particle imaging-guided in vivo tracking of cell therapy for pulmonary fibrosis in a mouse model.

Image-guided In Vivo Tracking of Transplanted Distal Lung Epithelial Progenitor Cells for Pulmonary Fibrosis Using Magnetic Particle Imaging

This protocol delineates a method for inducing pulmonary fibrosis in mice through repeated oropharyngeal administration of bleomycin, yielding pathological features closely resembling those of idiopathic pulmonary fibrosis.

Refined Murine Model of Idiopathic Pulmonary Fibrosis

Learn an aerosol-based intratracheal bleomycin delivery method for pulmonary fibrosis research in mice. This refined technique enables reproducible drug delivery with reduced surgical trauma for preclinical studies.

A Refined Aerosol-Based Intratracheal Bleomycin Delivery Method for Reproducible and Minimally Invasive Mouse Models of Pulmonary Fibrosis (Video) | JoVE Journal

A Refined Aerosol-Based Intratracheal Bleomycin Delivery Method for Reproducible and Minimally Invasive Mouse Models of Pulmonary Fibrosis

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