우리는 근육의 생체내 관찰에 그의 조언 JW Lichtman 감사합니다.

RBC 막 염색법 <ol><li> 마우스 붉은 혈액 세포 heparinization과 같은 마우스 변형에서 수정되었습니다. </li><li> 마우스 RBC는 PKH26 염료 (; 레드 형광 세포 링커 키트, 시그마, 미국 567분​​의 551 NM)와 스테인드되었습니다. </li><li> RBC는 PBS로 씻어하고 실온에서 5 분 PKH26 염료의 2μM 솔루션 incubated되었습니다. 반응은 플라즈마를 추가 (열 65 ° C 사전에서 1 시간 동안 inactivated)과 1 분 incubated에 의해 중지되었습니다. </li><li> 스테인드 RBC는 PBS로 5 번 씻어했다. </li></ol> 마우스 준비 <ol><li> 3 ~ 6 달이 넘은 남성 C57BL/10 생쥐는이 연구에 사용되었다. 우리 pentobarbital의 intraperitoneal 주입 (50mg/kgBW)에 의해 anesthetized 마우스. </li><li> 생쥐는 다음 20 게이지 폴리에틸렌 튜브로 intubated 기계적 환기, 그리고 37 기까지했다 ° 열전대 센서와 피드백 온도 컨트롤러 시스템에 연결된 Kapton 시트 히터에 C. </li><li> 목 복부 측면을 면도했다. 좌우 sternomastoid 근육이 노출되었습니다. 근육은 스테인레스 스틸 홀더 지원 및 살균 크렙스 링어 솔루션 superfused되었습니다. </li></ol> 주사 <ol><li> 스테인드 RBCs는 37 크렙스 링어에 희석 ° C에서 예열했다. 스테인드 RBC (혈소판 12 %)의 50ul는 성기 정맥에서 마우스에 주입했다. </li></ol> 골격 근육의 생체내 미세 전망대에서 우리는 수정 1 제프 W. Lichtman의 방법을 따라 : <ol><li> 동물은 니콘 이클립스 - 800 현미경의 손으로 만들어진 철 무대 위에 가열 패드에 배치했다. 물 수영 객관 렌즈는 라이브 에피 형광 관찰하기 위해 이용되었다. 우리는 머큐리 램프의 형광 불빛 아래에서 혈관의 PKH26 스테인드 RBC 흐르는 내부를 관찰했다. 우리가 그들의 RBCs 흐름 방향과 구조에 의해 기본 arterioles, 보조 arterioles, 모세 혈관과 정맥을 확인. </li><li> 강화 SIT 카메라 (하마 마츠 Photonics, C240​​0, 일본)와 비디오 프레임 그래버는 실시간 비디오 속도 (초당 30 프레임)에서 낮은 강도의 신호를 캡처하기 위해 설치되었다. 이미지가 비디오 파일로 DVD에 기록되었다. </li></ol> 근육 자극 <ol><li> 전기 펄스는 주변 신경 자극기 (Innervator 252, 피셔 &amp; 페이켈 건강, 뉴질랜드)을 사용하여 생성하고, 코팅 스테인레스 프로브를 통해 근육의 표면에 전달했다. 마이너스 프로브 끝을 근육의 근위 부분에 배치되었고 플러스 끝을 근육의 말초 부분에 배치되었습니다. 파상풍 stimulations은 5 초 동안 50Hz의 속도로 제공되었습니다. 전기 자극은 접촉 영역의 주변에 직접 myofiber 손상을 일으키지 않았다. </li></ol> RBC 플럭스 분석 <ol><li> 기록 DVD 비디오 이미지는 프레임 그래버 소프트웨어 (비디오 사반트, 미국)를 통해 비디오 사반트 이미지 파일을 전송했다. 비디오 이미지는 각각의 스테인드 RBC을 시각화하기 위해 조정 속도가 검토되었다. RBC 플럭스은 분당 초점을 기본 arteriole 날아 RBC를 계산하여 측정되었다. </li></ol>

<ol>
	<li>Lichtman, J. W., Magrassi, L., Purves, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visualization+of+neuromuscular+junctions+over+periods+of+several+months+in+living+mice.">Visualization of neuromuscular junctions over periods of several months in living mice.</a> J Neurosci. 7, 1215-1222 (1987).</li></ol>

동물 실험에 관한 모든 절차는 매사 추세츠 종합 병원의 연구 애니멀 케어에있는 분과의 검토와 승인되었습니다.

중요 techinical 포인트는 다음과 같다 : (1) 관찰을위한 생리 동물의 상태 (perfusative 솔루션, 체온의 환기, 산도), 스테인드 RBC (2) 사출 볼륨, 그리고 (3) 조건의 유지 보수 (최적 렌즈 선택, 형광 강도). 향후 응용 프로그램은 다음과 같습니다 pharmacophysiological 및 / 또는 분자 생물 학적 개입과 (A) 조합, arterio / arteriolo - 경화증과 neovascularization의 (B) 장기 관찰.

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<td>PKH26 dye </td>
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<td>551/567 nm; Red fluorescent cell linker kit</td>
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<td>C57BL/10 mice </td>
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<td>pentobarbital </td>
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in vivo micro-circulation measurement in skeletal muscle by intra-vital microscopy

배경 : 규제 요인 및 생체내의 엑기스에 대한 자세한 생리가 남아있어 완전히 이미지가 발명했다 다양한 modalities 후 명확히하지 않습니다. 혈액 흐름의 많은 매크로 매개 변수는 유속, 혈액 흐름 속도와 적혈구 세포 (RBC)의 변화를 반영하는 동안 흐름은 현미경 관찰에 선형 관계를 보유하지 않습니다. RBC 속도와 RBC 플럭스, RBC 자속 및 플라즈마 흐름 볼륨 사이에, 그리고 현미경 관찰, 사용 microcirculatory 규정에 자세한 연구의 요구에 대해 과학적 근거에 주변 조직의 흐름을 규제의 공간 및 시간적 이질의 차이가보고있다 intravital 현미경. 방법 : 우리는 마우스 sternomastoid 근육의 생체내 미세 관찰의 제프 Lichtman의 방법을 수정했습니다. 마우스가 anesthetized 있으며, 환기, 그리고 현미경 관찰을위한 PKH26L - 찬란 분류 RBCs 주사. 결과 및 결론 : 찬란 분류 RBCs가 감지하고 넓은 분야 현미경으로 잘 구분할 수 있습니다. 근육 수축은 RBC 유동적 전기 자극을 유발 증가 evoked. RBC의 속도와 모세관 밀도 등 다른 매개 변수의 부량이 가능했다. 마우스는 잘 수술, 스테인드 RBCs의 주입, 현미경 관찰, 전기 자극을 용납. 아무도 근육이나 혈관 손상은 우리의 방법은 상대적으로 덜 침습 장기 관찰에 적합 것을 제안, 관찰되지 않았습니다.

Watch this Scientific Journal Video about In vivo Micro-circulation Measurement in Skeletal Muscle by Intra-vital Microscopy at JoVE.com

In vivo Micro-circulation Measurement in Skeletal Muscle by Intra-vital Microscopy

엑기스의 관찰을위한 새로운 다양한 방법을 제시합니다. 이것은 장기 관찰에 적합 간주하고, pharmacophysiological 또는 분자 생물 학적 중재와 함께입니다.

내부 핵심 현미경에 의해 골격근의 생체내 미세 순환 측정

BACKGROUND: Regulatory factors and detailed physiology of in vivo microcirculation have remained not fully clarified after many different modalities of ...

in-vivo-micro-circulation-measurement-skeletal-muscle-intra-vital

Research

JoVE Journal

Biology

11.1K 조회수.  Massachusetts General Hospital, and Harvard Medical School. 엑기스의 관찰을위한 새로운 다양한 방법을 제시합니다. 이것은 장기 관찰에 적합 간주하고, pharmacophysiological 또는 분자 생물 학적 중재와 함께입니다.

비디오: In vivo Micro-circulation Measurement in Skeletal Muscle by Intra-vital Microscopy

Tracking Dynamics of Muscle Engraftment in Small Animals by In Vivo Fluorescent Imaging

Muscular dystrophies are a group of degenerative muscle diseases characterized by progressive loss of contractile muscle cells. Currently, there is no curative treatment available. Recent advances in stem cell biology have generated new hopes for the development of effective cell based therapies to treat these diseases. Transplantation of various types of stem cells labeled with fluorescent proteins into muscles of dystrophic animal models has been used broadly in the field. A non-invasive technique with the capability to track the transplanted cell fate longitudinally can further our ability to evaluate muscle engraftment by transplanted cells more accurately and efficiently.
In the present study, we demonstrate that in vivo fluorescence imaging is a sensitive and reliable method for tracking transplanted GFP (Green Fluorescent Protein)-labeled cells in mouse skeletal muscles. Despite the concern about background due to the use of an external light necessary for excitation of fluorescent protein, we found that by using either nude mouse or eliminating hair with hair removal reagents much of this problem is eliminated. Using a CCD camera, the fluorescent signal can be detected in the tibialis anterior (TA) muscle after injection of 5 x 105 cells from either GFP transgenic mice or eGFP transduced myoblast culture. For more superficial muscles such as the extensor digitorum longus (EDL), injection of fewer cells produces a detectable signal. Signal intensity can be measured and quantified as the number of emitted photons per second in a region of interest (ROI). Since the acquired images show clear boundaries demarcating the engrafted area, the size of the ROI can be measured as well. If the legs are positioned consistently every time, the changes in total number of photons per second per muscle and the size of the ROI reflect the changes in the number of engrafted cells and the size of the engrafted area. Therefore the changes in the same muscle over time are quantifiable. In vivo fluorescent imaging technique has been used primarily to track the growth of tumorogenic cells, our study shows that it is a powerful tool that enables us to track the fate of transplanted stem cells.

Tracking Dynamics of Muscle Engraftment in Small Animals by In Vivo Fluorescent Imaging

We describe an in vivo fluorescence imaging protocol to monitor muscle regeneration by GFP-labeled myoblasts after transplantation into skeletal muscles of both healthy and dystrophic mice. This protocol can be adapted to study muscle regeneration by transplantation of other types of cells and in other muscular conditions as well.

작은 동물의 근육 Engraftment의 역학에 의해 추적 VIVO에서 형광 이미징

Muscular dystrophies are a group of degenerative muscle diseases characterized by progressive loss of contractile muscle cells. Currently, there is no ...

연구

생물학

Fluorescence-based Measurement of Store-operated Calcium Entry in Live Cells: from Cultured Cancer Cell to Skeletal Muscle Fiber

Store operated Ca2+ entry (SOCE), earlier termed capacitative Ca2+ entry, is a tightly regulated mechanism for influx of extracellular Ca2+ into cells to replenish depleted endoplasmic reticulum (ER) or sarcoplasmic reticulum (SR) Ca2+ stores1,2. Since Ca2+ is a ubiquitous second messenger, it is not surprising to see that SOCE plays important roles in a variety of cellular processes, including proliferation, apoptosis, gene transcription and motility. Due to its wide occurrence in nearly all cell types, including epithelial cells and skeletal muscles, this pathway has received great interest3,4. However, the heterogeneity of SOCE characteristics in different cell types and the physiological function are still not clear5-7.
The functional channel properties of SOCE can be revealed by patch-clamp studies, whereas a large body of knowledge about this pathway has been gained by fluorescence-based intracellular Ca2+ measurements because of its convenience and feasibility for high-throughput screening. The objective of this report is to summarize a few fluorescence-based methods to measure the activation of SOCE in monolayer cells, suspended cells and muscle fibers5,8-10. The most commonly used of these fluorescence methods is to directly monitor the dynamics of intracellular Ca2+ using the ratio of F340nm and F380nm (510 nm for emission wavelength) of the ratiometric Ca2+ indicator Fura-2. To isolate the activity of unidirectional SOCE from intracellular Ca2+ release and Ca2+ extrusion, a Mn2+ quenching assay is frequently used. Mn2+ is known to be able to permeate into cells via SOCE while it is impervious to the surface membrane extrusion processes or to ER uptake by Ca2+ pumps due to its very high affinity with Fura-2. As a result, the quenching of Fura-2 fluorescence induced by the entry of extracellular Mn2+ into the cells represents a measurement of activity of SOCE9. Ratiometric measurement and the Mn+2 quenching assays can be performed on a cuvette-based spectrofluorometer in a cell population mode or in a microscope-based system to visualize single cells. The advantage of single cell measurements is that individual cells subjected to gene manipulations can be selected using GFP or RFP reporters, allowing studies in genetically modified or mutated cells. The spatiotemporal characteristics of SOCE in structurally specialized skeletal muscle can be achieved in skinned muscle fibers by simultaneously monitoring the fluorescence of two low affinity Ca2+ indicators targeted to specific compartments of the muscle fiber, such as Fluo-5N in the SR and Rhod-5N in the transverse tubules9,11,12.

The extent of store-operated Ca2+ entry (SOCE) can be monitored using fluorescent Ca2+ indicators. Mn2+ quenching of such indicators assays SOCE in cultured cells and skeletal muscle fibers. A technique allowing spatial and temporal resolution of SOCE by confocal imaging of mechanically skinned muscle fibers is also described.

라이브 세포의 저장소로 작동하는 칼슘 항목의 형광 기반의 측정 : 교양 암 세포에서 골격근 섬유에

Store operated Ca2+ entry (SOCE), earlier termed capacitative Ca2+ entry, is a tightly regulated mechanism for influx of extracellular Ca2+ into cells to ...

Ex Vivo Assessment of Contractility, Fatigability and Alternans in Isolated Skeletal Muscles

Described here is a method to measure contractility of isolated skeletal muscles. Parameters such as muscle force, muscle power, contractile kinetics, fatigability, and recovery after fatigue can be obtained to assess specific aspects of the excitation-contraction coupling (ECC) process such as excitability, contractile machinery and Ca2+ handling ability. This method removes the nerve and blood supply and focuses on the isolated skeletal muscle itself. We routinely use this method to identify genetic components that alter the contractile property of skeletal muscle though modulating Ca2+ signaling pathways. Here, we describe a newly identified skeletal muscle phenotype, i.e., mechanic alternans, as an example of the various and rich information that can be obtained using the in vitro muscle contractility assay. Combination of this assay with single cell assays, genetic approaches and biochemistry assays can provide important insights into the mechanisms of ECC in skeletal muscle.

Ex Vivo Assessment of Contractility, Fatigability and Alternans in Isolated Skeletal Muscles

We describe a method to directly measure muscle force, muscle power, contractile kinetics and fatigability of isolated skeletal muscles in an in vitro system using field stimulation. Valuable information on Ca2+ handling properties and contractile machinery of the muscle can be obtained using different stimulating protocols.

절연 골격근의 수축성, Fatigability 및 Alternans의 예 VIVO 평가

 
Described here is a method to measure contractility of isolated skeletal muscles. Parameters such as muscle force, muscle power, contractile kinetics, ...

Assessment of Calcium Sparks in Intact Skeletal Muscle Fibers

Maintaining homeostatic Ca2+ signaling is a fundamental physiological process in living cells. Ca2+ sparks are the elementary units of Ca2+ signaling in the striated muscle fibers that appear as highly localized Ca2+ release events mediated by ryanodine receptor (RyR) Ca2+ release channels on the sarcoplasmic reticulum (SR) membrane. Proper assessment of muscle Ca2+ sparks could provide information on the intracellular Ca2+&#160;handling properties of healthy and diseased striated muscles. Although Ca2+ sparks events are commonly seen in resting cardiomyocytes, they are rarely observed in resting skeletal muscle fibers; thus there is a need for methods to generate and analyze sparks in skeletal muscle fibers.
Detailed here is an experimental protocol for measuring Ca2+ sparks in isolated flexor digitorm brevis (FDB) muscle fibers using fluorescent Ca2+ indictors and laser scanning confocal microscopy. In this approach, isolated FDB fibers are exposed to transient hypoosmotic stress followed by a return to isotonic physiological solution. Under these conditions, a robust Ca2+ sparks response is detected adjacent to the sarcolemmal membrane in young healthy FDB muscle fibers. Altered Ca2+ sparks response is detected in dystrophic or aged skeletal muscle fibers. This approach has recently demonstrated that membrane-delimited signaling involving cross-talk between inositol (1,4,5)-triphosphate receptor (IP3R) and RyR contributes to Ca2+ spark activation in skeletal muscle. In summary, our studies using osmotic stress induced Ca2+ sparks showed that this intracellular response reflects a muscle signaling mechanism in physiology and aging/disease states, including mouse models of muscle dystrophy (mdx mice) or amyotrophic lateral sclerosis (ALS model).

Described here is a method to directly measure calcium sparks, the elementary units of Ca2+ release from sarcoplasmic reticulum&#160;in intact skeletal muscle fibers. This method utilizes osmotic-stress-mediated triggering of Ca2+ release from ryanodine receptor in isolated muscle fibers. The dynamics and homeostatic capacity of intracellular Ca2+ signaling can be employed to assess muscle function in health and disease.

칼슘의 평가는 그대로 골격 근육 섬유에서 불꽃

Maintaining homeostatic Ca2+ signaling is a fundamental physiological process in living cells. Ca2+ sparks are the elementary units of Ca2+ signaling in ...

In vivo Clonal Tracking of Hematopoietic Stem and Progenitor Cells Marked by Five Fluorescent Proteins using Confocal and Multiphoton Microscopy

We developed and validated a fluorescent marking methodology for clonal tracking of hematopoietic stem and progenitor cells (HSPCs) with high spatial and temporal resolution to study in vivo hematopoiesis using the murine bone marrow transplant experimental model. Genetic combinatorial marking using lentiviral vectors encoding fluorescent proteins (FPs) enabled cell fate mapping through advanced microscopy imaging. Vectors encoding five different FPs: Cerulean, EGFP, Venus, tdTomato, and mCherry were used to concurrently transduce HSPCs, creating a diverse palette of color marked cells. Imaging using confocal/two-photon hybrid microscopy enables simultaneous high resolution assessment of uniquely marked cells and their progeny in conjunction with structural components of the tissues. Volumetric analyses over large areas reveal that spectrally coded HSPC-derived cells can be detected non-invasively in various intact tissues, including the bone marrow (BM), for extensive periods of time following transplantation. Live studies combining video-rate multiphoton and confocal time-lapse imaging in 4D demonstrate the possibility of dynamic cellular and clonal tracking in a quantitative manner.

In vivo Clonal Tracking of Hematopoietic Stem and Progenitor Cells Marked by Five Fluorescent Proteins using Confocal and Multiphoton Microscopy

Combinatorial 5 fluorescent proteins marking of hematopoietic stem and progenitor cells allows in vivo clonal tracking via confocal and two-photon microscopy, providing insights into bone marrow hematopoietic architecture during regeneration. This method allows non-invasive fate mapping of spectrally-coded HSPCs-derived cells in intact tissues for extensive periods of time following transplantation.

공 초점 및 다중 광자 현미경을 사용하여 다섯 형광 단백질에 의해 표시됨 조혈 줄기 및 전구 세포의 생체 내 클론 추적에서

We developed and validated a fluorescent marking methodology for clonal tracking of hematopoietic stem and progenitor cells (HSPCs) with high spatial and ...

In Vivo 4-Dimensional Tracking of Hematopoietic Stem and Progenitor Cells in Adult Mouse Calvarial Bone Marrow

Through a delicate balance between quiescence and proliferation, self renewal and production of differentiated progeny, hematopoietic stem cells (HSCs) maintain the turnover of all mature blood cell lineages. The coordination of the complex signals leading to specific HSC fates relies upon the interaction between HSCs and the intricate bone marrow microenvironment, which is still poorly understood[1-2].
We describe how by combining a newly developed specimen holder for stable animal positioning with multi-step confocal and two-photon in vivo imaging techniques, it is possible to obtain high-resolution 3D stacks containing HSPCs and their surrounding niches and to monitor them over time through multi-point time-lapse imaging. High definition imaging allows detecting ex vivo labeled hematopoietic stem and progenitor cells (HSPCs) residing within the bone marrow. Moreover, multi-point time-lapse 3D imaging, obtained with faster acquisition settings, provides accurate information about HSPC movement and the reciprocal interactions between HSPCs and stroma cells.
Tracking of HSPCs in relation to GFP positive osteoblastic cells is shown as an exemplary application of this method. This technique can be utilized to track any appropriately labeled hematopoietic or stromal cell of interest within the mouse calvarium bone marrow space.

In Vivo 4-Dimensional Tracking of Hematopoietic Stem and Progenitor Cells in Adult Mouse Calvarial Bone Marrow

The nature of the interactions between hematopoietic stem and progenitor cells (HSPCs) and bone marrow niches is poorly understood. Custom hardware modifications and a multi-step acquisition protocol allow the use of two-photon and confocal microscopy to image ex vivo labeled HSPCs homed within bone marrow areas, tracking interactions and movement.

성인 마우스 두개골 골수에서 조혈 줄기 및 전구 세포의 생체 내 4 차원 추적에서

Through a delicate balance between quiescence and proliferation, self renewal and production of differentiated progeny, hematopoietic stem cells (HSCs) ...

Measurement of Microtubule Dynamics by Spinning Disk Microscopy in Monopolar Mitotic Spindles

We describe a modification of an established method to determine microtubule dynamics in living cells. The protocol is based on the expression of a genetically encoded marker for the positive ends of microtubules (EB3 labelled with tdTomato fluorescent protein) and high-speed, high-resolution, live-cell imaging using spinning disk confocal microscopy. Cell cycle synchronization and increased density of microtubules are achieved by inhibiting centrosomal separation in mitotic cells, and analysis of growth is performed using open-source U-Track software. The use of a bright and red-shifted fluorescent protein, in combination with the lower laser power and reduced exposure time required for spinning disk microscopy reduce phototoxicity and the probability of light-induced artifacts. This allows for imaging a larger number of cells in the same preparation while maintaining the cells in a growth medium under standard culture conditions. Because the analysis is performed in a supervised automatic fashion, the results are statistically robust and reproducible.

Here we present a robust and detailed method of microtubule dynamics analysis in cells synchronized in prometaphase using live-cell spinning disk confocal microscopy and MATLAB-based image processing.

단극성 미토틱 스핀들에서 디스크 현미경 검사법에 의한 미세소관 역학 측정

We describe a modification of an established method to determine microtubule dynamics in living cells. The protocol is based on the expression of a ...

Measurement of Insulin- and Contraction-Stimulated Glucose Uptake in Isolated and Incubated Mature Skeletal Muscle from Mice

Skeletal muscle is an insulin-responsive tissue and typically takes up most of the glucose that enters the blood after a meal. Moreover, it has been reported that skeletal muscle may increase the extraction of glucose from the blood by up to 50-fold during exercise compared to resting conditions. The increase in muscle glucose uptake during exercise and insulin stimulation is dependent on the translocation of glucose transporter 4 (GLUT4) from intracellular compartments to the muscle cell surface membrane, as well as phosphorylation of glucose to glucose-6-phosphate by hexokinase II. Isolation and incubation of mouse muscles such as m. soleus and m. extensor digitorum longus (EDL) is an appropriate ex vivo model to study the effects of insulin and electrically-induced contraction (a model for exercise) on glucose uptake in mature skeletal muscle. Thus, the ex vivo model permits evaluation of muscle insulin sensitivity and makes it possible to match muscle force production during contraction ensuring uniform recruitment of muscle fibers during measurements of muscle glucose uptake. Moreover, the described model is suitable for pharmacological compound testing that may have an impact on muscle insulin sensitivity or may be of help when trying to delineate the regulatory complexity of skeletal muscle glucose uptake.
Here we describe and provide a detailed protocol on how to measure insulin- and contraction-stimulated glucose uptake in isolated and incubated soleus and EDL muscle preparations from mice using radiolabeled [3H]2-deoxy-D-glucose and [14C]mannitol as an extracellular marker. This allows accurate assessment of glucose uptake in mature skeletal muscle in the absence of confounding factors that may interfere in the intact animal model. In addition, we provide information on metabolic viability of incubated mouse skeletal muscle suggesting that the method&#160;applied possesses some caveats under certain conditions when studying muscle energy metabolism.

Intact regulation of muscle glucose uptake is important for maintaining whole body glucose homeostasis. This protocol presents assessment of insulin- and contraction-stimulated glucose uptake in isolated and incubated mature skeletal muscle when delineating the impact of various physiological interventions on whole body glucose metabolism.

마우스로부터 단리되고 배양된 성숙한 골격근에서의 인슐린- 및 수축-자극된 글루코스 흡수의 측정

Skeletal muscle is an insulin-responsive tissue and typically takes up most of the glucose that enters the blood after a meal. Moreover, it has been ...

In vivo Measurement of Knee Extensor Muscle Function in Mice

Skeletal muscle plasticity in response to countless conditions and stimuli mediates concurrent functional adaptation, both negative and positive. In the clinic and the research laboratory, maximal muscular strength is widely measured longitudinally in humans, with knee extensor musculature the most reported functional outcome. Pathology of the knee extensor muscle complex is well documented in aging, orthopedic injury, disease, and disuse; knee extensor strength is closely related to functional capacity and injury risk, underscoring the importance of reliable measurement of knee extensor strength. Repeatable, in vivo assessment of knee extensor strength in pre-clinical rodent studies offers valuable functional endpoints for studies exploring osteoarthritis or knee injury. We report an in vivo and non-invasive protocol to repeatedly measure isometric peak tetanic torque of the knee extensors in mice across time. We demonstrate consistency using this novel method to measure knee extensor strength with repeated assessment in multiple mice producing similar results.

Quantification of knee extensor maximal strength is imperative to understand functional adaptations to aging, disease, injury, and rehabilitation. We present a novel method to repeatedly measure in vivo knee extension isometric peak tetanic torque.

마우스에서 무릎 엑스텐서 근육 기능의 생체 측정

Skeletal muscle plasticity in response to countless conditions and stimuli mediates concurrent functional adaptation, both negative and positive. In the ...

탈세포화(decellularization)를 통한 골격근 지방 침투의 정량화

Decellularization-Based Quantification of Skeletal Muscle Fatty Infiltration

Fatty infiltration is the accumulation of adipocytes between myofibers in skeletal muscle and is a prominent feature of many myopathies, metabolic disorders, and dystrophies. Clinically in human populations, fatty infiltration is assessed using noninvasive methods, including computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound (US). Although some studies have used CT or MRI to quantify fatty infiltration in mouse muscle, costs and insufficient spatial resolution remain challenging. Other small animal methods utilize histology to visualize individual adipocytes; however, this methodology suffers from sampling bias in heterogeneous pathology. This protocol describes the methodology to qualitatively view and quantitatively measure fatty infiltration comprehensively throughout intact mouse muscle and at the level of individual adipocytes using decellularization. The protocol is not limited to specific muscles or specific species and can be extended to human biopsy. Additionally, gross qualitative and quantitative assessments can be made with standard laboratory equipment for little cost, making this procedure more accessible across research laboratories.

저자 스포트라이트: 골격근 지방 침투의 탈세포화 기반 정량화  

The present study describes decellularization-based methodologies for visualizing and quantifying intramuscular adipose tissue (IMAT) deposition through intact muscle volume, as well as quantifying metrics of individual adipocytes that comprise IMAT.