Pseudomonas aeruginosa Induced Lung Injury Model

Summary

We have developed a mouse lung injury model by intra-tracheal injection of bacteria Pseudomonas aeruginosa. This model mimics lung injury during pneumonia and is clinically relevant.

Abstract

In order to study human acute lung injury and pneumonia, it is important to develop animal models to mimic various pathological features of this disease. Here we have developed a mouse lung injury model by intra-tracheal injection of bacteria Pseudomonas aeruginosa (P. aeruginosa or PA). Using this model, we were able to show lung inflammation at the early phase of injury. In addition, alveolar epithelial barrier leakiness was observed by analyzing bronchoalveolar lavage (BAL); and alveolar cell death was observed by Tunel assay using tissue prepared from injured lungs. At a later phase following injury, we observed cell proliferation required for the repair process. The injury was resolved 7 days from the initiation of P. aeruginosa injection. This model mimics the sequential course of lung inflammation, injury and repair during pneumonia. This clinically relevant animal model is suitable for studying pathology, mechanism of repair, following acute lung injury, and also can be used to test potential therapeutic agents for this disease.

Introduction

Lungs are exposed to environmental pathogens and are susceptible to inflammation and injury^1-3. During pathological conditions such as pneumonia or Adult Respiratory Distress Syndrome (ARDS), pathogens as well as inflammatory factors released by leukocytes induce injury and death of alveolar cells^1-3. It is important to develop animal models of acute lung injury to facilitate the study of pathology of injury as well as mechanism of repair.

Currently, most people use hyperoxia and bleomycin induced mouse lung injury models⁴. However, the mechanisms of hyperoxia caused injury are not the same as most common lu....

Protocol

The animal experiments were approved by the Animal Care Committee and Institutional Biosafety Committees of the University of Illinois at Chicago.

NOTE: All procedures involving pseudomonas should be performed with Biosafety Level 2 (BSL2) practices, which include but are not limited to: mask, eye protection, gown or jumpsuit, and double gloves. Work in certified Biosafety Cabinet. Treat instruments in contact with bacteria with bleach or chlorine dioxide based disinfectant. Use a sealed box for transport samples.

1. P. aeruginosa Culture and Growth

1. Store P. aeruginosa PA103 as a bac....

Results

Starting from 24 - 72 hr post P. aeruginosa injection, increased cellularity was observed in lung sections (Figure 1A-D). The lung started to recover from 96 hr post injury (Figure 1E). At 7 days post P. aeruginosa, normal alveoli morphology was largely restored (Figure 1F). Tunnel staining using lung sections prepared at 24 hr post P. aeruginosa showed cell death in alveoli cells (Figure 1G-I). In order to study the repair pro.......

Discussion

The Pseudomonas mouse lung injury model that we describe here mimics the whole process of inflammation, lung injury, repair, and resolution that occur following acute lung injury or pneumonia. It has unique advantages comparing with several other injury models in that it is clinically relevant and relatively safe and easy to handle.

The critical step in the procedure is that the injection of bacteria solution needs to be very slow. If injection is too fast, the mice are likely to die by choke........

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Anesthetic: Ketamin, xylazine, lidocaine, buprenorphine			pharmaceutical grade
27 G needle	Fisher	1482648
syringe	Fisher	14823434	1 ml
scissors	Fine Science tools
forceps	Fine Science tools
suture	Fisher	19-037-526
Eye gauge, glove, gown
Biosafety Cabinet
chlorine dioxide based disinfectant			Clidox
sheep blood agar plates	Medex supply	HL-1160