Name: measurement of the pressure-volume curve in mouse lungs
Uploaded: 2015-01-27T15:00:00.000+00:00
Duration: 9 min 49 s
Description: Watch this Scientific Journal Video about Measurement of the Pressure-volume Curve in Mouse Lungs at JoVE.com

This work has been supported by NIH HL-1034.

ジョンズ·ホプキンス大学動物実験委員会は、すべての動物プロトコールを承認した。 1.機器 PV曲線を測定する準備ができて設定複合システムは、 図1に示されている。 <ol><li>体積測定： <ol><li>ユーザが迅速に圧力限界に到達した後に、ポンプを逆転することができるスイッチでシリンジポンプを用いて、膨張および収縮の一定の割合を生成する。マウスのPV曲線の場合は、空気の3ミリリットルに設定された初期の体積（膨張前に）非常に軽く油を塗った5ミリリットルのガラス製の注射器を使用しています。 3mlのほぼすべてのマウスPV曲線のボリュームを測定するのに十分な大きさである。 </li><li>移動シリンジのプランジャーに接続された小型のセンサロッドと、ポンプハウジングに線形差動変圧器を取り付けることによって、ポンプによって送達される体積を測定する。 注：経験的な手段は、システム内のガス圧縮を補正するためにPVの立方で説明されているRVE記録部。 </li></ol></li><li>圧力測定： <ol><li> 0〜60センチメートルH 2 O（0-1 PSI）の範囲で標準の安価な圧力計を使用してください。 </li></ol></li><li>測定の記録： <ol><li> PV曲線を記録するには、XY機能（ 例えば、PowerLabの）を持つデジタルレコーダーを使用しています。 PV曲線をグラフ化するために、経肺圧力（PTP）を記録するために修正さ容積信号と他のチャンネルを記録するために、1つのチャネルを設定する。圧力を測定するためにメインをPowerlabに接続するブリッジプリアンプを使用してください。 0-40センチH 2 Oからの圧力チャンネルを校正し、0〜3ミリリットルボリュームチャネルを校正。 </li></ol></li></ol>ガス圧縮2.訂正注：このセットアップにおける重要な最初のステップで、圧力が増加するにつれて、ガス量が減少するため、マウスに送達される空気の体積は、SYRの変位よりもますます少なくなるのでインゲバレル。 <ol><li>肺に太陽光発電システムを接続するバルブを閉めるので、NOガスは、システムを残すことはできません。注入を開始し、レコーダーの補正されたボリューム·チャネルは、約40センチのH 2 Oに圧力が上昇するなどの任意の測定可能な変化を示しているかどうかを観察もしそうであれば、次のステップのように訂正します。 <ol><li>プランジャ変位測定（ すなわち、未補正体積）から膨張圧力に比例する項を減算することにより経験的にガス圧縮のための正しい。容積信号を表示するために（VCと呼ばれる）をPowerlabチャネルでこれを行い、マイナス係数倍の圧力。 </li><li>式の係数を決定します。まず、上の記録のグラフを回し、初期推定を行い、ポンプを起動します。インフレチューブは密閉されているので、Vcのチャネルは0-40センチH 2 Oからの圧力が上昇としてゼロを読み取るために、圧力係数乗算器を調整それがアップまたはダウンした場合、単にそれまでの補正係数を調整この圧力範囲にわたって平坦なままである。シリンジ内の容積を開始同じ3mlを変更されない場合には、この補正係数は、常に同じである。 </li></ol></li></ol>マウスの3.実験テスト<ol><li>マウスでのP-V曲線を測定するための手順。全ての動物プロトコルは、ジョンズホプキンス大学動物実験委員会によって承認された。 <ol><li>ケタミン（90ミリグラム/ kg）およびキシラジン（15ミリグラム/ kg）でマウス（生後6-12週でのC57BL / 6マウス）を麻酔し、反射運動の欠如によって麻酔を確認する。 注：PV曲線は10分未満で麻酔したマウスに完成し、端子手順であることができる。 </li><li> 18 Gスタブ針カニューレをマウスにTracheostomize。スタブ針を挿入することができる気管、小さなスリットを作った後、気管を覆う皮膚に小さな切開を作る気管を配置することによってこれを行います。糸で結びつけることによってカニューレを固定します。 </li><li>息1匹のマウスを許可する少なくとも4分間、00％の酸素。これは袋から、または名目上150呼吸/分で0.2ミリリットルの一回換気量で設定した人工呼吸器で自発呼吸を介し​​て行うことができる。 </li><li>気管カニューレを閉じて、マウス用の3-4分では、すべての酸素を吸収することができます。この酸素吸収手順は、動物の肺11のほぼ完全な脱ガスで死をもたらす。 ECG電極または直接観察とのハートビートの停止を測定することにより、マウスの死を確認してください。 </li><li>肺の脱気が完了し、肺容量がゼロになると、/分で3分の速度でシリンジポンプで室内空気との肺を膨張し始める。デジタルレコーダーの圧力トレースを監視し、それを35センチメートルH 2 Oに到達したときに、ポンプを逆転させる。 </li><li>圧力は気道がさらにボリューム低下を防止する肺胞の空気を閉じ込め、崩壊している時間によって負10cmのH 2 Oを、到達するまでデフレ曲線に従ってください。すぐにTリバース彼は肺が崩壊気道オープンとして再インフレートすることができ、再びポンプ。この不均一開口部は、この第二インフレの最初の部分で騒々しい見てインフレ肢によって通常は明らかである。 </li><li>圧力が再び35センチメートルのH 2 Oに到達すると、ポンプ方向を逆転し、この第二デフレ肢が0センチH 2 Oに到達するまで、肺を収縮していきその後、ポンプを停止する。 </li><li>圧力と流量とPV曲線のPowerLabのチャート記録を表示します。その後、別の肺病変を生じる肺実質における表現型の変化を検出するためにPV曲線を分析する。 </li></ol></li></ol>

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None of the authors have any financial interests that would be in conflict with the material presented in this paper.

本論文では簡単な再現性のある方法は、マウスにおける表現型肺の弾力性、総肺のPV曲線の古典的な方法を測定するために記載されている。このような曲線は、肺サーファクタントの発見と肺の安定性を提供する上で、その重要性に尽力しました。ここでは、PV曲線はまた、成体マウスの肺における肺の弾力性に関連するいくつかの変数を測定する手段を提供するのに有用であるかを示してい...

マウスは、現在の肺疾患の様々な主要な動物モデルである。肺気腫または線維症のモデルでは、本質的な表現型の変化は、最高の肺の弾力性の変化を測定することによって評価される。弾力性を測定するための多くの方法がありますが、古典的な方法は、全肺気量（TLC）に残存量（RV）から測定された全圧 - 容積（PV）曲線のことである。この測定は、ほぼ100年1-3さかのぼるほぼすべての哺乳動物種から大人の肺に行われている。このようなPV曲線はまた、胎児の肺の開発4-7の肺サーファクタントの機能の発見と理解に大きな役割を果たした。肺の表現型の測定などのPV曲線の重要性にもかかわらず、この測定を実行するには、全く標準化された方法がなかった。これは、膨張及び離散ステップと肺（各後の平衡可変待ち時間）を収縮させることにより、またはポンプを簡単に行われていること継続的に肺を膨らませると収縮することができます。 PV曲線は、多くの場合、ゼロといくつかのユーザ定義肺容量との容量範囲にわたって行われるが、異なる研究室により報告各圧力容量ループの持続時間は、時間2、数秒8で変化する、非常に可変であった。一部の研究者は、静的または準静的としてこの総肺のPV曲線を参照しますが、これらは少し洞察力を提供する定性的な用語であり、それらは、ここで使用されていません。また、PV曲線が広く、それが肺の構造変化の巨視的効果に関する有用な情報を提供することができるという事実にもかかわらず、マウスにおいて報告されていない。 いくつかの問題が含むPV曲線取得の変動をもたらした：インフレとデフレの1）速度; 2）インフレとデフレ圧力の脱線。 3）絶対的肺容量測定値を決定するための手段。ここで本方法では、3ミリリットルのレートは、/分コンプロミとして選ばれましたE、大規模なコホートを勉強場合は特に、測定は非現実的にするよう遅すぎて通常の換気に関連した動的な弾力性を反映しないように短すぎないという。 C57BL / 6健常マウスにおける公称全肺気量は1.2ミリリットル9のオーダーであるので、この速度は、通常、2つの完全にPVは約1.5分で実行するループを閉じを可能にする。 PV曲線が報告されている拡張された文献で ​​は、使用されるピークインフレ圧力は40以上のセンチH 2 Oに20程度の低いまで変化する、非常に可変されているこの変動の一部は、種に関連してもよいが、PV曲線のための圧力上限を設定する主な目的は、全肺気量（TLC）、または最大の肺容量の肺を膨らませることである。ヒトでのTLCは、個人が行うことができます最大の自主的な努力によって定義されているが、残念ながらこれは、任意の動物モデルで重複することはできません。このように、実験的なPV曲線における最大のボリュームが阻止される任意に研究者によって設定された最大圧力によって決定。目標は、PV曲線が平坦な圧力を設定することであるが、残念ながら、哺乳類の肺のPV曲線のインフレ手足は決して平坦である。だから、ほとんどの研究者はインフレ曲線が実質的に平坦化することから始まり、圧力、典型的には30センチH 2 Oを設定するマウスでは、しかし、PV曲線がインフレ四肢をダブルこぶでさらに複雑であり、このインフレ四肢が頻繁には30センチH 2 O 10で急激に上昇しているところなので、30こだわりのエンドポイントではありませんPVカーブ。このような理由から、私たちが調べた全ての株のインフレ手足が平らにし始める圧力であるマウスのPV曲線、圧力限界として35センチメートルのH 2 Oを使用します。 PV曲線自体は非常に非線形であるため、PVループの外観は、曲線の開始位置からのボリュームに依存するであろう。いくつかの商用人工呼吸器は、Fから始まる、ユーザーが大規模なPVループを行うことができRCが、FRC容積が未知の場合、これらの変更は、単に開始容量の変化から生じる可能性があるので、それは、任意の病状を有するこのようなP-V曲線の変化を解釈することは不可能ではなく、肺の構造の変化。したがって、絶対容量測定せず、PV曲線が解釈し、従ってほとんど有用性を有することはほとんど不可能である。 、肺容量を測定するいくつかの方法があるが、これらはしばしば厄介であり、特別な装置を必要とする。ここで説明する単純なアプローチでは、PV曲線は、生体内の脱気手順の後にゼロ音量で始まります。 要約すると、本論文では、マウスの肺における肺のPVカーブ測定を標準化する簡単な方法を実証し、肺の構造にリンクされているこの曲線から計算することができるいくつかの指標を定義します。 PV曲線は、このようにコムを有するマウスにおける表現型の構造変化を検出することができるでの直接適用を有する肺機能検査を提供そのような気腫および線維症などの肺の病理に。

<table><tbody><tr><td>Syringe pump</td><td>Harvard Apparatus</td><td>55-2226</td><td>Infuse/withdraw syringe pump</td></tr><tr><td>Pump 22 reversing switch</td><td>Harvard Apparatus</td><td>552217</td><td>Included with pump</td></tr><tr><td>Linear displacement transformer</td><td>Trans-Tek, Inc.</td><td>0244-0000</td><td></td></tr><tr><td>5 ml glass syringe</td><td>Becton Dickenson</td><td></td><td>Several other possible vendors</td></tr><tr><td>Digital recorder</td><td>ADInstruments</td><td>PL3504</td><td>Several other possible vendors</td></tr><tr><td>Bridge amp signal conditioner</td><td>ADInstruments</td><td>FE221</td><td></td></tr><tr><td>Gas tank, 100% oxygen</td><td>Airgas, Inc</td><td></td><td>Any supplier or hospital source will work</td></tr><tr><td>Pressure transducer: 0 - 1 psi&amp;nbsp;mV output</td><td>Omega Engineering</td><td>PX-137</td><td>Range &amp;asymp; 0 - 60 cm H&lt;sub&gt;2&lt;/sub&gt;O</td></tr></tbody></table>

measurement of the pressure-volume curve in mouse lungs

ここ数十年では、マウスは、肺疾患の様々な主要な動物モデルとなっています。肺気腫または線維症のモデルでは、本質的な表現型の変化は、最高の肺の弾性の変化を測定することによって評価される。最高のマウスにおけるそのような病理の根底にある特異的なメカニズムを理解するためには、現像病理を反映することができる機能的な測定を行うことが不可欠である。弾力性を測定するための多くの方法がありますが、古典的な方法は、肺容積の全範囲にわたって行われ、総肺の圧力 - 容積（PV）曲線のことである。この測定は、ほぼ100年さかのぼるほぼすべての哺乳動物種由来の成人の肺になされたものであり、そのようなPV曲線はまた、胎児の肺の開発における肺サーファクタントの機能の発見と理解に大きな役割を果たした。残念ながら、このような総PV曲線が広く、それらがmacroscに関する有用な情報を提供することができるという事実にもかかわらず、マウスにおいて報告されていない肺の構造変化のOPIC影響。肺容量でちょうど変化を測定する部分的なPV曲線が時々報告されていますが、絶対容積の測定値なしに、総PV曲線の非線形性の解釈は、これらの部分的なものは非常に困難にする。本研究では、我々は全体のPV曲線を測定するための標準化された方法について説明します。我々は、2つの一般的な肺の病状、気腫および線維症におけるマウス肺構造の変化を検出するために、これらの曲線の能力を試験した。結果は、これらの病理との期待の構造変化と一致して、いくつかの変数の有意な変化を示した。マウスにおける肺のPV曲線のこの測定は、このように時間的および治療的処置の潜在的効果以上の病態生理学的変化の進行をモニターするための簡単​​な手段を提供する。

PV曲線のための手順は、制御のみ健康なマウス用のビデオで実証されているが、我々は2つ​​の異なる一般的な病状、気腫および線維症を有するマウスにおける機能的および病理学的変化を検出するPV曲線の能力を調べた。これらの伝統的なモデルの詳細については、別の場所で12,13で説明。非常に簡単に、3％イソフルランで麻酔した後に肺気腫が気管に注入3または6 Uブタ膵臓エラ?...

Watch this Scientific Journal Video about Measurement of the Pressure-volume Curve in Mouse Lungs at JoVE.com

Measurement of the Pressure-volume Curve in Mouse Lungs

Here we present a protocol to simply and reliably measure the lung pressure-volume curve in mice, showing that it is sufficiently sensitive to detect phenotypic parenchymal changes in two common lung pathologies, pulmonary fibrosis and emphysema. This metric provides a means to quantify the lung&#8217;s structural changes with developing pathology.

マウス肺における圧力 - 容積曲線の測定

In recent decades the mouse has become the primary animal model of a variety of lung diseases. In models of emphysema or fibrosis, the essential ...

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18.5K ビュー.  Johns Hopkins University. Here we present a protocol to simply and reliably measure the lung pressure-volume curve in mice, showing that it is sufficiently sensitive to detect phenotypic parenchymal changes in two common lung pathologies, pulmonary fibrosis and emphysema. This metric provides a means to quantify the lung’s structural changes with developing pathology.

ビデオ: Measurement of the Pressure-volume Curve in Mouse Lungs

Pressure Controlled Ventilation to Induce Acute Lung Injury in Mice

Murine models are extensively used to investigate acute injuries of different organs systems (1-34). Acute lung injury (ALI), which occurs with prolonged mechanical ventilation, contributes to morbidity and mortality of critical illness, and studies on novel genetic or pharmacological targets are areas of intense investigation (1-3, 5, 8, 26, 30, 33-36). ALI is defined by the acute onset of the disease, which leads to non-cardiac pulmonary edema and subsequent impairment of pulmonary gas exchange (36). We have developed a murine model of ALI by using a pressure-controlled ventilation to induce ventilator-induced lung injury (2). For this purpose, C57BL/6 mice are anesthetized and a tracheotomy is performed followed by induction of ALI via mechanical ventilation. Mice are ventilated in a pressure-controlled setting with an inspiratory peak pressure of 45 mbar over 1 - 3 hours. As outcome parameters, pulmonary edema (wet-to-dry ratio), bronchoalveolar fluid albumin content, bronchoalveolar fluid and pulmonary tissue myeloperoxidase content and pulmonary gas exchange are assessed (2). Using this technique we could show that it sufficiently induces acute lung inflammation and can distinguish between different treatment groups or genotypes (1-3, 5). Therefore this technique may be helpful for researchers who pursue molecular mechanisms involved in ALI using a genetic approach in mice with gene-targeted deletion.

A murine model for ventilator induced lung injury is an important tool to study an acute lung injury in vivo. Here, we report an easy applicable in situ model for acute lung injury using high-pressure mechanical ventilation to induce acute failure of the lung.

マウスにおける急性肺障害を誘発するために圧力制御された換気

Murine models are extensively used to investigate acute injuries of different organs systems (1-34). Acute lung injury (ALI), which occurs with prolonged ...

医学

Right Ventricular Systolic Pressure Measurements in Combination with Harvest of Lung and Immune Tissue Samples in Mice

The function of the right heart is to pump blood through the lungs, thus linking right heart physiology and pulmonary vascular physiology. Inflammation is a common modifier of heart and lung function, by elaborating cellular infiltration, production of cytokines and growth factors, and by initiating remodeling processes 1.
Compared to the left ventricle, the right ventricle is a low-pressure pump that operates in a relatively narrow zone of pressure changes. Increased pulmonary artery pressures are associated with increased pressure in the lung vascular bed and pulmonary hypertension 2. Pulmonary hypertension is often associated with inflammatory lung diseases, for example chronic obstructive pulmonary disease, or autoimmune diseases 3. Because pulmonary hypertension confers a bad prognosis for quality of life and life expectancy, much research is directed towards understanding the mechanisms that might be targets for pharmaceutical intervention 4. The main challenge for the development of effective management tools for pulmonary hypertension remains the complexity of the simultaneous understanding of molecular and cellular changes in the right heart, the lungs and the immune system.
Here, we present a procedural workflow for the rapid and precise measurement of pressure changes in the right heart of mice and the simultaneous harvest of samples from heart, lungs and immune tissues. The method is based on the direct catheterization of the right ventricle via the jugular vein in close-chested mice, first developed in the late 1990s as surrogate measure of pressures in the pulmonary artery5-13. The organized team-approach facilitates a very rapid right heart catheterization technique. This makes it possible to perform the measurements in mice that spontaneously breathe room air. The organization of the work-flow in distinct work-areas reduces time delay and opens the possibility to simultaneously perform physiology experiments and harvest immune, heart and lung tissues.
The procedural workflow outlined here can be adapted for a wide variety of laboratory settings and study designs, from small, targeted experiments, to large drug screening assays. The simultaneous acquisition of cardiac physiology data that can be expanded to include echocardiography5,14-17 and harvest of heart, lung and immune tissues reduces the number of animals needed to obtain data that move the scientific knowledge basis forward. The procedural workflow presented here also provides an ideal basis for gaining knowledge of the networks that link immune, lung and heart function. The same principles outlined here can be adapted to study other or additional organs as needed.

A specific and rapid protocol to simultaneously investigate right heart function, lung inflammation, and the immune response is described as a learning tool. Video and figures describe physiology and microdissection techniques in an organized team-approach that is adaptable to be used for small to large sized studies.

肺およびマウスにおける免疫組織サンプルの収穫との組み合わせで右室収縮期圧測定

The function of the right heart is to pump blood through the lungs, thus linking right heart physiology and pulmonary vascular physiology. Inflammation is ...

免疫・感染学

A Standardized Method for Measuring Internal Lung Surface Area via Mouse Pneumonectomy and Prosthesis Implantation

Pulmonary morphology, physiology, and respiratory functions change in both physiological and pathological conditions. Internal lung surface area (ISA), representing the gas-exchange capacity of the lung, is a critical criterion to assess respiratory function. However, observer bias can significantly influence measured values for lung morphological parameters. The protocol that we describe here minimizes variations during measurements of two morphological parameters used for ISA calculation: internal lung volume (ILV) and mean linear intercept (MLI). Using ISA as a morphometric and functional parameter to determine the outcome of alveolar regeneration in both pneumonectomy (PNX) and prosthesis implantation mouse models, we found that the increased ISA following PNX treatment was significantly blocked by implantation of a prosthesis into the thoracic cavity1. The ability to accurately quantify ISA is not only expected to improve the reliability and reproducibility of lung function studies in injured-induced alveolar regeneration models, but also to promote mechanistic discoveries of multiple pulmonary diseases.

Internal lung surface area (ISA) is a critical criterion for assessing lung morphology and physiology in lung diseases and injury-induced alveolar regeneration. We describe here a standardized method that can minimize the measurement bias for ISA in both lung pneumonectomy and prosthesis implantation mouse models.

マウス肺切除術および義歯移植による内臓肺表面積の標準化法

Pulmonary morphology, physiology, and respiratory functions change in both physiological and pathological conditions. Internal lung surface area (ISA), ...

発生生物学

A Simple Method of Mouse Lung Intubation

A simple procedure to intubate mice for pulmonary function measurements would have several advantages in longitudinal studies with limited numbers or expensive animal. One of the reasons that this is not done more routinely is that it is relatively difficult, despite there being several published studies that describe ways to achieve it. In this paper we demonstrate a procedure that eliminates one of the major hurdles associated with this intubation, that of visualizing the trachea during the entire time of intubation. The approach uses a 0.5 mm fiberoptic light source that serves as an introducer to direct the intubation cannula into the mouse trachea. We show that it is possible to use this procedure to measure lung mechanics in individual mice over a time course of at least several weeks. The technique can be set up with relatively little expense and expertise, and it can be routinely accomplished with relatively little training. This should make it possible for any laboratory to routinely carry out this intubation, thereby allowing longitudinal studies in individual mice, thereby minimizing the number of mice needed and increasing the statistical power by using each mouse as its own control.

This paper describes a striaghforward and efficient method of intubating mice for pulmonary function measurements or pulmonary instillation, that allows the mice to recover and be studied at later times. The procedure involves an inexpensive fiberoptic light source that directly illuminates the trachea.

マウス肺挿管の簡単な方法

A  simple procedure to intubate mice for pulmonary function measurements would  have several advantages in longitudinal studies with limited numbers or  ...

Videomorphometric Analysis of Hypoxic Pulmonary Vasoconstriction of Intra-pulmonary Arteries Using Murine Precision Cut Lung Slices

Acute alveolar hypoxia causes pulmonary vasoconstriction (HPV) - also known as von Euler-Liljestrand mechanism - which serves to match lung perfusion to ventilation. Up to now, the underlying mechanisms are not fully understood. The major vascular segment contributing to HPV is the intra-acinar artery. This vessel section is responsible for the blood supply of an individual acinus, which is defined as the portion of lung distal to a terminal bronchiole. Intra-acinar arteries are mostly located in that part of the lung that cannot be selectively reached by a number of commonly used techniques such as measurement of the pulmonary artery pressure in isolated perfused lungs or force recordings from dissected proximal pulmonary artery segments1,2. The analysis of subpleural vessels by real-time confocal laser scanning luminescence microscopy is limited to vessels with up to 50 &#181;m in diameter3.
We provide a technique to study HPV of murine intra-pulmonary arteries in the range of 20-100 &#181;m inner diameters. It is based on the videomorphometric analysis of cross-sectioned arteries in precision cut lung slices (PCLS). This method allows the quantitative measurement of vasoreactivity of small intra-acinar arteries with inner diameter between 20-40 &#181;m which are located at gussets of alveolar septa next to alveolar ducts and of larger pre-acinar arteries with inner diameters between 40-100 &#181;m which run adjacent to bronchi and bronchioles. In contrast to real-time imaging of subpleural vessels in anesthetized and ventilated mice, videomorphometric analysis of PCLS occurs under conditions free of shear stress. In our experimental model both arterial segments exhibit a monophasic HPV when exposed to medium gassed with 1% O2 and the response fades after 30-40 min at hypoxia.

Hypoxic pulmonary vasoconstriction (HPV) is an important physiological phenomenon by which at alveolar hypoxia lung perfusion is matched to ventilation. The major vascular segment contributing to HPV is the intra-acinar artery. Here, we describe our protocol for the analysis of HPV of murine pulmonary vessels with diameters of 20-100 &mu;m.

マウス精密切り出肺スライスを用いた低酸素肺血管収縮のビデオモルフォメトリクス解析

Acute alveolar hypoxia causes pulmonary vasoconstriction (HPV) - also known as von Euler-Liljestrand mechanism - which serves to match lung perfusion to ...

Automated Measurement of Pulmonary Emphysema and Small Airway Remodeling in Cigarette Smoke-exposed Mice

COPD is projected to be the third most common cause of mortality world-wide by 2020(1). Animal models of COPD are used to identify molecules that contribute to the disease process and to test the efficacy of novel therapies for COPD. Researchers use a number of models of COPD employing different species including rodents, guinea-pigs, rabbits, and dogs(2). However, the most widely-used model is that in which mice are exposed to cigarette smoke. Mice are an especially useful species in which to model COPD because their genome can readily be manipulated to generate animals that are either deficient in, or over-express individual proteins. Studies of gene-targeted mice that have been exposed to cigarette smoke have provided valuable information about the contributions of individual molecules to different lung pathologies in COPD(3-5). Most studies have focused on pathways involved in emphysema development which contributes to the airflow obstruction that is characteristic of COPD. However, small airway fibrosis also contributes significantly to airflow obstruction in human COPD patients(6), but much less is known about the pathogenesis of this lesion in smoke-exposed animals. To address this knowledge gap, this protocol quantifies both emphysema development and small airway fibrosis in smoke-exposed mice. This protocol exposes mice to CS using a whole-body exposure technique, then measures respiratory mechanics in the mice, inflates the lungs of mice to a standard pressure, and fixes the lungs in formalin. The researcher then stains the lung sections with either Gill&#8217;s stain to measure the mean alveolar chord length (as a readout of emphysema severity) or Masson&#8217;s trichrome stain to measure deposition of extracellular matrix (ECM) proteins around small airways (as a readout of small airway fibrosis). Studies of the effects of molecular pathways on both of these lung pathologies will lead to a better understanding of the pathogenesis of COPD.

The goal of this protocol is to provide automated methods to quantify chronic lung pathologies in a murine model of COPD. The protocol includes exposing mice to cigarette smoke (CS), measuring pulmonary function, inflating the lungs, and using morphometry methods to measure emphysema and small airway remodeling in mice.

肺気腫とタバコ煙曝露マウスにおける末梢気道リモデリングの自動測定

COPD is projected to be the third most common cause of mortality world-wide by 2020(1).  Animal models of COPD are used to identify molecules that ...

Characterization of the Isolated, Ventilated, and Instrumented Mouse Lung Perfused with Pulsatile Flow

The isolated, ventilated and instrumented mouse lung preparation allows steady and pulsatile pulmonary vascular pressure-flow relationships to be measured with independent control over pulmonary arterial flow rate, flow rate waveform, airway pressure and left atrial pressure. Pulmonary vascular resistance is calculated based on multi-point, steady pressure-flow curves; pulmonary vascular impedance is calculated from pulsatile pressure-flow curves obtained at a range of frequencies. As now recognized clinically, impedance is a superior measure of right ventricular afterload than resistance because it includes the effects of vascular compliance, which are not negligible, especially in the pulmonary circulation. Three important metrics of impedance - the zero hertz impedance Z0, the characteristic impedance ZC, and the index of wave reflection RW - provide insight into distal arterial cross-sectional area available for flow, proximal arterial stiffness and the upstream-downstream impedance mismatch, respectively. All results obtained in isolated, ventilated and perfused lungs are independent of sympathetic nervous system tone, volume status and the effects of anesthesia. We have used this technique to quantify the impact of pulmonary emboli and chronic hypoxia on resistance and impedance, and to differentiate between sites of action (i.e., proximal vs. distal) of vasoactive agents and disease using the pressure dependency of ZC. Furthermore, when these techniques are used with the lungs of genetically engineered strains of mice, the effects of molecular-level defects on pulmonary vascular structure and function can be determined.

The following protocol outlines the process of isolating, ventilating and instrumenting mouse lungs to measure steady or pulsatile pulmonary vascular pressure-flow relationships in order to quantify the effects of blood flow, airflow, airway changes and vascular changes on right ventricular afterload.

絶縁型、ベンチレーテッド、および計装のマウス肺の特性評価は、拍動流を灌流

The isolated, ventilated and instrumented mouse lung preparation allows steady and pulsatile pulmonary vascular pressure-flow relationships to be measured ...

生物学

Evaluation of Respiratory System Mechanics in Mice using the Forced Oscillation Technique

The forced oscillation technique (FOT) is a powerful, integrative and translational tool permitting the experimental assessment of lung function in mice in a comprehensive, detailed, precise and reproducible manner. It provides measurements of respiratory system mechanics through the analysis of pressure and volume signals acquired in reaction to predefined, small amplitude, oscillatory airflow waveforms, which are typically applied at the subject's airway opening. The present protocol details the steps required to adequately execute forced oscillation measurements in mice using a computer-controlled piston ventilator (flexiVent; SCIREQ Inc, Montreal, Qc, Canada). The description is divided into four parts: preparatory steps, mechanical ventilation, lung function measurements, and data analysis. It also includes details of how to assess airway responsiveness to inhaled methacholine in anesthetized mice, a common application of this technique which also extends to other outcomes and various lung pathologies. Measurements obtained in na&iuml;ve mice as well as from an oxidative-stress driven model of airway damage are presented to illustrate how this tool can contribute to a better characterization and understanding of studied physiological changes or disease models as well as to applications in new research areas.

The present protocol provides a detailed step-by-step description of the procedures required to execute measurements of respiratory system mechanics as well as the assessment of airway responsiveness to inhaled methacholine in mice using the forced oscillation technique (flexiVent; SCIREQ Inc, Montreal, Qc, Canada).

強制振動法を用いたマウスにおける呼吸器系の力学の評価

The  forced oscillation technique (FOT) is a powerful, integrative and translational  tool permitting the experimental assessment of lung function in mice ...

Lung Fixation under Constant Pressure for Evaluation of Emphysema in Mice

Emphysema is a significant feature of chronic obstructive pulmonary disease (COPD). Studies involving an emphysematous mouse model require optimal lung fixation to produce reliable histological specimens of the lung. Due to the nature of the lung&rsquo;s structural composition, which consists largely of air and tissue, there is a risk that it collapses or deflates during the fixation process. Various lung fixation methods exist, each of which has its own advantages and disadvantages. The lung fixation method presented here utilizes constant pressure to enable optimal tissue evaluation for studies using an emphysematous mouse lung model. The main advantage is that it can fix many lungs with the same condition at one time. Lung specimens are obtained from chronic cigarette smoke-exposed mice. Lung fixation is performed using specialized equipment that enables the production of constant pressure. This constant pressure maintains the lung in a reasonably inflated state. Thus, this method generates a histological specimen of the lung that is suitable to evaluate cigarette smoke-induced mild emphysema.

Presented here is a useful protocol for lung fixation that creates a stable condition for histological evaluate of lung specimens from a mouse model of emphysema. The main advantage of this model is that it can fix many lungs with the same constant pressure without lung collapse or deflation.

マウスにおける気腫の評価に対する一定圧力下での肺固定

Emphysema is a significant feature of chronic obstructive pulmonary disease (COPD). Studies involving an emphysematous mouse model require optimal lung ...

Measuring Respiratory Function in Mice Using Unrestrained Whole-body Plethysmography

Respiratory dysfunction is one of the leading causes of morbidity and mortality in the world and the rates of mortality continue to rise. Quantitative assessment of lung function in rodent models is an important tool in the development of future therapies. Commonly used techniques for assessing respiratory function including invasive plethysmography and forced oscillation. While these techniques provide valuable information, data collection can be fraught with artefacts and experimental variability due to the need for anesthesia and/or invasive instrumentation of the animal. In contrast, unrestrained whole-body plethysmography (UWBP) offers a precise, non-invasive, quantitative way by which to analyze respiratory parameters. This technique avoids the use of anesthesia and restraints, which is common to traditional plethysmography techniques. This video will demonstrate the UWBP procedure including the equipment set up, calibration and lung function recording. It will explain how to analyze the collected data, as well as identify experimental outliers and artefacts that results from animal movement. The respiratory parameters obtained using this technique include tidal volume, minute volume, inspiratory duty cycle, inspiratory flow rate and the ratio of inspiration time to expiration time. UWBP does not rely on specialized skills and is inexpensive to perform. A key feature of UWBP, and most appealing to potential users, is the ability to perform repeated measures of lung function on the same animal.

The assessment of respiratory physiology has traditionally relied upon techniques, which require restraint or sedation of the animal. Unrestrained whole-body plethysmography, however, provides precise, non-invasive, quantitative analysis of respiratory physiology in animal models. In addition, the technique allows repeated respiratory assessment of mice allowing for longitudinal studies.

拘束されていない全身プレチスモグラフィを使用したマウスにおける呼吸機能の測定

Respiratory dysfunction is one of the leading causes of morbidity and mortality in the world and the rates of mortality continue to rise. Quantitative ...