The authors thank members of the Valdez laboratory for intellectual input on experiments and comments on the manuscript.

全ての実験は、NIHガイドラインとバージニア工科大学施設内動物管理使用委員会によって承認された動物プロトコルの下で行いました。 外科1.準備動物<ol><li>滅菌した1 mlのインスリンシリンジで、皮下鼠径注射ケタミンの混合物（90ミリグラム/ kg）およびキシラジン（10mg / kg）でマウスを麻酔。キャリア溶液は、0.9％生理食塩水、17.4 mg / mlでケタミン、および2.6 mg / mlとキシラジンの混合物が含まれています。有効にする薬を待っている間にケージに戻って動物を置きます。 注：負荷用量は処置の持続時間のために十分な麻酔を提供しない場合は、負荷用量の追加の25％が注入されてもよいです。 </li><li>モニターの動物は着実に呼吸数と覚醒レベルの適切なうつ病をチェックするために注射を投稿してください。十分に麻酔をかけたときに何の応答を惹起してはならない後足のピンチで覚醒レベルを確認します。 注：これは通常3-5かかります25〜30グラムを平均し、若い成体マウス分間。動物は、10分後の注射後も応答する場合、麻酔負荷用量の追加の25％が注入されてもよいです。 </li><li>乾燥を防ぐために動物の目にワセリンと軽鉱油眼軟膏を適用します。ケージから動物を取り外し、きれいな、平らな面に置きます。手足の唯一の外側面を露出させ、電気ヘアトリマーを使用して、骨盤に足から所望の後肢を剃ります。 </li><li> 1分間剃らサイトに化学脱毛剤を適用します。手動の実験室ワイプを使用して髪を削除します。実験室できれいに脱毛エリアをエタノールに浸したワイプ。 </li></ol> 2.外科的手順<ol><li>オートクレーブまたは他の適切なメソッドを介して手術器具を滅菌します。 80％エタノール/ H 2 0と、手術部位や手術用ボードを清掃してください。 proviodineで手術部位を消毒します。手術用ボード上にマウスを置き、手足の拘束と合わせます。キープ膝関節と解剖学的に自然な位置にターゲット後肢がわずかに内部または外部回転させずに拡張しました。 </li><li>手術用顕微鏡下で動物とボードを置きます。表面的なランドマークの触診、特に骨膝関節と前脛骨筋と腓腹筋の筋肉の間の尾根を経由して、適切な切開部位へのオリエント。 </li><li>把持するための一般的な鉗子を使用しながら、メスやスプリングはさみを使って皮膚を介して約3cmの切開を行います。共通の腓骨神経の基礎となるコースに垂直切開を行います。 </li><li>大腿二頭筋と外側広筋の筋肉を露出させ、浅筋膜を通して切開を続けます。接続深い筋膜を切断することにより、これらの筋肉を分離します。 1〜2センチメートルカットが十分でなければなりません。 </li><li>上腕二頭筋を撤回共通腓骨神経を明らかにし、機械的なリトラクターを使って尾側筋肉大腿。 </li><li>そのインターまで近位に神経をトレース腓腹筋の外側頭の腱を持つセクションが発見されました。注：暴露は後退し、皮膚と筋肉の追加の操作が必要な場合があります。この交点は、神経損傷のための安定したランドマークとして使用されます。 </li><li>腓腹筋腱の外側縁に平行にヒントを合わせて、細かい鉗子で神経をつかみます。 5秒間安定し、ハード圧力を加えることにより、共通の腓骨神経をつぶします。 </li><li>外科手術用スコープを通して目視検査で神経の完全なクラッシュを裏付けます。これは、損傷部位で半透明表示されます。末梢軸索内の蛍光タンパク質を発現するマウスを使用している場合、蛍光が損傷部位から消えます。 </li><li>開創器を取り外し、その解剖学的位置に筋肉を再調整。 6-0絹縫合糸で切開部位を閉じます。 1-3単純結節縫合で十分です。クリーンケージ内の加熱パッド上療養マウスを置きます。 </li><li> 2時間後にオペラのためのすべての動物を監視しますションは、呼吸や麻酔への副作用をチェックします。すぐに手術からの回復次の皮下鼠径部の注射を介してブプレノルフィン0.05から0.10まで10mg / kgの初期用量を投与。 3追加の用量次の48時間にわたって12時間毎に与えます。完全に回復した後、動物のケア施設にマウスを返します。 </li></ol> 3.単離と染色伸展のDigitorum長い（EDL）筋肉<ol><li>イソフルランを使用して動物を生け贄に捧げます。吸収性labwipesを詰めた50ミリリットルチューブに0.5ミリリットルに液体イソフルランを分注します。密封された2500センチメートル3チャンバー内の動物でキャップされていないチューブを置きます。曝露の少なくとも4分で十分です。二国間の眼瞼、つま先のピンチ、およびテールピンチ反射の損失のための試験各動物は灌流を続行する前に、無意識であることを保証します。 </li><li>経最初の10mLの0.1M PBSで16匹の動物を灌流し、0.1M PBS（pH7.4）中の4％パラホルムアルデヒドを25ml。ヘパリン（30単位/ 20G動物の体重）の灌流の結果を向上させる、小さな毛細血管床に血液凝固を防ぐために、（10単位/ ml）のPBSを添加してもよいです。 </li><li>腹部の周囲の皮膚を通って横方向にカットするはさみを使用して、後肢を覆っている皮膚を取り除きます。ピンセットを用いて、後肢と足を過ぎて皮膚をピールダウン。 </li><li>把持鉗子で剥がして後肢の浅筋膜を削除します。末梢軸索内の蛍光タンパク質を発現するマウスを使用している場合は、50mlチューブに4％PFA中で一晩全体のマウスをポスト修正。 PBSで3回洗浄します。 注：固定したマウスは、4℃でPBS中に保存することができます。ない場合は、このステップをスキップし、定着後の動物せず3.6に進みます。 </li><li>できるだけ無傷の近位および遠位腱を維持することを確認され、マウス後肢からEDL筋18を解剖。 </li><li>少なくとも1時間、緩衝液（0.5％トリトンX-100を、3％BSAおよび5％ヤギ血清を含む1×PBS）でブロッキングEDL筋をインキュベートします。 </li><liシナプトタグミン-2（1：250）3日間ブロッキング緩衝液中に希釈した抗体：&gt;ニューロフィラメント（千1）を含有する試験管に運動軸索とその神経終末、場所の筋肉を可視化するために。筋肉を1×PBSで3回、10分毎の時間を洗ってください。注：末梢軸索内の蛍光タンパク質（XFP）を発現するマウスを使用している場合、この手順を省略してください。 </li><li>完全なNMJの神経支配のための陽性対照として、反対無傷EDLを染色します。陰性対照は、4日後の傷害、NMJが完全に除神経された時点で得られEDLだけでなく、二次抗体のみで染色したEDLを含める必要があります。 </li><li> 1日のニューロフィラメントおよびシナプトタグミン-2を検出するために、適切な蛍光タグ付けされた二次抗体を用いて筋肉をインキュベートします。筋肉を1×PBSで3回、10分毎の時間を洗ってください。注：このステップは、ステップ3.10と一緒に行うことができます。末梢軸索内の蛍光タンパク質を発現するマウスを使用している場合、この手順を省略してください。 </li><li> postsyを可視化するために、NMJのnaptic領域は、5μg/ mlの少なくとも2時間、ブロッキング緩衝液中に希釈したアレクサ555共役アルファ - ブンガロトキシンで筋肉をインキュベートします。筋肉を1×PBSで3回、10分毎の時間を洗ってください。 </li><li>正に荷電したガラススライド上に全体の筋肉をマウントするには、スライド上のメディアをマウントベースグリセロールの数滴を追加し、カバーガラスで覆い、スライド上に直接筋肉を置きます。筋肉を平らにするスライドに対してカバーガラスを押してください。実験用ワイプを使用してスライドとカバーガラスの周囲から取り付けメディアをオフに浸します。カバースリップとスライドの間のエッジをシールするためにマニキュアを適用します。 </li></ol> 4.イメージングとデータ解析<ol><li> NMJ、画像488、555および633 nmの光を励起し、20X及び40Xの目的で放出された光を捕捉するように装備共焦点レーザー走査顕微鏡を用いてEDL筋の構造を解析します。 </li><li>全体のNMJを視覚化するために、光秒の最大値投影画像を作成しますションは離れてNMJのに最高の可視領域の最下位から伸びる1〜2μmで間隔をあけ。市販のイメージングソフトウェアを使用して、最大強度の投影を作成します。 </li><li> 1）完全に除神経=シナプス後部位が軸索とAChRs間の軸索と接触し、5％未満の共局在を完全に欠いている：として神経再生の速度を決定するために、のNMJを分類。 2）部分的に神経支配=軸索は、部分的に軸索とAChRs間postsynapse 5〜95％の共局在と重なります。 3）全神経支配=前後シナプス間のほぼ完全な同格、軸索とAChRsの間、95％を超える共局在。撮像面に対して垂直に位置するか、完全に画像で視覚化されていないのNMJを除外します。注：すべてのこれらの実験では、少なくとも3匹の動物および動物あたり50のNMJを調べました。結果は、0.05未満のP値はスチューデントt検定を用いて有意とみなしました。 </li><li>演算子を盲目にするには、別々の個人が実行することができます手術および画像解析。治療群の知識がなくても、アナライザは、NMJの得点と客観することができます。代替的に、画像はランダム化原料動物の知識なしに分析のためにオペレータに提示することができます。 </li></ol> 5.定量PCR <ol><li>イソフルランと頸椎脱臼を使用して動物を生け贄に捧げます。皮膚とステップ3.3に応じて足の筋肉を覆う浅筋膜を削除します。 3.4段階に応じて前脛骨とEDL筋肉を解剖。 </li><li> Flashは、液体窒素に対する1.5mlチューブ全体の前脛骨とEDL筋肉を凍結します。部分的に液体窒素中に沈め予め冷却乳鉢でチューブと場所から組織を削除します。乳鉢と乳棒を用いて微粉末に凍結された筋肉を挽きます。 </li><li>市販のRNA抽出試薬に凍結筋肉粉末を溶解し、市販のキットを製造業者のIに従っててRNA抽出およびゲノムDNAの除去を行いますnstructions。 </li><li>製造元の説明書に従って市販の逆転写酵素ミ​​ックスを用いて逆転写を行います。 </li><li> （材料の表を参照）、適切なハウスキーピング遺伝子を用いて、市販のキットを用いて定量PCRを実行します。 （材料の表を参照）、PCRを実施するために、市販の定量的PCRサーマルサイクラーを使用してください。 </li><li> 58℃に設定し、アニール温度。 Taqポリメラーゼ/ SYBRグリーンミックスの製造業者の仕様書に追加のサイクリングパラメーターを調整します。プライマー特異性についてテストし、プライマーダイマー形成するために95℃まで65℃から0.5℃の増分増加からなるサーマルサイクラープログラムの最終融解曲線ステップを含みます。 </li><li>コントロール遺伝子として18S RNAを用いて、ΔΔCT法 21から2による相対mRNA発現レベルを決定します。 </li></ol>

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The authors have nothing to disclose.

この原稿に提示された方法は、神経筋接合部（NMJ）の修復に関与するメカニズムを識別するためのユニークな機会を提供しています。それは膝の近くに腓腹筋腱上を通過するように、この方法は、共通の腓骨神経を破砕することを含みます。私たちは、ピンセットで神経圧迫のわずか5秒後に、完全な変性は、損傷後4日までに指摘されていることを示しています。若い成体マウスでは、アル?...

In young adult and healthy animals, the neuromuscular junction (NMJ) is a highly stable connection between the presynapse, the nerve ending of an &#945;-motor axon, and the postsynapse, the specialized region of an extrafusal muscle fiber where nicotinic acetylcholine receptors (AChRs) selectively aggregate1. The nearly perfect apposition of the pre- and post-synaptic apparatuses is necessary for proper neurotransmission, survival of &#945;-motor neurons and muscle fibers and motor function. Unfortunately, the function of the NMJ is adversely affected by aging, diseases such as amyotrophic lateral sclerosis (ALS), autoimmune diseases and injury to muscles and peripheral nerves2-5. These insults often result in degeneration of presynaptic nerve endings, leaving muscles denervated and significantly altering motor skills. For this reason, the identification of molecules that function to maintain and repair the NMJ has become a priority. Because peripheral nerves regenerate and reinnervate targets, peripheral nerve injury models have been used to identify molecular changes associated with regenerating NMJs. 
Peripheral nerve injury models often involve either completely cutting or crushing specific nerve branches6. Following a cut, the endoneurial tube has to be reformed, delaying axonal regeneration and reinnervation of target cells and tissues. The severity of this type of injury also causes axons to meander away from their original path, resulting in their failure to reach original targets. This is in contrast to nerves injured via crush where the endoneurium remains contiguous, providing a path for efficient and proper regrowth of regenerating axons. It also allows axons to find and reinnervate their original muscle fiber partners. Irrespective of injury model, there are a number of cellular and molecular changes that must occur for axons to regenerate and reinnervate targets. After an injury, the nerve segment proximal to the target is broken down and removed via a process termed Wallerian Degeneration7. This process involves reprogramming and de-differentiation of Schwann cells into non-myelinating cells that secrete regenerative factors, clear myelin, and recruit macrophages to the site of injury8. Macrophages in turn complete the clearance of myelin and axonal debris, which would otherwise impede growth of the regenerating axon9. In parallel, motor and sensory neurons activate mechanisms needed to promote regeneration of their severed axons. Once the regenerating axon reaches the target, it must transform from a growth cone to a nerve ending capable of properly transmitting (for motor axons) or receiving (for sensory axons) information10. In this regard, alpha-motor axons undergo a series of well-orchestrated changes that culminate in their growth cone differentiating into a fully functional presynaptic nerve ending that nearly perfectly opposes the post-synaptic site on the target muscle fiber11. 
The sciatic, tibial and accessory nerves have been the primary choices for studying axonal and NMJ regeneration12-14. However, there are a number of drawbacks when using these models to examine cellular and molecular changes associated with regenerating NMJs between animals and under different conditions. Firstly, the sciatic nerve supplies the majority of the muscles of the hind limb, with injury significantly limiting both movement and sensation. It is therefore not possible to use this method to study the impact of exercise alone or in combination with other factors. Additionally, the sciatic nerve is a rather thick structure and thus requires a large amount of compressive force to fully injure all axons. This in turn may result in complete transection of the more superficial axons while leaving the endoneurial tube of deeper lying axons intact, introducing significant variability in the rate and fidelity of regeneration among these axons. Complete transection of this nerve is even less desirable given that many axons will fail to reconnect with the same muscle fibers. Complicating matters, the sciatic nerve possesses intrinsic anatomic variability, both in the number and site of origin of its terminal nerve branches. It is therefore very difficult to lesion the same site. While the tibial nerve is smaller and more amenable to crush injuries, there is also no readily available landmark to serve as a lesion site for this nerve branch. 
The accessory nerve branch (part of cranial nerve XI) that supplies the sternocleidomastoid muscle has also been used to study regeneration of NMJs15. This nerve is particularly attractive because NMJs in the sternocleidomastoid muscle can be more readily imaged in live animals compared to NMJs in other muscles. But similar to the sciatic and tibial nerves, there is no specific landmark that can be used to injure this nerve in the same location, limiting it as a model for comparing regeneration of NMJs among individual animals of an experimental cohort. An inconsistent lesion site introduces variability in the rates of NMJ reinnervation. Due to these shortcomings, the procedure presented here utilizes the injury of a different peripheral nerve branch to examine regenerating NMJs. 
The common fibular nerve, also called the common peroneal nerve, contains many features that make it a reliable nerve to examine regeneration of NMJs between animals and across different treatments. The common fibular nerve has a predictable anatomic course as it runs over the tendon of the lateral head of the gastrocnemius muscle in the knee, the intersection serving as a stable landmark for lesions. The nerve is accessed through a small and minimally invasive incision near but anatomically segregated from the muscles of interest. The findings presented here demonstrate that regenerating motor axons begin to reform NMJs in the extensor digitorum longus (EDL) muscle 8 days after crushing the fibular nerve in 70 days old young adult female mice. Importantly, the pattern and rate of reinnervation is consistent among animals of the same age and sex and therefore provide a reliable injury model that will significantly hasten our understanding of the cellular and molecular changes required to maintain and repair NMJs.

<table><tbody><tr><td>Ketamine</td><td>VetOne</td><td>501072</td><td></td></tr><tr><td>Xylazine</td><td>Lloyd Inc.&amp;nbsp;</td><td>003437&amp;nbsp;</td><td></td></tr><tr><td>Buprenorphine</td><td>&amp;nbsp;Zoopharm</td><td>1Z-73000-150910&amp;nbsp;</td><td></td></tr><tr><td>Nair</td><td>Nair</td><td></td><td></td></tr><tr><td>Kim-wipes</td><td>Kimtech</td><td>34155</td><td></td></tr><tr><td>Electric Razor</td><td>Braintree Scientific</td><td>CLP-64800</td><td></td></tr><tr><td>80% EtOH/H&lt;sub&gt;2&lt;/sub&gt;0</td><td></td><td></td><td></td></tr><tr><td>10% Proviodine</td><td></td><td></td><td></td></tr><tr><td>1 ml Insulin Syringe</td><td></td><td></td><td></td></tr><tr><td>Spring Scissors</td><td>Vannas</td><td>91500-09</td><td></td></tr><tr><td>No. 15 scalpel</td><td>Braintree Scientific</td><td>SSS 15</td><td></td></tr><tr><td>#5 Forceps</td><td>Dumont</td><td>11252-00</td><td></td></tr><tr><td>6-0 silk suture on reverse cutting needle</td><td>&amp;nbsp;Suture Express</td><td>752B&amp;nbsp;</td><td></td></tr><tr><td>Rodent Heating Pad</td><td>Braintree Scientific</td><td>AP-R-18.5</td><td></td></tr><tr><td>Alexa 555 conjugated alpha-BTX</td><td>Molecular Probes</td><td>B35451</td><td></td></tr><tr><td>Vectashield</td><td>Vector Labs</td><td>H-1000</td><td></td></tr><tr><td>Olympus Stereo Zoom Microscope</td><td>Olympus</td><td>562037192</td><td></td></tr><tr><td>Zeiss 700 Confocal Microscope</td><td>Zeiss</td><td></td><td></td></tr><tr><td>Variable-flow peristaltic perfusion pump</td><td>Fisher Scientific</td><td>13-876-3</td><td></td></tr><tr><td>Aurum Total RNA Mini Kit</td><td>Bio-Rad</td><td>7326820</td><td></td></tr><tr><td>Bio-Rad iScript RT Supermix</td><td>Bio-Rad</td><td>1708840</td><td></td></tr><tr><td>SsoFast Evagreen Supermix</td><td>Bio-Rad</td><td>1725200</td><td></td></tr><tr><td>Bio-Rad CFX96</td><td>Bio-Rad</td><td>1855196</td><td></td></tr><tr><td>Puralube Vet ointment</td><td>Puralube</td><td>1621</td><td></td></tr><tr><td>Synaptotagmin-2 antibody</td><td>Antibodies-Online</td><td>ABIN401605</td><td></td></tr><tr><td>Neurofilament antibody</td><td>Antibodies-Online</td><td>ABIN2475842</td><td></td></tr></tbody></table>

the fibular nerve injury method: a reliable assay to identify and test factors that repair neuromuscular junctions

神経筋接合部（NMJ）が加齢、損傷および疾患の結果として有害な構造的および機能的変化を受けます。したがって、のNMJの維持及び修復に関与する細胞および分子の変化を把握することが不可欠です。この目的のために、我々は、確実かつ一貫してマウスでのNMJの再生検査する方法を開発しました。それは膝の近くに腓腹筋腱の外側頭の上を通過するように、この神経損傷の方法は、共通の腓骨神経を破砕することを含みます。 70日齢の雌のマウスを使用して、我々は運動軸索がポストクラッシュ7日以内に、前シナプス後の標的を神経再支配し始めることを示しています。彼らは完全に12日までに、以前のシナプス領域を再占拠します。この傷害の方法の信頼性を決定するために、我々は個々の70日齢の雌マウスとの間神経再支配率を比較しました。我々はreinnervatedシナプス後サイトの数は7、9でマウスの間で類似していたことがわかった、と12日後にクラッシュ。かどうかを確認するにはこの傷害アッセイはまた、筋肉の分子の変化を比較するために使用することができ、我々は、筋肉ニコチン性受容体（γ-のAChR）および筋特異的キナーゼ（ムスク）のγサブユニットのレベルを調べました。ガンマのAChRサブユニットとムスクは非常に次の除神経をアップレギュレートし、のNMJの再神経支配次の通常のレベルに戻っているします。我々は、これらの遺伝子と筋肉の神経支配の状態のための転写レベルの間の密接な関係を発見しました。我々は、このメソッドはNMJや他のシナプスを修復に関与する細胞および分子変化の我々の理解を加速すると考えています。

共通腓骨神経は、また、総腓骨神経と呼ばれる、それは脚部（ 図1A）の前方側面に腓骨の頭の周りに揺動膝窩、上記の坐骨神経から生じます。そこに浅と深い腓骨神経に分岐し、一緒に（前脛骨筋、長指伸筋とブレビス、および伸筋halluces長い筋）足の背屈筋とつま先を供給し、足のeverters（腓骨筋）。この神経はまた、足の甲と足の下半分の外側面に突?...

Watch this Scientific Journal Video about The Fibular Nerve Injury Method: A Reliable Assay to Identify and Test Factors That Repair Neuromuscular Junctions at JoVE.com

The Fibular Nerve Injury Method: A Reliable Assay to Identify and Test Factors That Repair Neuromuscular Junctions

We have developed a nerve injury method to reliably examine muscle reinnervation, and thus regeneration of neuromuscular junctions in mice. This technique involves injuring the common fibular nerve via a simple and highly reproducible surgery. Muscle reinnervation in then assessed by whole-mounting the extensor digitorum longus muscle.

腓骨神経損傷方法：神経筋接合部を修復信頼性の高い同定するためのアッセイおよびテスト要因

The neuromuscular junction (NMJ) undergoes deleterious structural and functional changes as a result of aging, injury and disease. Thus, it is imperative ...

the-fibular-nerve-injury-method-reliable-assay-to-identify-test

Research

JoVE Journal

Neuroscience

15.6K ビュー.  Virginia Tech. We have developed a nerve injury method to reliably examine muscle reinnervation, and thus regeneration of neuromuscular junctions in mice. This technique involves injuring the common fibular nerve via a simple and highly reproducible surgery. Muscle reinnervation in then assessed by whole-mounting the extensor digitorum longus muscle. 

ビデオ: The Fibular Nerve Injury Method: A Reliable Assay to Identify and Test Factors That Repair Neuromuscular Junctions

Reproducible Mouse Sciatic Nerve Crush and Subsequent Assessment of Regeneration by Whole Mount Muscle Analysis

Regeneration in the peripheral nervous system (PNS) is widely studied both for its relevance to human disease and to understand the robust regenerative response mounted by PNS neurons thereby possibly illuminating the failures of CNS regeneration1. Sciatic nerve crush (axonotmesis) is one of the most common models of peripheral nerve injury in rodents2. Crushing interrupts all axons but Schwann cell basal laminae are preserved so that regeneration is optimal3,4. This allows the investigator to study precisely the ability of a growing axon to interact with both the Schwann cell and basal laminae4. Rats have generally been the preferred animal models for experimental nerve crush. They are widely available and their lesioned sciatic nerve provides a reasonable approximation of human nerve lesions5,4. Though smaller in size than rat nerve, the mouse nerve has many similar qualities. Most importantly though, mouse models are increasingly valuable because of the wide availability of transgenic lines now allows for a detailed dissection of the individual molecules critical for nerve regeneration6, 7. Prior investigators have used multiple methods to produce a nerve crush or injury including simple angled forceps, chilled forceps, hemostatic forceps, vascular clamps, and investigator-designed clamps8,9,10,11,12. Investigators have also used various methods of marking the injury site including suture, carbon particles and fluorescent beads13,14,1. We describe our method to obtain a reproducibly complete sciatic nerve crush with accurate and persistent marking of the crush-site using a fine hemostatic forceps and subsequent carbon crush-site marking. As part of our description of the sciatic nerve crush procedure we have also included a relatively simple method of muscle whole mount we use to subsequently quantify regeneration.

In this report we describe a method to crush mouse sciatic nerve. This method uses readily available hemostatic forceps and easily and reproducibly produces complete sciatic nerve crush. In addition, we describe a method to prepare muscle whole mounts suitable for analysis of nerve regeneration after sciatic nerve crush.

ホールマウントマッスル分析による再現性のあるマウスの坐骨神経クラッシュと再生のその後の評価

Regeneration in the peripheral nervous system (PNS) is widely studied both for its relevance to human disease and to understand the robust regenerative ...

神経科学

Applications of In Vivo Functional Testing of the Rat Tibialis Anterior for Evaluating Tissue Engineered Skeletal Muscle Repair

Despite the regenerative capacity of skeletal muscle, permanent functional and/or cosmetic deficits (e.g., volumetric muscle loss (VML) resulting from traumatic injury, disease and various congenital, genetic and acquired conditions are quite common. Tissue engineering and regenerative medicine technologies have enormous potential to provide a therapeutic solution. However, utilization of biologically relevant animal models in combination with longitudinal assessments of pertinent functional measures are critical to the development of improved regenerative therapeutics for treatment of VML-like injuries. In that regard, a commercial muscle lever system can be used to measure length, tension, force and velocity parameters in skeletal muscle. We used this system, in conjunction with a high power, bi-phase stimulator, to measure in vivo force production in response to activation of the anterior crural compartment of the rat hindlimb. We have previously used this equipment to assess the functional impact of VML injury on the tibialis anterior (TA) muscle, as well as the extent of functional recovery following treatment of the injured TA muscle with our tissue engineered muscle repair (TEMR) technology. For such studies, the left foot of an anaesthetized rat is securely anchored to a footplate linked to a servomotor, and the common peroneal nerve is stimulated by two percutaneous needle electrodes to elicit muscle contraction and dorsiflexion of the foot. The peroneal nerve stimulation-induced muscle contraction is measured over a range of stimulation frequencies (1-200 Hz), to ensure an eventual plateau in force production that allows for an accurate determination of peak tetanic force. In addition to evaluation of the extent of VML injury as well as the degree of functional recovery following treatment, this methodology can be easily applied to study diverse aspects of muscle physiology and pathophysiology. Such an approach should assist with the more rational development of improved therapeutics for muscle repair and regeneration.

Applications of In Vivo Functional Testing of the Rat Tibialis Anterior for Evaluating Tissue Engineered Skeletal Muscle Repair

We describe an in vivo protocol to measure dorsiflexion of the foot following stimulation of the peroneal nerve and contraction of the anterior crural compartment of the rat hindlimb. Such measurements are an indispensable translational tool for evaluating skeletal muscle pathology and tissue engineering approaches to muscle repair and regeneration.

の応用<em&gt;インビボ</em組織工学骨格筋の修復を評価するためのラット前脛骨の&gt;機能テスト

Despite the regenerative capacity of skeletal muscle, permanent functional and/or cosmetic deficits (e.g., volumetric muscle loss (VML) resulting from ...

生物工学

Assessment of Neuromuscular Function Using Percutaneous Electrical Nerve Stimulation

Percutaneous electrical nerve stimulation is a non-invasive method commonly used to evaluate neuromuscular function from brain to muscle (supra-spinal, spinal and peripheral levels). The present protocol describes how this method can be used to stimulate the posterior tibial nerve that activates plantar flexor muscles. Percutaneous electrical nerve stimulation consists of inducing an electrical stimulus to a motor nerve to evoke a muscular response. Direct (M-wave) and/or indirect (H-reflex) electrophysiological responses can be recorded at rest using surface electromyography. Mechanical (twitch torque) responses can be quantified with a force/torque ergometer. M-wave and twitch torque reflect neuromuscular transmission and excitation-contraction coupling, whereas H-reflex provides an index of spinal excitability. EMG activity and mechanical (superimposed twitch) responses can also be recorded during maximal voluntary contractions to evaluate voluntary activation level. Percutaneous nerve stimulation provides an assessment of neuromuscular function in humans, and is highly beneficial especially for studies evaluating neuromuscular plasticity following acute (fatigue) or chronic (training/detraining) exercise.

We present a protocol to assess changes in neuromuscular function. Percutaneous electrical nerve stimulation is a non-invasive method that evokes muscular responses. Electrophysiological and mechanical properties of these responses permit the evaluation of neuromuscular function from brain to muscle (supra-spinal, spinal and peripheral levels).

経皮的電気神経刺激を使用した神経筋機能の評価

Percutaneous electrical nerve stimulation is a non-invasive method commonly used to evaluate neuromuscular function from brain to muscle (supra-spinal, ...

Measuring Neuromuscular Junction Functionality

Neuromuscular junction (NMJ) functionality plays a pivotal role when studying diseases in which the communication between motor neuron and muscle is impaired, such as aging and amyotrophic lateral sclerosis (ALS). Here we describe an experimental protocol that can be used to measure NMJ functionality by combining two types of electrical stimulation: direct muscle membrane stimulation and the stimulation through the nerve. The comparison of the muscle response to these two different stimulations can help to define, at the functional level, potential alterations in the NMJ that lead to functional decline in muscle.
Ex vivo preparations are suited to well-controlled studies. Here we describe an intensive protocol to measure several parameters of muscle and NMJ functionality for the soleus-sciatic nerve preparation and for the diaphragm-phrenic nerve preparation. The protocol lasts approximately 60 min and is conducted uninterruptedly by means of a custom-made software that measures the twitch kinetics properties, the force-frequency relationship for both muscle and nerve stimulations, and two parameters specific to NMJ functionality, i.e. neurotransmission failure and intratetanic fatigue. This methodology was used to detect damages in soleus and diaphragm muscle-nerve preparations by using SOD1G93A transgenic mouse, an experimental model of ALS that ubiquitously overexpresses the mutant antioxidant enzyme superoxide dismutase 1 (SOD1).

A functional assessment of the neuromuscular junction (NMJ) can provide essential information on the communication between muscle and nerve. Here we describe a protocol to comprehensively evaluate both the NMJ and muscle functionality using two different muscle-nerve preparations, i.e. soleus-sciatic and diaphragm-phrenic.

神経筋接合部機能を測定

Neuromuscular junction (NMJ) functionality plays a pivotal role when studying diseases in which the communication between motor neuron and muscle is ...

Murine Flexor Tendon Injury and Repair Surgery

Tendon connects skeletal muscle and bone, facilitating movement of nearly the entire body. In the hand, flexor tendons (FTs) enable flexion of the fingers and general hand function. Injuries to the FTs are common, and satisfactory healing is often impaired due to excess scar tissue and adhesions between the tendon and surrounding tissue. However, little is known about the molecular and cellular components of FT repair. To that end, a murine model of FT repair that recapitulates many aspects of healing in humans, including impaired range of motion and decreased mechanical properties, has been developed and previously described. Here an in-depth demonstration of this surgical procedure is provided, involving transection and subsequent repair of the flexor digitorum longus (FDL) tendon in the murine hind paw.&#160;This technique can be used to conduct lineage analysis of different cell types, assess the effects of gene gain or loss-of-function, and to test the efficacy of pharmacological interventions in the healing process. However, there are two primary limitations to this model: i) the FDL tendon in the mid-portion of the murine hind paw, where the transection and repair occur, is not surrounded by a synovial sheath. Therefore this model does not account for the potential contribution of the sheath to the scar formation process. ii) To protect the integrity of the repair site, the FT is released at the myotendinous junction, decreasing the mechanical forces of the tendon, likely contributing to increased scar formation. Isolation of sufficient cells from the granulation tissue of the FT during the healing process for flow cytometric analysis has proved challenging; cytology centrifugation to concentrate these cells is an alternate method used, and allows for generation of cell preparations on which immunofluorescent labeling can be performed. With this method, quantification of cells or proteins of interest during FT healing becomes possible.

Flexor tendons in the hand are commonly injured, leading to impaired hand function. However, the scar-tissue healing response is not well characterized. A murine model of flexor tendon healing is demonstrated here. This model can enhance overall understanding of the healing process and assess therapeutic approaches to improve healing.

マウス屈筋腱損傷および修復手術

Tendon connects skeletal muscle and bone, facilitating movement of nearly the entire body. In the hand, flexor tendons (FTs) enable flexion of the fingers ...

医学

Functional and Physiological Methods of Evaluating Median Nerve Regeneration in the Rat

The main goal of this investigation is to show how to create and repair different types of median nerve (MN) lesions in the rat. Moreover, different methods of simulating postoperative physiotherapy are presented. Multiple standardized strategies are used to assess motor and sensory recovery using an MN model of peripheral nerve lesion and repair, thus permitting easy comparison of the results. Several options are included for providing a postoperative physiotherapy-like environment to rats that have undergone MN injuries. Finally, the paper provides a method to evaluate the recovery of the MN using several noninvasive tests (i.e., grasping test, pin prick test, ladder rung walking test, rope climbing test, and walking track analysis), and physiological measurements (infrared thermography, electroneuromyography, flexion strength evaluation, and flexor carpi radialis muscle weight determination). Hence, this model seems particularly appropriate to replicate a clinical scenario, facilitating extrapolation of results to the human species.
Although the sciatic nerve is the most studied nerve in peripheral nerve research, analysis of the rat MN presents various advantages. For example, there is a reduced incidence of joint contractures and automutilation of the affected limb in MN lesion studies. Furthermore, the MN is not covered by muscle masses, making its dissection easier than that of the sciatic nerve. In addition, MN recovery is observed sooner, because the MN is shorter than the sciatic nerve. Also, the MN has a parallel path to the ulnar nerve in the arm. Hence, the ulnar nerve can be easily used as the nerve graft for repairing MN injuries. Finally, the MN in rats is located in the forelimb, akin to the human upper limb; in humans, the upper limb is the site of most peripheral nerve lesions.

Presented is a protocol to produce different types of median nerve (MN) lesions and repair in the rat. Additionally, the protocol shows how to evaluate the functional recovery of the nerve using several noninvasive behavioral tests and physiological measurements.

ラットの神経再生の中央値を評価する機能と生理学的方法

The main goal of this investigation is to show how to create and repair different types of median nerve (MN) lesions in the rat. Moreover, different ...

Maximum Isometric Tetanic Force Measurement of the Tibialis Anterior Muscle in the Rat

Traumatic nerve injuries result in substantial functional loss and segmental nerve defects often necessitate the use of autologous interposition nerve grafts. Due to their limited availability and associated donor side morbidity, many studies in the field of nerve regeneration focus on alternative techniques to bridge a segmental nerve gap. In order to investigate the outcomes of surgical or pharmacological experimental treatment options, the rat sciatic nerve model is often used as a bioassay. There are a variety of outcome measurements used in rat models to determine the extent of nerve regeneration. The maximum output force of the target muscle remains the most relevant outcome for clinical translation of experimental therapies. Isometric force measurement of tetanic muscle contraction has previously been described as a reproducible and valid technique for evaluating motor recovery after nerve injury or repair in both rat and rabbit models. In this video, we will provide a step-by-step instruction of this invaluable procedure for assessment of functional recovery of the tibialis anterior muscle in a rat sciatic nerve defect model using optimized parameters. We will describe the necessary pre-surgical preparations in addition to the surgical approach and dissection of the common peroneal nerve and tibialis anterior muscle tendon. The isometric tetanic force measurement technique will be detailed. Determining the optimal muscle length and stimulus pulse frequency is explained and measuring the maximum tetanic muscle contraction is demonstrated.

Evaluation of motor recovery remains the benchmark outcome measure in experimental peripheral nerve studies. The isometric tetanic force measurement of the tibialis anterior muscle in the rat is an invaluable tool to assess functional outcomes after reconstruction of sciatic nerve defects. The methods and nuances are detailed in this article.

ラットにおける脛表筋前筋の最大等角体テタニック力測定

Traumatic nerve injuries result in substantial functional loss and segmental nerve defects often necessitate the use of autologous interposition nerve ...

Implantation and Control of Wireless, Battery-free Systems for Peripheral Nerve Interfacing

Peripheral nerve interfaces are frequently used in experimental neuroscience and regenerative medicine for a wide variety of applications. Such interfaces can be sensors, actuators, or both. Traditional methods of peripheral nerve interfacing must either tether to an external system or rely on battery power that limits the time frame for operation. With recent developments of wireless, battery-free, and fully implantable peripheral nerve interfaces, a new class of devices can offer capabilities that match or exceed those of their wired or battery-powered precursors. This paper describes methods to (i) surgically implant and (ii) wirelessly power and control this system in adult rats. The sciatic and phrenic nerve models were selected as examples to highlight the versatility of this approach. The paper shows how the peripheral nerve interface can evoke compound muscle action potentials (CMAPs), deliver a therapeutic electrical stimulation protocol, and incorporate a conduit for the repair of peripheral nerve injury. Such devices offer expanded treatment options for single-dose or repeated dose therapeutic stimulation and can be adapted to a variety of nerve locations.

This is a protocol for the surgical implantation and operation of a wirelessly powered interface for peripheral nerves. We demonstrate the utility of this approach with examples from nerve stimulators placed on either the rat sciatic or phrenic nerve.

末梢神経インターフェースのためのワイヤレス、バッテリーレスシステムの移植と制御

Peripheral nerve interfaces are frequently used in experimental neuroscience and regenerative medicine for a wide variety of applications. Such interfaces ...

Modified Spared Nerve Injury Surgery Model of Neuropathic Pain in Mice

Spared nerve injury (SNI) is an animal model that mimics the cardinal symptoms of peripheral nerve injury for studying the molecular and cellular mechanism of neuropathic pain in mice and rats. Currently, there are two types of SNI model, one to cut and ligate the common peroneal and the tibial nerves with intact sural nerve, which is defined as SNIs in this study, and another to cut and ligate the common peroneal and the sural nerves with intact tibial nerve, which is defined as SNIt in this study. Because the sural nerve is purely sensory whereas the tibial nerve contains both motor and sensory fibers, the SNIt model has much less motor deficit than the SNIs model. In the traditional SNIt mouse model, the common peroneal and the sural nerves are cut and ligated separately. Here a modified SNIt surgery method is described to damage both common peroneal and sural nerves with only one ligation and one cut with a shorter procedure time, which is easier to perform and reduces the potential risk of stretching the sciatic or tibial nerves, and produces similar mechanical hypersensitivity as the traditional SNIt model.

<meta charset="utf8"></head><body>マウスの神経因性疼痛の改良温存神経損傷手術モデル

The modified surgery is a simplified method for mouse or rat spared nerve injury model that requires only one ligation and one cut to injure both common peroneal and sural nerves.