この作品はRISystem AG、ダボス、スイスによってサポートされていました。

すべての手順はIACUCが承認したと制度ガイドライン（LandesamtエリーゼVerbraucherschutz、ZentralstelleAmtstierärztlicherDienst、ザールブリュッケン、ドイツ）を行いました。鎮痛および感染予防は、実験を行うべきであり、国や機関のそれぞれのガイドラインと一致する必要があります。 インプラントや手術器具の作製<ol><li>顕微計器箱からメスの刃（サイズ15）、小準備はさみ、細かい鉗子、ドレッシング鉗子、小さなはさみ、24ゲージ（G）と27 G針、非吸収性縫合糸5-0、および針ホルダを選択。 </li><li>髄内釘、連動ピン、特別な照準装置を箱から取り出し、ジリが見た、ジーリのテンプレートは、センタリングドリルビット（直径1mm）、ドリルビット（直径0.3mm）、およびハンドドリル（ 図を見て2;材料のリストを参照してください）。 注：intramedullary釘（直径0.8mm、15.7ミリメートルの長さ）は、大腿骨への逆行性注入のための医療グレードのステンレス鋼製の髄内釘のロックです。釘は、近位ねじ山（4ミリメートルの長さ）と、軸方向及び回転の安定性（ 図1）を達成するために、インターロックピン（直径0.3mm）を挿入するための2つの穴を有しています。 </li><li> 5分間消毒溶液（ 例えば、96％アルコール）に移植し、すべての手術器具を公開したり（蒸気滅菌、130℃、25分）、それらを滅菌します。消毒または滅菌後、無菌操作布の上に機器を配置します。小動物動作テーブルに直接隣接し、無菌操作布を置きます。 </li></ol> 2.動物、麻酔、および鎮痛<ol><li>研究と対処すべき質問のために必要に応じてマウスの系統、年齢、性別を選択してください。 注：この研究のために、12〜14週齢の雄CD-1マウスを用いました。ネイルimplaのため35グラム - ntationは、動物の理想体重は25です。 </li><li> 15ミリグラム/ kgのキシラジンおよび75 mgの/ kgのケタミンの腹腔内注射でマウスを麻酔。つま先のピンチによって麻酔を確認してください。麻酔中の乾燥から動物の目を保護するために目の潤滑剤を塗布します。麻酔の誘導後、体温を一定に保つために加熱ランプ下にマウスを置きます。 </li><li>手術後3日目までは手術の前に1日目から鎮痛のための飲料水（2.5ミリグラム/ 100ミリリットル）にトラマドール塩酸塩を適用します。 </li></ol> 3.外科的手順とネイル移植<ol><li>手術前に、全体の右後肢を剃ると脱毛クリームを適用します。 5分後、クリームを除去し、水で足をきれいに。消毒溶液（ 例えば 、96％アルコール）に移植し、すべての手術器具を公開したり（蒸気滅菌、130℃、25分）、それらを滅菌します。 </li><li>無菌条件下では、畝を配置小動物の操作テーブルの上に仰臥位で、SE。膝の顆に前方アプローチを可能にするために右ひざを曲げます。手術用メスの刃を使用して、右膝に5ミリメートル内側parapatellar切開を行います。 </li><li>細かいピンセットで膝蓋靱帯を持ち上げて、手術用メスの刃で慎重に靭帯を動員。その後、大腿骨の顆間ノッチを露出させるために、メスの刃で横方向に膝蓋骨をシフト。 </li><li>髄内腔に到達するまで穿孔することによって顆間ノッチを開きます。 <ol><li>ドリルビットを中心に1ミリメートルを使用して、大腿骨軸に対してオフセット45°で掘削を開始します。ゆっくりと、それは大腿骨の骨軸と平行になるまで掘削中にドリルビットの方向を変えます。髄内空洞に達した場合はドリル停止します。 </li></ol></li><li>顆間窩に骨を開いた後、大腿骨の全長にわたって髄内キャビティに24 G針を挿入します。 intrameを連手動で24 G針の回転運動を通して大腿骨のdullary空洞。 24 G針を外し、髄内キャビティにシンナー27 G針を挿入します。大転子で近位大腿骨の皮質骨を穿孔するために前方に針を押してください。 </li><li>大腿骨から27 G針を外します。爪の先端が顆のレベルに達するまで、ハンドドリルを使用して、連続的な回転及び軸方向圧下顆間ノッチを通って髄内釘を打ち込みます。 注：爪の先端が小さいマークで識別することができます。 </li><li>左側臥位にマウスを置きます。外科的に大腿骨の中間シャフトを露出させるために股関節に膝関節からの横方向の大腿骨の骨幹部分に沿ってメスの刃を使用して、縦方向の皮膚切開を行います。 </li><li>小さな準備ハサミを使用して、筋膜を分割し、側方からの大腿骨軸の方向に筋肉を広げました。大腿骨の骨幹の一部が露出するまでの筋肉を広げます。坐骨神経を保持します。 <ol><li>ドレッシング鉗子で骨を損なうことにより、大腿骨の全周を準備します。次に、ドレッシング鉗子を広げることによって筋肉を撤回し、大腿骨を露出させます。 </li></ol></li><li>爪の先端に照準装置をマウントします。それは爪のアダプタフランジに取り付けられるまで、デバイスを前進させ、大腿骨の前外側の位置に照準装置の電源を入れます。 </li><li>近位および遠位連動ピンと釘を連動。 <ol><li>近位の連動ピンと起動します。 </li><li>ハンドドリルにセンタリングドリルビット（直径1mm）を挿入します。近位の連動穴位置で骨を皿穴。 注：皿穴により、小さな空洞が骨ドリルスルーせずに面した皮質骨に作成されます。この空洞は、薄いドリルビット（直径0.3mm）の改善されたセンタリングと案内が可能になり、後で使用。 </li><li>ハンドドリルにドリルビット（直径0.3mm）を挿入します。照準装置を使用して、対面および回避皮質骨（bicortical）の両方に穴を開けます。照準装置を介して第1連動ピンを挿入します。すぐに連動トルクが達成されるようにオフ連動ピン駆動軸ばさみ。 </li><li>遠位連動ピンに対して、この手順を繰り返します。 </li></ol></li><li>骨幹骨切り術を行います。 <ol><li> 2インターロックピン間の側面に照準装置に鋸ガイドを取り付けます。そして、ジリと骨は生理食塩水で連続灌漑の下で見た見ました。骨切り術が完了した後、骨に近い、一端でのこぎりをカット。軟組織への損傷を引き起こすことを避けるために慎重にのこぎりを削除します。 </li></ol></li><li>標線で髄内釘の残りのシャフトをオフクリップ、小さなペンチで、照準装置を取り外します。 </li><li>緯度で筋肉層を閉じます大腿骨のERALサイトと単一縫合糸で皮膚閉鎖を行います。膝の前方サイトでは、膝蓋骨の位置を変更し、単一の縫合糸で筋肉に膝蓋骨腱を固定します。同様に、この傷を閉じるために、単一の縫合糸を使用してください。 </li><li>彼らは麻酔から回復するまで加熱ランプの下で動物を保管してください。彼らは腹側横臥位を維持するのに十分な意識を取り戻してきたまでは無人の動物を放置しないでください。動物施設内の単一のケージに動物を返します。 </li><li>毎日慎重に動物を監視します。最初の3日間に術後鎮痛を維持します。発声、落ち着きのなさ、移動性の欠如、グルーミングの失敗、異常な姿勢、そして周囲の正常な関心の欠如によって示されるようにあれば鎮痛を続行し、手術後4日目に、動物はまだ、痛みの証拠を示します。動物が痛み自由であるとき鎮痛を終了します。 </li></ol>

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Romano Matthys is an employee of RISystem AG, Davos, Switzerland, which produces the implants and implant-specific instruments. The other authors have no conflicts of interest.

外科技術の最も重要なステップは、爪の正確な位置決め、照準装置、およびピンです。爪は、顆のレベルで膝関節への爪の突起が膝（ 図3 A）の動きを制限することができるので、爪の先端にマークされたインデントに完全に挿入しなければなりません。したがって、大腿骨の大きさとは、従って、動物の体重を考慮しなければなりません。外科医はまた、爪のアダプタフランジ?...

骨治癒の生物学、細胞およびスフェロイド培養物を用いてインビトロで研究することができるが、それはまた、動物研究を使用して近づく、インビボで必要です。大動物実験はまだ前臨床試験において重要な役割を果たしているが、製品や仮説の初期段階のテストでは、過去10年の間に変更されており、今日では多くの場合、小動物モデル1で行われます。このスイッチは、いくつかの理由のために実施しました。マウスおよびラットの生産とメンテナンスは豚や羊に比べて安くなっています。また、小動物は、慢性実験の大規模シリーズの性能を容易にどちらも短い再生時間と短く、通常の治癒期間を有します。最後に、遺伝子標的動物と特異的抗体の利用可能性は、骨治癒の分子メカニズムの分析を可能にします。以前より大きな動物モデルにおいて骨接合技術を使用しながら、しかし、最小限のvariatで翻訳することができました<html>ヒトまたは動物の臨床患者のケアに使用される同様の手順からのイオンは、小型ラットおよびマウスにおける骨接合技術の開発及び適用は、困難であることが判明しました。 十分に生体力学的環境が著しく骨治癒プロセス2に影響を与えることが知られています。 micromovementsと剛性の低い固定後の剛性固定および軟骨内骨化後の膜内骨化を含む、ヒトにおける骨折治癒、治癒の異なるモードでの骨折安定化結果の違いから知られているように。完全な軸または回転不安定性は、治癒プロセスを遅延させることができるか、非組合3になることがあります。従って、我々は、マウスおよびラットで洗練されたインプラントシステムと骨接合技術の開発が必要であると感じています。このようにして、生体力学的条件は、治癒過程を分析するときに有効な結果を保証し、適切に標準化することができます。 e_content &quot;&gt;高度に洗練されたネズミの安定化技術の相当数は、ここ数年の間に導入されているが、最も一般的に使用される技術はまだ簡単な髄内ピンである。この技術の主な欠点は、しかし、回転および軸方向の欠如であります安定性4。回転および軸方向の安定性を向上させるために、髄内スクリューは、マウス5に大腿骨の骨折を安定化するために導入された。しかし、ねじ固定が原因で骨片の間の接触および圧縮の必要性骨欠損の治癒を分析するために使用することができません回転安定性を維持するために。 爪をロック髄内はシンプルなピンと髄内スクリュー4と比較して、より高い軸方向および回転安定性を提供しています。なぜならジーリのためのガイドの可能性の高い再現性大腿骨骨切り術は、見て、定義されたギャップサイズを作成する機能は、通常のボン両方の分析を可能にします電子治癒および骨欠損の治癒6。インターロックピンを挿入する、爪をロック髄内は、全重量を保有しながらも、全体の治癒過程の間に一定のギャップの大きさを保証します。ここでは、正常および遅延骨治癒に関する実験的研究で、その長所と短所の髄内固定釘の設計と応用について報告するだけでなく、。

<table><tbody><tr><td>MouseNail</td><td>RISystem AG</td><td>221,122</td><td></td></tr><tr><td>MouseNail aiming device</td><td>RISystem AG</td><td>221,201</td><td></td></tr><tr><td>MouseNail interlocking pin</td><td>RISystem AG</td><td>221,121</td><td></td></tr><tr><td>Centering bit</td><td>RISystem AG</td><td>592,205</td><td></td></tr><tr><td>Drill bit</td><td>RISystem AG</td><td>590,200</td><td></td></tr><tr><td>Gigli wire saw</td><td>RISystem AG</td><td>590,100</td><td></td></tr><tr><td>Suture (5-0 Prolene)</td><td>Ethicon</td><td>8614H</td><td></td></tr><tr><td>Forceps</td><td>Braun Aesculap AG &amp;amp;CoKG&amp;nbsp;</td><td>BD520R</td><td></td></tr><tr><td>Dressing forceps</td><td>Braun Aesculap AG &amp;amp;CoKG&amp;nbsp;</td><td>BJ009R</td><td></td></tr><tr><td>Scissors</td><td>Braun Aesculap AG &amp;amp;CoKG&amp;nbsp;</td><td>BC100R</td><td></td></tr><tr><td>Needle holder</td><td>Braun Aesculap AG &amp;amp;CoKG&amp;nbsp;</td><td>BM024R</td><td></td></tr><tr><td>24 G needle</td><td>BD Mircolance 3</td><td>304100</td><td></td></tr><tr><td>27 G needle</td><td>Braun Melsungen AG</td><td>9186182</td><td></td></tr><tr><td>Scalpel blade size 15</td><td>Braun Aesculap AG &amp;amp;CoKG&amp;nbsp;</td><td>16600525</td><td></td></tr><tr><td>Pincers</td><td>Knipex</td><td>7932125</td><td></td></tr><tr><td>Heat radiator</td><td>Sanitas</td><td>605.25</td><td></td></tr><tr><td>Depilatory cream</td><td>Asid bonz GmbH</td><td>NDXZ10</td><td></td></tr><tr><td>Eye lubricant</td><td>Bayer Vital GmbH</td><td>2182442</td><td></td></tr><tr><td>Xylazine</td><td>Bayer Vital GmbH</td><td>1320422</td><td></td></tr><tr><td>Ketamine</td><td>Serumwerke Bernburg</td><td>7005294</td><td></td></tr><tr><td>Tramadol</td><td>Gr&amp;uuml;nenthal GmbH</td><td>2256241</td><td></td></tr><tr><td>Disinfection solution (SoftaseptN)</td><td>Braun Melsungen AG</td><td>8505018</td><td></td></tr><tr><td>CD-1 mice</td><td>Charles River</td><td>22</td><td></td></tr></tbody></table>

an intramedullary locking nail for standardized fixation of femur osteotomies to analyze normal and defective bone healing in mice

骨治癒モデルは、臨床的骨折の治療のための新しい治療戦略の開発に不可欠です。さらに、マウスモデルは、外傷の研​​究に使用されるより一般的になってきています。彼らは、骨治癒の高度に差別化プロセスの背後にある分子機構の解析のための変異株と多数の抗体を提供しています。生体力学的環境を制御するために、標準化された、よく特徴付けられた骨接合技術は、マウスでは必須です。ここでは、マウスにオープン大腿骨骨切り術を安定化させるための髄内釘の設計および使用について報告します。医療グレードのステンレス鋼製の釘は、高い軸方向と回転剛性を提供します。さらにインプラントは定義され、一定の骨切り術ギャップの作成は0.00ミリメートルから2.00ミリメートルにサイズができます。 0.00ミリメートルと0.25ミリメートルのギャップサイズの大腿骨骨切り術の爪の安定化をロックする髄内には、軟骨内および膜内ossificatを通じて十分な骨の治癒をもたらしますイオン。萎縮性非組合で2.00ミリメートル結果のギャップサイズと大腿骨骨切り術の安定化。従って、髄内釘のロックは、治癒および非治癒モデルで使用することができます。他のオープン骨治癒のモデルと比較して、爪の使用のさらなる利点は、十分に骨統合のプロセスを研究するために、代用骨と足場を固定するための可能性です。髄内釘の使用の欠点は、閉じられたモデルと比較すると、開いているすべての手順に固有のより侵襲的な外科的手技、です。さらなる欠点は、髄外安定化手順と比較して、すべての髄安定化技術に固有の髄内腔に何らかの損傷を誘導することができます。

外科的処置のための全体的な時間は、創傷閉鎖するために皮膚切開から約30分でした。提供される外科用インプラントを使用して、外科手術は、ステレオ顕微鏡なしで行うことができます。手術後、動物を毎日モニターしました。動物のどれもが、この期間の後の痛み（発声、落ち着きのなさ、移動性の欠如、グルーミングの失敗、異常な姿勢、または周囲の正常な?...

Watch this Scientific Journal Video about An Intramedullary Locking Nail for Standardized Fixation of Femur Osteotomies to Analyze Normal and Defective Bone Healing in Mice at JoVE.com

An Intramedullary Locking Nail for Standardized Fixation of Femur Osteotomies to Analyze Normal and Defective Bone Healing in Mice

This protocol describes an osteosynthesis technique using an intramedullary locking nail for standardized fixation of femur osteotomies, which can be used to analyze normal and defective bone healing in mice.

マウスにおける正常および不良骨治癒を分析するために大腿骨骨切り術の標準化された固定用髄内ロッキングネイル

Bone healing models are essential to the development of new therapeutic strategies for clinical fracture treatment. Furthermore, mouse models are becoming ...

an-intramedullary-locking-nail-for-standardized-fixation-femur

Research

JoVE Journal

Medicine

13.3K ビュー.  Saarland University. This protocol describes an osteosynthesis technique using an intramedullary locking nail for standardized fixation of femur osteotomies, which can be used to analyze normal and defective bone healing in mice.

ビデオ: An Intramedullary Locking Nail for Standardized Fixation of Femur Osteotomies to Analyze Normal and Defective Bone Healing in Mice

Creating Rigidly Stabilized Fractures for Assessing Intramembranous Ossification, Distraction Osteogenesis, or Healing of Critical Sized Defects

Assessing modes of skeletal repair is essential for developing therapies to be used clinically to treat fractures. Mechanical stability plays a large role in healing of bone injuries. In the worst-case scenario mechanical instability can lead to delayed or non-union in humans. However, motion can also stimulate the healing process. In fractures that have motion cartilage forms to stabilize the fracture bone ends, and this cartilage is gradually replaced by bone through recapitulation of the developmental process of endochondral ossification. In contrast, if a bone fracture is rigidly stabilized bone forms directly via intramembranous ossification. Clinically, both endochondral and intramembranous ossification occur simultaneously. To effectively replicate this process investigators insert a pin into the medullary canal of the fractured bone as described by Bonnarens4. This experimental method provides excellent lateral stability while allowing rotational instability to persist. However, our understanding of the mechanisms that regulate these two distinct processes can also be enhanced by experimentally isolating each of these processes. We have developed a stabilization protocol that provides rotational and lateral stabilization. In this model, intramembranous ossification is the only mode of healing that is observed, and healing parameters can be compared among different strains of genetically modified mice 5-7, after application of bioactive molecules 8,9, after altering physiological parameters of healing 10, after modifying the amount or time of stabilization 11, after distraction osteogenesis 12, after creation of a non-union 13, or after creation of a critical sized defect. Here, we illustrate how to apply the modified Ilizarov fixators for studying tibial fracture healing and distraction osteogenesis in mice.

This article describes a method for stabilizing long bone fractures that is based on the application of modified Ilizarov external fixators 1-3. After application of the fixators and creation of the bone injury, healing can be assessed, distraction osteogenesis can be performed, or non-union or critical sized defect can be created and used to study therapeutic interventions.

膜内骨化、仮骨延長術、またはCriticalサイズの欠損の治癒を評価するための剛安定骨折を作成する

Assessing modes of skeletal repair is essential for developing therapies to be used clinically to treat fractures. Mechanical stability plays a large role ...

医学

A Mini-Invasive Internal Fixation Technique for Studying Immobilization-Induced Knee Flexion Contracture in Rats

Joint contracture, resulting from a prolonged joint immobilization, is a common complication in orthopedics. Currently, utilizing an internal fixation to restrict knee joint mobility is a widely accepted model to generate experimental contracture. However, implanting application will inevitably cause surgical trauma to the animals. Aiming to develop a less invasive approach, we combined a muscle-gap separation modus with a previously reported mini-incision skill during the surgical procedure: Two mini skin incisions were made on the lateral thigh and leg, followed by performing muscle-gap separation to expose the bone surface. The rat knee joint was gradually immobilized by a preconstructed internal fixation at approximately 135&#176; knee flexion without interfering essential nerves or blood vessels. As expected, this simple technique permits rapid postoperative rehabilitation in animals. The correct position of the internal fixation was confirmed by an x-ray or micro-CT scanning analysis. The range of motion was significantly restricted in the immobilized knee joint than that observed in the contralateral knee joint demonstrating the effectiveness of this model. Besides, histological analysis revealed the development of fibrous deposition and adhesion in the posterior-superior knee joint capsule over time. Thus, this mini-invasive model may be suitable for mimicking the development of immobilized knee joint contracture.

Here, we present a protocol to describe a minimally invasive technique for knee joint immobilization in a rat model. This reproducible protocol, basing on muscle-gap separation modus and the mini-incision skill, is suitable for studying the underlying molecular mechanism of acquired joint contracture.

ラットの固定化誘発膝屈曲収縮を研究するための小型侵襲的内部固定技術

Joint contracture, resulting from a prolonged joint immobilization, is a common complication in orthopedics. Currently, utilizing an internal fixation to ...

発生生物学

A Simple Critical-sized Femoral Defect Model in Mice

While bone has a remarkable capacity for regeneration, serious bone trauma often results in damage that does not properly heal. In fact, one tenth of all limb bone fractures fail to heal completely due to the extent of the trauma, disease, or age of the patient. Our ability to improve bone regenerative strategies is critically dependent on the ability to mimic serious bone trauma in test animals, but the generation and stabilization of large bone lesions is technically challenging. In most cases, serious long bone trauma is mimicked experimentally by establishing a defect that will not naturally heal. This is achieved by complete removal of a bone segment that is larger than 1.5 times the diameter of the bone cross-section. The bone is then stabilized with a metal implant to maintain proper orientation of the fracture edges and allow for mobility. 
Due to their small size and the fragility of their long bones, establishment of such lesions in mice are beyond the capabilities of most research groups. As such, long bone defect models are confined to rats and larger animals. Nevertheless, mice afford significant research advantages in that they can be genetically modified and bred as immune-compromised strains that do not reject human cells and tissue.
Herein, we demonstrate a technique that facilitates the generation of a segmental defect in mouse femora using standard laboratory and veterinary equipment. With practice, fabrication of the fixation device and surgical implantation is feasible for the majority of trained veterinarians and animal research personnel. Using example data, we also provide methodologies for the quantitative analysis of bone healing for the model.

Animal models are frequently employed to mimic serious bone injury in biomedical research. Due to their small size, establishment of stabilized bone lesions in mice are beyond the capabilities of most research groups. Herein, we describe a simple method for establishing and analyzing experimental femoral defects in mice.

マウスの簡単な重要なサイズの大腿欠陥モデル

While bone has a remarkable capacity for regeneration, serious bone trauma often results in damage that does not properly heal. In fact, one tenth of all ...

Establishment of a Segmental Femoral Critical-size Defect Model in Mice Stabilized by Plate Osteosynthesis

The use of tissue-engineered bone constructs is an appealing strategy to overcome drawbacks of autografts for the treatment of massive bone defects. As a model organism, the mouse has already been widely used in bone-related research. Large diaphyseal bone defect models in mice, however, are sparse and often use bone fixation which fills the bone marrow cavity and does not provide optimal mechanical stability. The objectives of the current study were to develop a critical-size, segmental, femoral defect in nude mice. A 3.5-mm mid-diaphyseal femoral ostectomy (approximately 25% of the femur length) was performed using a dedicated jig, and was stabilized with an anterior located locking plate and 4 locking screws. The bone defect was subsequently either left empty or filled with a bone substitute (syngenic bone graft or coralline scaffold). Bone healing was monitored noninvasively using radiography and in vivo micro-computed-tomography and was subsequently assessed by ex vivo micro-computed-tomography and undecalcified histology after animal sacrifice, 10 weeks postoperatively. The recovery of all mice was excellent, a full-weight-bearing was observed within one day following the surgical procedure. Furthermore, stable bone fixation and consistent fixation of the implanted materials were achieved in all animals tested throughout the study. When the bone defects were left empty, non-union was consistently obtained. In contrast, when the bone defects were filled with syngenic bone grafts, bone union was always observed. When the bone defects were filled with coralline scaffolds, newly-formed bone was observed in the interface between bone resection edges and the scaffold, as well as within a short distance within the scaffold. 
The present model describes a reproducible critical-size femoral defect stabilized by plate osteosynthesis with low morbidity in mice. The new load-bearing segmental bone defect model could be useful for studying the underlying mechanisms in bone regeneration pertinent to orthopaedic applications.

Although mouse models are invaluable tools for bone tissue engineering, models of long bone defects are sparse. This need motivated development of the present protocol which uses a locking plate with four screws and a dedicated jig to perform and stabilize a reproducible, femoral, critical-size defect with low morbidity.

プレート骨接合によって安定化マウスにおけるセグメント別大腿臨界サイズ欠陥モデルの確立

The use of tissue-engineered bone constructs is an appealing strategy to overcome drawbacks of autografts for the treatment of massive bone defects. As a ...

In Vivo Evaluation of Fracture Callus Development During Bone Healing in Mice Using an MRI-compatible Osteosynthesis Device for the Mouse Femur

Endochondral fracture healing is a complex process involving the development of fibrous, cartilaginous, and osseous tissue in the fracture callus. The amount of the different tissues in the callus provides important information on the fracture healing progress. Available in vivo techniques to longitudinally monitor the callus tissue development in preclinical fracture-healing studies using small animals include digital radiography and &#181;CT imaging. However, both techniques are only able to distinguish between mineralized and non-mineralized tissue. Consequently, it is impossible to discriminate cartilage from fibrous tissue. In contrast, magnetic resonance imaging (MRI) visualizes anatomical structures based on their water content and might therefore be able to noninvasively identify soft tissue and cartilage in the fracture callus. Here, we report the use of an MRI-compatible external fixator for the mouse femur to allow MRI scans during bone regeneration in mice. The experiments demonstrated that the fixator and a custom-made mounting device allow repetitive MRI scans, thus enabling longitudinal analysis of fracture-callus tissue development.

In Vivo Evaluation of Fracture Callus Development During Bone Healing in Mice Using an MRI-compatible Osteosynthesis Device for the Mouse Femur

The evaluation of tissue development in the fracture callus during endochondral bone healing is essential to monitor the healing process. Here, we report the use of a magnetic resonance imaging (MRI)-compatible external fixator for the mouse femur to allow MRI scans during bone regeneration in mice.

生体内で破壊カルス開発マウス大腿骨の骨、MRI 対応のデバイスを用いたマウスの骨治癒過程の評価

Endochondral fracture healing is a complex process involving the development of fibrous, cartilaginous, and osseous tissue in the fracture callus. The ...

A Mouse Model of Orthopedic Surgery to Study Postoperative Cognitive Dysfunction and Tissue Regeneration

Surgery is commonly used to improve and maintain quality of life. Unfortunately, in vulnerable patients such as the elderly, complications may occur and significantly diminish the outcome. Indeed, after routine orthopedic surgery to repair a fracture, as many as 50% of elderly patients suffer from neurologic complications like delirium. Also, the capacity to heal and regenerate tissue after surgery decreases with age, and can impact the quality of fracture repair and even osseous integration of implants. Thus, a better understanding of mechanisms that drive these age-dependent changes could provide strategic targets to minimize risk for such complications and optimize outcomes. Here, we introduce a clinically relevant mouse model of tibial fracture. The postoperative changes in these mice mimic some of the cognitive impairments commonly observed after routine orthopedic surgery in humans. Briefly, an incision is performed in the right hind limb under strictly aseptic conditions. Muscles are disassociated, and a 0.38-mm stainless steel pin is inserted into the upper crest of the tibia, inside the intramedullary canal. Osteotomy is then performed, and the wound is stapled. We have used this model to investigate the effects of surgical trauma on postoperative neuroinflammation and behavioral changes. By applying this fracture model in combination with parabiosis, a surgical model in which 2 mice are anastomosed, we have studied cells and secreted factors that systemically rejuvenate organ function and tissue regeneration after injury. By following our step-by-step protocol, these models can be reproduced with high fidelity, and can be adapted to interrogate many biologic pathways that are altered by surgical trauma.

This protocol describes a mouse model of orthopedic surgery that has been used to study mechanisms of postoperative neuroinflammation and behavioral changes, and when combined with parabiosis, to study tissue regeneration during aging.

整形外科術後の高次脳機能障害と組織再生を研究するマウス モデル

Surgery is commonly used to improve and maintain quality of life. Unfortunately, in vulnerable patients such as the elderly, complications may occur and ...

A Minimally Invasive Model to Analyze Endochondral Fracture Healing in Mice Under Standardized Biomechanical Conditions

Bone healing models are necessary to analyze the complex mechanisms of fracture healing to improve clinical fracture treatment. During the last decade, an increased use of mouse models in orthopedic research was noted, most probably because mouse models offer a large number of genetically-modified strains and special antibodies for the analysis of molecular mechanisms of fracture healing. To control the biomechanical conditions, well-characterized osteosynthesis techniques are mandatory, also in mice. Here, we report on the design and use of a closed bone healing model to stabilize femur fractures in mice. The intramedullary screw, made of medical-grade stainless steel, provides through fracture compression an axial and rotational stability compared to the mostly used simple intramedullary pins, which show a complete lack of axial and rotational stability. The stability achieved by the intramedullary screw allows the analysis of endochondral healing. A large amount of callus tissue, received after stabilization with the screw, offers ideal conditions to harvest tissue for biochemical and molecular analyses. A further advantage of the use of the screw is the fact that the screw can be inserted into the femur with a minimally invasive technique without inducing damage to the soft tissue. In conclusion, the screw is a unique implant that can ideally be used in closed fracture healing models offering standardized biomechanical conditions.

This protocol describes a minimally invasive osteosynthesis technique using an intramedullary screw for standardized stabilization of femur fractures, which can be used to analyze endochondral bone healing in mice.

癒しの標準化された生体力学的条件下でマウスの軟骨破壊を分析する低侵襲モデル

Bone healing models are necessary to analyze the complex mechanisms of fracture healing to improve clinical fracture treatment. During the last decade, an ...

The Generation of Closed Femoral Fractures in Mice: A Model to Study Bone Healing

Bone fractures impose a tremendous socio-economic burden on patients, in addition to significantly affecting their quality of life. Therapeutic strategies that promote efficient bone healing are non-existent and in high demand. Effective and reproducible animal models of fractures healing are needed to understand the complex biological processes associated with bone regeneration. Many animal models of fracture healing have been generated over the years; however, murine fracture models have recently emerged as powerful tools to study bone healing. A variety of open and closed models have been developed, but the closed femoral fracture model stands out as a simple method for generating rapid and reproducible results in a physiologically relevant manner. The goal of this surgical protocol is to generate unilateral closed femoral fractures in mice and facilitate a post-fracture stabilization of the femur by inserting an intramedullary steel rod. Although devices such as a nail or a screw offer greater axial and rotational stability, the use of an intramedullary rod provides a sufficient stabilization for consistent healing outcomes without producing new defects in the bone tissue or damaging nearby soft tissue. Radiographic imaging is used to monitor the progression of callus formation, bony union, and subsequent remodeling of the bony callus. Bone healing outcomes are typically associated with the strength of the healed bone and measured with torsional testing. Still, understanding the early cellular and molecular events associated with fracture repair is critical in the study of bone tissue regeneration. The closed femoral fracture model in mice with intramedullary fixation serves as an attractive platform to study bone fracture healing and evaluate therapeutic strategies to accelerate healing.

The murine closed femoral fracture model is a powerful platform to study fracture healing and novel therapeutic strategies to accelerate bone regeneration. The goal of this surgical protocol is to generate unilateral closed femoral fractures in mice using an intramedullary steel rod to stabilize the femur.

マウスで閉じた大腿骨骨折の生成: 骨の治癒を研究するためのモデル

Bone fractures impose a tremendous socio-economic burden on patients, in addition to significantly affecting their quality of life. Therapeutic strategies ...

Fracture Apparatus Design and Protocol Optimization for Closed-stabilized Fractures in Rodents

The reliable generation of consistent stabilized fractures in animal models is essential for understanding the biology of bone regeneration and developing therapeutics and devices. However, available injury models are plagued by inconsistency resulting in wasted animals and resources and imperfect data. To address this problem of fracture heterogeneity, the purpose of the method described herein is to optimize fracture generation parameters specific to each animal and yield a consistent fracture location and pattern. This protocol accounts for variations in bone size and morphology that may exist between mouse strains and can be adapted to generate consistent fractures in other species, such as rat. Additionally, a cost-effective, adjustable fracture apparatus is described. Compared to current stabilized fracture techniques, the optimization protocol and new fracture apparatus demonstrate increased consistency in stabilized fracture patterns and locations. Using optimized parameters specific to the sample type, the described protocol increases the precision of induced traumas, minimizing the fracture heterogeneity typically observed in closed-fracture generation procedures.

The goal of the protocol is to optimize the fracture generation parameters to yield consistent fractures. This protocol accounts for the variations in bone size and morphology that may exist between animals. Additionally, a cost-effective, adjustable fracture apparatus is described.

破壊装置設計と齧歯動物で閉じて安定骨折に対するプロトコルの最適化

The reliable generation of consistent stabilized fractures in animal models is essential for understanding the biology of bone regeneration and developing ...

Transverse Fracture of the Mouse Femur with Stabilizing Pin

Fracture repair is an essential function of the skeleton that cannot be reliably modeled in vitro. A mouse injury model is an efficient approach to test whether a gene, gene product or drug influences bone repair because murine bones recapitulate the stages observed during human fracture healing. When a mouse or human breaks a bone, an inflammatory response is initiated, and the periosteum, a stem cell niche surrounding the bone itself, is activated and expands. Cells residing in the periosteum then differentiate to form a vascularized soft callus. The transition from the soft callus to a hard callus occurs as the recruited skeletal progenitor cells differentiate into mineralizing cells, and the bridging of the fractured ends results in the bone union. The mineralized callus then undergoes remodeling to restore the original shape and structure of the healed bone. Fracture healing has been studied in mice using various injury models. Still, the best way to recapitulate this entire biological process is to break through the cross-section of a long bone that encompasses both cortices. This protocol describes how a stabilized, transverse femur fracture can be safely performed to assess healing in adult mice. A surgical protocol including detailed harvesting and imaging techniques to characterize the different stages of fracture healing is also provided.

This protocol describes a method to perform fractures on adult mice and monitor the healing process.

安定化ピン付きマウス大腿骨の横骨折

Fracture repair is an essential function of the skeleton that cannot be reliably modeled in vitro. A mouse injury model is an efficient approach to test ...

マウスにおける正常および不良骨治癒を分析するために大腿骨骨切り術の標準化された固定用髄内ロッキングネイル

要約

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この動画の章

膜内骨化、仮骨延長術、またはCriticalサイズの欠損の治癒を評価するための剛安定骨折を作成する

ラットの固定化誘発膝屈曲収縮を研究するための小型侵襲的内部固定技術

マウスの簡単な重要なサイズの大腿欠陥モデル

プレート骨接合によって安定化マウスにおけるセグメント別大腿臨界サイズ欠陥モデルの確立

生体内で破壊カルス開発マウス大腿骨の骨、MRI 対応のデバイスを用いたマウスの骨治癒過程の評価

整形外科術後の高次脳機能障害と組織再生を研究するマウスモデル

癒しの標準化された生体力学的条件下でマウスの軟骨破壊を分析する低侵襲モデル

マウスで閉じた大腿骨骨折の生成: 骨の治癒を研究するためのモデル

破壊装置設計と齧歯動物で閉じて安定骨折に対するプロトコルの最適化

安定化ピン付きマウス大腿骨の横骨折

マウスにおける正常および不良骨治癒を分析するために大腿骨骨切り術の標準化された固定用髄内ロッキングネイル

要約

さらに動画を探す

この動画の章

膜内骨化、仮骨延長術、またはCriticalサイズの欠損の治癒を評価するための剛安定骨折を作成する

ラットの固定化誘発膝屈曲収縮を研究するための小型侵襲的内部固定技術

マウスの簡単な重要なサイズの大腿欠陥モデル

プレート骨接合によって安定化マウスにおけるセグメント別大腿臨界サイズ欠陥モデルの確立

生体内で破壊カルス開発マウス大腿骨の骨、MRI 対応のデバイスを用いたマウスの骨治癒過程の評価

整形外科術後の高次脳機能障害と組織再生を研究するマウス モデル

癒しの標準化された生体力学的条件下でマウスの軟骨破壊を分析する低侵襲モデル

マウスで閉じた大腿骨骨折の生成: 骨の治癒を研究するためのモデル

破壊装置設計と齧歯動物で閉じて安定骨折に対するプロトコルの最適化

安定化ピン付きマウス大腿骨の横骨折

整形外科術後の高次脳機能障害と組織再生を研究するマウスモデル