우리는 박사 힐리오 살가도, 레 나타 Lataro와 마우로 드 올리베이라, 프로세스의 집합 기간 동안 관대 한 지원을 Ribeirão Preto, 상 파울로와 박사 벤 Janssen, 심혈관 연구소 마스 트리 히트, 마스 트리 히트 대학, 대학의 의과 대학 감사드립니다. 이 작업은 보안 데이터 커넥터에 FONDECYT 보조금 N ° 11090114에 의해 지원되었다

프로토콜은 Facultad 드 Medicina 임상 Alemana - Universidad 델 Desarrollo의 윤리위원회에 의해 승인되었습니다. I.는 Dobutamine 주입을 준비 <ol><li> 500 μg / ML의 dobutamine의 주식 솔루션을 취득하기 위해서는 불임 distillated 물 20 ML에 dobutamine의 10 MG를 해산. -20 ° C.에서 나누어지는 및 매장 이 솔루션은 3 개월 이상에서 사용할 수 있습니다. </li><li> 상온에서 dobutamine 재고 솔루션의 나누어지는을 해동. </li><li> dobutamine (μg / ML) = 체중 X 0.2 : 수식을 사용하여 계산 농도 dobutamine 작업 솔루션을 취득하기 위해서는 불임 0.9 % NaCl에서 dobutamine 재고 솔루션을 희석. </li><li> dobutamine 작업 솔루션 1 ML의 주사기 29Gx1 / 2 &quot;을 입력합니다. </li><li> 20cm PE-10 관에 주사기의 바늘을 삽입합니다. </li><li> 제조업체 지침에 따라 주입 펌프에 주사기를 조정합니다. </li><li> 단계에서 램프 주입을 설​​정6 단계에, 각 단계를위한 10 μl / 분 증가 형식 - 투 - 단계. </li></ol> II. 압력 센서를 준비 <ol><li> 적어도 15 분 동안 37 ° C에서 멸균 물에 신호 드리프트 잠수함 압력 센서를 최소화합니다. 그 수압은 압력 센서에 영향을 미치는 것을 방지하기 위해 이상 0.5 cm 깊이 카테터를 발라하지 마십시오. </li><li> 전자 25 100 mmHg에 압력 센서를 보정. 전기 입력 (볼트)는 압력 신호 (mmHg)로 변환된다. </li><li> 2 K / s의 샘플링 속도를 설정하고는 100 Hz에서 잘라와 필터 낮은 패스를 사용합니다. 압력 신호 제로 mmHg로 설정합니다. </li><li> 끝에서 카테터 15mm를 선택합니다. 소개 점에서 마음에 도달 할 먼은 왼쪽 ventricule에 카테 테르의 존재를 검출, echocardiography에 의해 추정되었다. </li></ol> III. Catheterization에 마우스를 준비 <ol><li> 무게 C57BL / 6 남자 마우스, 주 된 30-32. </li><li> intraperitoneally 60 μg / kg 케타민, 4 μg / kg xylazine 1 주사. 참고 : 다른 anesthetics 예를 들어, 사용할 수 있습니다 : 350-450 μg / kg avertin, 50 μg / kg pentobarbital 1.5 - 2퍼센트 isoflurane 2-3. </li><li> 전기 면도기로 목을 면도. </li><li> 예열 등온 가열 플레이트에 위로 향한 위치에 anesthetized 마우스를 놓습니다. 종이 테이프와의 사지를 고정합니다. </li><li> 완전한 진정 작용을 확인하기 위해 발가락 핀치을 수행합니다. </li><li> 부드럽게 체온을 모니터링하기 위해 직장 프로브를 삽입합니다. vaselinized 프로브를 사용하는 것이 좋습니다. </li><li> 몸의 온도가 37과 다른 경우 ° C ± 0.5 ° C, 가열 플레이트를 통해이를 조정할 수 있습니다. </li><li> 산소 공급 근처에 마우스 주둥이를 놔. </li><li> stereomicroscope에서 마우스 목 지역을 놓으십시오. </li></ol> IV. 데이터 수집 <ol><li> LabChartPro 7 소프트웨어에서 압력 등록 하나의 채널과 심장 박동을위한 하나의 채널 (HR)을 선택등록. 후자의 경우, 옵션 &quot;순환 측정&quot;와 속도 등의 설정 측정을 선택합니다. </li><li> 0-150 mmHg : 압력 채널에 대한 스케일 범위를 설정합니다. </li><li> 200-600 BPM : 들어 HR 채널은 규모의 범위를 설정합니다. </li><li> 등록을 시작하려면 시작 키를 누릅니다. </li><li> 절차 예를 들어, 수행 나타내는 코멘트를 삽입 마취 관리는 변경 사항을 호흡, dobutamine 주입, dobutamine 농도 시작합니다. </li></ol> V. 심장의 Catheterization 4,5 <ol><li> 턱 근처의 오른쪽에 작은 절개를 수행합니다. 가위는 피부 근육 결합 조직을 별도의. </li><li> 기관의 오른쪽에 - 세로 절개 (2cm 1.5) 수행합니다. 기관 근처의 오른쪽 경동맥을 노출하기 위해, 곡선 포셉과 결합 조직, 지방과 근육을 분리합니다. </li><li> 경동맥을 노출 할 수있는 동물 오른쪽에 확장기를 놓습니다. 맥이 뛰는심장에 의해 생성 된 압력은 동맥의 식별을 용이하게한다. 어두운 빨간색 목 정맥은 오른쪽에 있습니다. </li><li> 곡선 포셉과 인접 조직에서 동맥을 분리합니다. 흰색 스레드 유사 미주 신경은 동맥을 따라 자리 잡고 있습니다. </li><li> 6 / 0 실크 스레드와 &quot;를 더블&quot;의 20cm 조각을 잘라 버릴거야. </li><li> 왼쪽에서 오른쪽으로 동맥 아래의 &quot;더블&quot;스레드를 전달합니다. 별도의 종료를 얻기 위해, 스레드를 잘라. </li><li> 동맥 아래 삼분의 일 목록 (10cm)를 전달합니다. </li><li> 머리에 가까이에 배치 스레드에 꼭 매듭, 그리고 더 말초 스레드에서 느슨한 하나를 묶어주세요. </li><li> 중간 스레드에서 느슨한 매듭을 묶었하고, 종이 테이프로 가열 패드에 중간 스레드의 오른쪽 끝을 해결할 수 있습니다. </li><li> 멸균 0.9 % NaCl을 삽입하여 경동맥이 촉촉하세요. 면이 눈에 액체의 초과를 말린다. </li><li> hemostat 클램프와 낮은 스레드를 스트레칭. </li><li> P에 의해 hemostat의 가위의 위치를​​ 고정혈액의 흐름을 막다하기 위해, 복부의 피부를 인칭 위의 스레드를 스트레칭. 동맥 주위에 결합 조직이 제거되었는지 확인합니다. 동맥 혈액의 전체 수 및 펄스을 박탈해야합니다. 동맥의 토크 힘을 생산에서 스레드를 방지합니다. </li><li> Vannas 마이크로 가위로 동맥의 하단에 단면 닉합니다. 혈액 방울 흘됩니다. </li><li> 경동맥에 카테터를 삽입합니다. 전체 압력 센서를 도입해야합니다. 더 혈액 손실이 없습니다 있는지 확인합니다. </li><li> 부드럽게 장소에 카테 테르를 개최하기 위해 중간 스레드 매듭을 조정합니다. 너무 많이 압축하지 말고, 압력 센서는 매우 약한 것입니다. </li><li> 동물의 복부에서 hemostat 가위를 놓습니다. </li><li> 혈액 손실을 방지하기 위해 손으로 카테터를 잡고 중간 스레드를 누르십시오. 참고 : 동맥이 피를 가득해야합니다. </li><li> 녹화 압력 신호를 시작합니다. </li><li> 카테터 안에되면,동맥 압력 신호가 60-70 100-120 mmHg로 변동. 압력 신호의 모양은 그림 1.A. 주에 표시됩니다 : 당신이에 관심이 있다면 신호가 적어도 5 분 동안 안정적 경우,이 시점에서 당신은 동맥 압력를 기록 할 수 있습니다. HR 값은 기록 신호의 30 초의 간격을 고려 압력 파형에서 얻은되었습니다. 이 조사 목표에 따르면, HR 직접 측정을 위해 또한 ECG 방법을 사용할 수 있습니다. </li><li> 부드럽게 압력 신호 (그림 1.B)의 모양 변화를 관찰하기 위해 카테터를 밀어. 카테터가 왼쪽 심실 안에서되면, 압력 신호는 0 100-120 mmHg로 변동. 이 카테터를 밀어하기 어려운 경우, 두 손가락으로 동물의 가슴을 찔러. </li><li> 지속적인 호흡 속도, 체온, 마취 수준 및 압력 신호를 제어합니다. 그들 모두는 안정적으로 유지해야합니다. </li></ol> VI. Dobutamine의 주입 <ol><li&gt; 경정맥 정맥 cannulation위한 천공을 방지하기 위해, 정맥 주위를 벗기 지방 조직해야합니다. 정맥 폐색의 수술 절차는 경동맥에 표시되는 절차와 비슷합니다. </li><li> 정맥에 PE-10 관을 소개합니다. 그 혈액의 흐름을 확인하는 것은 뒤로 주사기 플런저를 이동 차단되지 않습니다. </li><li> Dobutamine 주입은 10 μl / 분으로 시작 60 μl / 분으로 마무리하는거야. 모든 단계에서 주입 요금은 2 분 6 유지됩니다. </li><li> 마지막 dobutamine 투여 후, 마취의 약물로 동물을 안락사시켜야. </li></ol> VII. 데이터 분석 <ol><li> 데이터 분석을 위해, 여러분의 흥미에 기록 된 데이터의 섹션을 선택합니다. 압력 신호가 안정적있는 시간 간격을 고려하십시오. </li><li> 혈압 모듈의 설정 아이콘을 선택합니다. 압력 신호의 선택된 유형을 나타냅니다. </li><li> 자동 LabChartPro 7 소프트웨어 디스플레이 말은, 최대그리고 HR에 대한 최소 값, 수축기 압력 (P 최대), 이완기 압력 (P 분), 최종 이완기 압력 (EDP), 최대 긍정적 인 압력 개발 (DP / dtmax) 및 최대 부정적인 압력 개발 (DP / DT 분). 또한, 심장 매개 변수는 압력 추적에 묘사 할 수 있습니다. </li></ol>

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	<li>Hart, C. Y., Burnett, J. C., Redfield, M. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+avertin+versus+xylazine-ketamine+anesthesia+on+cardiac+function+in+normal+mice.">Effects of avertin versus xylazine-ketamine anesthesia on cardiac function in normal mice.</a> Am. J. Physiol. Heart Circ. Physiol. 281, H1938-H1945 (2001).</li><li>Janssen, B. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+anesthetics+on+systemic+hemodynamics+in+mice.">Effects of anesthetics on systemic hemodynamics in mice.</a> Am. J. Physiol. Heart Circ. Physiol. 287, H1618-H1624 (2004).</li><li>Lorenz, J. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+practical+guide+to+evaluating+cardiovascular,+renal,+and+pulmonary+function+in+mice.">A practical guide to evaluating cardiovascular, renal, and pulmonary function in mice.</a> Am. J. Physiol. Regul. Integr. Comp. Physiol. 282, R1565-R1582 (2002).</li><li>Lorenz, J. N., Robbins, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measurement+of+intraventricular+pressure+and+cardiac+performance+in+the+intact+closed-chest+anesthetized+mouse.">Measurement of intraventricular pressure and cardiac performance in the intact closed-chest anesthetized mouse.</a> Am. J. Physiol. 272, H1137-H1146 (1997).</li><li>Nemoto, S., DeFreitas, G., Carabello, B. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardiac+catheterization+technique+in+a+closed-chest+murine+model.">Cardiac catheterization technique in a closed-chest murine model.</a> Contemp. Top. Lab Anim. Sci. 42, 34-38 (2003).</li><li>Daniels, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impaired+cardiac+functional+reserve+in+type+2+diabetic+db/db+mice+is+associated+with+metabolic,+but+not+structural,+remodelling.">Impaired cardiac functional reserve in type 2 diabetic db/db mice is associated with metabolic, but not structural, remodelling.</a> Acta Physiol. (Oxf). 200, 11-22 (2010).</li><li>De Celle, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Long-term+structural+and+functional+consequences+of+cardiac+ischaemia-reperfusion+injury+in+vivo+in+mice.">Long-term structural and functional consequences of cardiac ischaemia-reperfusion injury in vivo in mice.</a> Exp. Physiol. 89, 605-615 (2004).</li><li>Huntgeburth, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transforming+growth+factor+beta+oppositely+regulates+the+hypertrophic+and+contractile+response+to+beta-adrenergic+stimulation+in+the+heart.">Transforming growth factor beta oppositely regulates the hypertrophic and contractile response to beta-adrenergic stimulation in the heart.</a> PLoS One. 6, e26628 (2011).</li><li>Reddy, A. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardiac+function+in+young+and+old+Little+mice.">Cardiac function in young and old Little mice.</a> J. Gerontol. A. Biol. Sci. Med. Sci. 62, 1319-1325 (2007).</li><li>Christoffersen, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardiac+lipid+accumulation+associated+with+diastolic+dysfunction+in+obese+mice.">Cardiac lipid accumulation associated with diastolic dysfunction in obese mice.</a> Endocrinology. 144, 3483-3490 (2003).</li></ol>

관심 없음 충돌이 선언 없습니다.

dobutamine에 의해 유도와 심장 catheterization에 의해 모니터링 심장​​ 스트레스 테스트는 힘든 것입니다. 그럼에도 불구하고, 여기 프로토콜을 따르면 설명 및 교육의 짧은 시간, 그것은 하나의 실험 마지막 약 한 시간에서 6 hemodynamic 매개 변수를 평가 할 수 있습니다. 제시 여기에 프로토콜의 중요한 단계는 혈관의 cannulations입니다. 경동맥의 cannulation에 대해서는 수행 절개은 ?...

<table border="1"><tbody><tr><td></td><td></td><td></td><td> 시약 </td></tr><tr><td> PE-50/10 </td><td> 워너 악기 </td><td> 64-0752 </td><td></td></tr><tr><td> 실크 스레드 6 / 0 HR17 </td><td> Tagum </td><td> SN0713K </td><td></td></tr><tr><td> Xylacin 20 MG / ML </td><td> Laboratorio의 Centrovet </td><td></td><td></td></tr><tr><td> 케타민 100 MG / ML </td><td> 드래그 제약 </td><td></td><td></td></tr><tr><td> 나트륨 염화물 0.9 % </td><td> 연구소 샌더슨 SA </td><td></td><td></td></tr><tr><td> Dobutamine 하이드로 클로라이드 </td><td> 시그마 - 알드리치 </td><td> D0676 </td><td></td></tr><tr><td> 주사기 U-100 인슐린 29G X ½ &quot; </td><td> Terumo 의료 (주) </td><td></td><td></td></tr><tr><td> 마이크로 11.5 cm 스타일 7 해부 집게 </td><td> 로턴Medizintechnik </td><td> 09-0959 </td><td></td></tr><tr><td> Graefe 집게 CVD 0.7mm 7cm </td><td> 로턴 Medizintechnik </td><td> 62-0263 </td><td></td></tr><tr><td> 클램프 Dieffenbach 불독 망할 CIA의 STR 38mm </td><td> 로턴 Medizintechnik </td><td> 60-010 </td><td></td></tr><tr><td> Vannas 가위 8cm STR FH </td><td> 로턴 Medizintechnik </td><td> 63-1400 </td><td></td></tr><tr><td></td><td></td><td></td><td> 장비 </td></tr><tr><td> SPR-671 MiKro - 팁 압력 카테터 </td><td> 밀라 악기 </td><td> 840-6719 </td><td></td></tr><tr><td> PCU-2000 압력 제어 단위 </td><td> 밀라 악기 </td><td> 880-0129 </td><td></td></tr><tr><td> PowerLab 30분의 4 </td><td> ADinstruments PTY (주) </td><td> ML866 </td><td></td></tr><tr><td> LabChartPro 7 </td><td> ADinstruments PTY (주) </td><td> MLU260 / 7 </td><td></td></tr><tr><td> Legato200 주입 펌프 </td><td> KdScientific </td><td> KD-KDS210P </td><td></td></tr><tr><td> TCAT - 2LV 온도 컨트롤러와 등온 가열 플레이트 </td><td> PhysiTemp 악기 주식회사 </td><td></td><td></td></tr><tr><td> 의료 산소 공급 </td><td> Indura </td><td></td><td></td></tr><tr><td> 직장 프로브 </td><td> ADinstruments PTY (주) </td><td> MLT1404 </td><td></td></tr><tr><td> Trinocular 현미경, 축 조명 </td><td> LW 과학 </td><td> Z2B-TRI-ETNE, ILP-1502-LTS1, ILP-1502-DGGF </td><td></td></tr></tbody></table>

cardiac stress test induced by dobutamine and monitored by cardiac catheterization in mice

Dobutamine은 동맥 (β 2)로 표현 수용체에 비해 심장 (β 1)로 표현 수용체에 대한 높은 친화력이있는 β-아드레날린 작용제입니다. 체계적으로 관리 할 때, 심장 수요를 증가시킵니다. 따라서, dobutamine 가능성이 경색의 위험이 비정상적인 리듬이나 허혈성 영역을 unmasks. 심장 스트레스 테스트 중에 심장 기능의 모니터링은 ecocardiography 또는 심장 catheterization에 의해 수행 할 수 있습니다. 후자는 전자의 침입하지만, 더 정확하고 유익한 기술입니다. 심장 박동 (HR), 수축기 혈압, 이완기 압력, 최종 이완기 압력, 최대 긍정적 인 압력 : 심장 스트레스 테스트 dobutamine에 의해 유도 여기에 설명 된대로 성취 심장 catheterization에 의해 모니터링는 단일 실험, 다음 hemodynamic 매개 변수의 측정에 수 개발 (DP / dtmax) 및 최대 부정적인 보도우레 개발 (DP / DT 분), 기본 조건에서와 dobutamine의 증가 복용 이하. 예상했던대로, 정상 마우스에서 우리는 HR, DP / DT 맥스와 DP / DT 분의 dobutamine 복용 관련 증가를 관찰했다. 또한, 가장 높은 복용량에서 높은 지방 다이어트 유발 비만 마우스의 심장 보상 작용의 상실이 가면을했습니다 (12 NG / g / 분) 테스트.

동맥 압력 신호는 수축기 및 이완기 압력에 의해 정의됩니다. 압력 센서는 왼쪽 심실 내부에있는 경우, 그 압력 (LVP)이 파형은 이완기 압력의 영에 드롭하고 심실 수축하기 전에 왼쪽 심방 수축 (그림 1)의 모습이 특징입니다. 기본 상태에서 케타민-xylazine anesthetized 일반 마우스는 280 HR ± 24, 107의 P 최대 ± 8, 5 P 분 ± 1, 14 EDP ± 2, DP / 6081의 DT 최대 ± 365 및 DP / DT <s...

Watch this Scientific Journal Video about Cardiac Stress Test Induced by Dobutamine and Monitored by Cardiac Catheterization in Mice at JoVE.com

Cardiac Stress Test Induced by Dobutamine and Monitored by Cardiac Catheterization in Mice

우리는 dobutamine에 의해 유도 및 일반 마우스의 심장 catheterization에 의해 모니터링 심장​​ 스트레스 테스트를 수행 할 수있는 프로토콜을 설명합니다. 또한 높은 지방 다이어트 유발 비만 마우스에 subclinical 심장 질환 가면을 벗어 라하기위한 응용 프로그램을 보여줍니다.

심장 스트레스 테스트 Dobutamine에 의해 유도와 마우스의 심장 Catheterization에 의해 모니터링

Dobutamine is a &beta;-adrenergic agonist with an affinity higher for receptor expressed in the heart (&beta;1) than for receptors expressed in the ...

cardiac-stress-test-induced-dobutamine-monitored-cardiac

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17.9K 조회수.  Clínica Alemana Universidad del Desarrollo. 우리는 dobutamine에 의해 유도 및 일반 마우스의 심장 catheterization에 의해 모니터링 심장​​ 스트레스 테스트를 수행 할 수있는 프로토콜을 설명합니다. 또한 높은 지방 다이어트 유발 비만 마우스에 subclinical 심장 질환 가면을 벗어 라하기위한 응용 프로그램을 보여줍니다.

비디오: Cardiac Stress Test Induced by Dobutamine and Monitored by Cardiac Catheterization in Mice

Assessment of Right Ventricular Structure and Function in Mouse Model of Pulmonary Artery Constriction by Transthoracic Echocardiography

Emerging clinical data support the notion that RV dysfunction is critical to the pathogenesis of cardiovascular disease and heart failure1-3. Moreover, the RV is significantly affected in pulmonary diseases such as pulmonary artery hypertension (PAH). In addition, the RV is remarkably sensitive to cardiac pathologies, including left ventricular (LV) dysfunction, valvular disease or RV infarction4. To understand the role of RV in the pathogenesis of cardiac diseases, a reliable and noninvasive method to access the RV structurally and functionally is essential.
A noninvasive trans-thoracic echocardiography (TTE) based methodology was established and validated for monitoring dynamic changes in RV structure and function in adult mice. To impose RV stress, we employed a surgical model of pulmonary artery constriction (PAC) and measured the RV response over a 7-day period using a high-frequency ultrasound microimaging system. Sham operated mice were used as controls. Images were acquired in lightly anesthetized mice at baseline (before surgery), day 0 (immediately post-surgery), day 3, and day 7 (post-surgery). Data was analyzed offline using software.
Several acoustic windows (B, M, and Color Doppler modes), which can be consistently obtained in mice, allowed for reliable and reproducible measurement of RV structure (including RV wall thickness, end-diastolic&#160;and end-systolic dimensions), and function (fractional area change, fractional shortening, PA peak velocity, and peak pressure gradient) in normal mice and following PAC.
Using this method, the pressure-gradient resulting from PAC was accurately measured in real-time using Color Doppler mode and was comparable to direct pressure measurements performed with a Millar high-fidelity microtip catheter. Taken together, these data demonstrate that RV measurements obtained from various complimentary views using echocardiography are reliable, reproducible and can provide insights regarding RV structure and function. This method will enable a better understanding of the role of RV cardiac dysfunction.

Right ventricle (RV) dysfunction is critical to the pathogenesis of cardiovascular disease, yet limited methodologies are available for its evaluation. Recent advances in ultrasound imaging provide a noninvasive and accurate option for longitudinal RV study. Herein, we detail a step-by-step echocardiographic method using a murine model of RV pressure overload.

경 흉부 심 초음파에 의한 폐동맥 수축의 마우스 모델에서 마우스 오른쪽 심실 구조 및 기능의 평가

Emerging clinical data support the notion that RV dysfunction is critical to the pathogenesis of cardiovascular disease and heart failure1-3. Moreover, ...

연구

의학

A Method to Study the Impact of Chemically-induced Ovarian Failure on Exercise Capacity and Cardiac Adaptation in Mice

The risk of cardiovascular disease (CVD) increases in post-menopausal women, yet, the role of exercise, as a preventative measure for CVD risk in post-menopausal women has not been adequately studied. Accordingly, we investigated the impact of voluntary cage-wheel exercise and forced treadmill exercise on cardiac adaptation in menopausal mice. The most commonly used inducible model for mimicking menopause in women is the ovariectomized (OVX) rodent. However, the OVX model has a few dissimilarities from menopause in humans. In this study, we administered 4-vinylcyclohexene diepoxide (VCD) to female mice, which accelerates ovarian failure as an alternative menopause model to study the impact of exercise in menopausal mice. VCD selectively accelerates the loss of primary and primordial follicles resulting in an endocrine state that closely mimics the natural progression from pre- to peri- to post-menopause in humans. To determine the impact of exercise on exercise capacity and cardiac adaptation in VCD-treated female mice, two methods were used. First, we exposed a group of VCD-treated and untreated mice to a voluntary cage wheel. Second, we used forced treadmill exercise to determine exercise capacity in a separate group VCD-treated and untreated mice measured as a tolerance to exercise intensity and endurance.

Two exercise paradigms were tested on a newly developed chemically induced menopausal mouse model to examine the impact of menopause on exercise capacity and cardiac adaption to exercise.

쥐의 운동 능력과 심장 적응에 화학적으로 유도 된 난소 실패의 영향을 연구하는 방법

The risk of cardiovascular disease (CVD) increases in post-menopausal women, yet, the role of exercise, as a preventative measure for CVD risk in ...

Early Detection of Drug-Induced Renal Hemodynamic Dysfunction Using Sonographic Technology in Rats

The kidney normally functions to maintain hemodynamic homeostasis and is a major site of damage caused by drug toxicity. Drug-induced nephrotoxicity is estimated to contribute to 19- 25% of all clinical cases of acute kidney injury (AKI) in critically ill patients. AKI detection has historically relied on metrics such as serum creatinine (sCr) or blood urea nitrogen (BUN) which are demonstrably inadequate in full assessment of nephrotoxicity in the early phase of renal dysfunction. Currently, there is no robust diagnostic method to accurately detect hemodynamic alteration in the early phase of AKI while such alterations might actually precede the rise in serum biomarker levels. Such early detection can help clinicians make an accurate diagnosis and help in in decision making for therapeutic strategy. Rats were treated with Cisplatin to induce AKI. Nephrotoxicity was assessed for six days using high-frequency sonography, sCr measurement and upon histopathology of kidney. Hemodynamic evaluation using 2D and Color-Doppler images were used to serially study nephrotoxicity in rats, using the sonography. Our data showed successful drug-induced kidney injury in adult rats by histological examination. Color-Doppler based sonographic assessment of AKI indicated that resistive-index (RI) and pulsatile-index (PI) were increased in the treatment group; and peak-systolic velocity (mm/s), end-diastolic velocity (mm/s) and velocity-time integral (VTI, mm) were decreased in renal arteries in the same group. Importantly, these hemodynamic changes evaluated by sonography preceded the rise of sCr levels. Sonography-based indices such as RI or PI can thus be useful predictive markers of declining renal function in rodents. From our sonography-based observations in the kidneys of rats that underwent AKI, we showed that these noninvasive hemodynamic measurements may consider as an accurate, sensitive and robust method in detecting early stage kidney dysfunction. This study also underscores the importance of ethical issues associated with animal use in research.

Early stage hemodynamic dysfunction is critical to the development of kidney disease. Yet, detection methodologies are limited. Recent advances in sonography provide a noninvasive, accurate option for early detection of kidney injury. This study outlines a step-by-step, sonographic methodology for detecting kidney dysfunction using a drug-induced nephrotoxicity rat model.

쥐에서 초음파 기술을 사용하여 약물 유발 신장 혈역학 적 부전의 조기 발견

The kidney normally functions to maintain hemodynamic homeostasis and is a major site of damage caused by drug toxicity. Drug-induced nephrotoxicity is ...

Cardiac Catheterization in Mice to Measure the Pressure Volume Relationship: Investigating the Bowditch Effect

Animal models that mimic human cardiac disorders have been created to test potential therapeutic strategies. A key component to evaluating these strategies is to examine their effects on heart function. There are several techniques to measure in vivo cardiac mechanics (e.g., echocardiography, pressure/volume relations, etc.). Compared to echocardiography, real-time left ventricular (LV) pressure/volume analysis via catheterization is more precise and insightful in assessing LV function. Additionally, LV pressure/volume analysis provides the ability to instantaneously record changes during manipulations of contractility (e.g., &#946;-adrenergic stimulation) and pathological insults (e.g., ischemia/reperfusion injury). In addition to the maximum (+dP/dt) and minimum (-dP/dt) rate of pressure change in the LV, an accurate assessment of LV function via several load-independent indexes (e.g., end systolic pressure volume relationship and preload recruitable stroke work) can be attained. Heart rate has a significant effect on LV contractility such that an increase in the heart rate is the primary mechanism to increase cardiac output (i.e., Bowditch effect). Thus, when comparing hemodynamics between experimental groups, it is necessary to have similar heart rates. Furthermore, a hallmark of many cardiomyopathy models is a decrease in contractile reserve (i.e., decreased Bowditch effect). Consequently, vital information can be obtained by determining the effects of increasing heart rate on contractility. Our and others data has demonstrated that the neuronal nitric oxide synthase (NOS1) knockout mouse has decreased contractility. Here we describe the procedure of measuring LV pressure/volume with increasing heart rates using the NOS1 knockout mouse model.

This article describes the measurement of murine left ventricular function via pressure/volume analysis at different heart rates.

Bowditch 효과 조사 : 압력 볼륨 관계를 측정하기 위해 마우스의 심장 도관

Animal models that mimic human cardiac disorders have been created to test potential therapeutic strategies. A key component to evaluating these ...

Myocardial Infarction in Neonatal Mice, A Model of Cardiac Regeneration

Myocardial infarction induced by coronary artery ligation has been used in many animal models as a tool to study the mechanisms of cardiac repair and regeneration, and to define new targets for therapeutics. For decades, models of complete heart regeneration existed in amphibians and fish, but a mammalian counterpart was not available. The recent discovery of a postnatal window during which mice possess regenerative capabilities has led to the establishment of a mammalian model of cardiac regeneration. A surgical model of mammalian cardiac regeneration in the neonatal mouse is presented herein. Briefly, postnatal day 1 (P1) mice are anesthetized by isoflurane and placed on an ice pad to induce hypothermia. After the chest is opened, and the left anterior descending coronary artery (LAD) is visualized, a suture is placed around the LAD to inflict myocardial ischemia in the left ventricle. The surgical procedure takes 10-15 min. Visualizing the coronary artery is crucial for accurate suture placement and reproducibility. Myocardial infarction and cardiac dysfunction are confirmed by triphenyl-tetrazolium chloride (TTC) staining and echocardiography, respectively. Complete regeneration 21 days post myocardial infarction is verified by histology. This protocol can be used to as a tool to elucidate mechanisms of mammalian cardiac regeneration after myocardial infarction.

This protocol describes a highly reproducible model of cardiac regeneration by surgical induction of myocardial infarction in the left ventricle of postnatal day 1 mice. The method involves induction of hypothermic anesthesia and ligation of the left anterior descending coronary artery.

신생아 쥐의 심근 경색, 심장 재생의 모델

Myocardial infarction induced by coronary artery ligation has been used in many animal models as a tool to study the mechanisms of cardiac repair and ...

A Model of Glaucoma Induced by Circumlimbal Suture in Rats and Mice

The circumlimbal suture is a technique for inducing experimental glaucoma in rodents by chronically elevating intraocular pressure (IOP), a well-known risk factor for glaucoma. This protocol demonstrates a step-by-step guide on this technique in Long Evans rats and C57BL/6 mice. Under general anesthesia, a "purse-string" suture is applied on the conjunctiva, around the equator and behind the limbus of the eye. The fellow eye serves as an untreated control. Over the duration of our study, which was a period of 8 weeks for rats and 12 weeks for mice, IOP remained elevated, as measured regularly by rebound tonometry in conscious animals without topical anesthesia. In both species, the sutured eyes showed electroretinogram features consistent with preferential inner retinal dysfunction. Optical coherence tomography showed selective thinning of the retinal nerve fiber layer. Histology of the rat retina in cross-section found reduced cell density in the ganglion cell layer, but no change in other cellular layers. Staining of flat-mounted mouse retinae with a ganglion cell specific marker (RBPMS) confirmed ganglion cell loss. The circumlimbal suture is a simple, minimally invasive and cost-effective way to induce ocular hypertension that leads to ganglion cell injury in both rats and mice.

Chronic ocular hypertension is induced by applying a circumlimbal suture in rats and mice, leading to functional and structural deterioration of the retinal ganglion cells consistent with glaucoma.

쥐와 쥐에 Circumlimbal 봉합에 의해 유도 된 녹 내장의 모델

The circumlimbal suture is a technique for inducing experimental glaucoma in rodents by chronically elevating intraocular pressure (IOP), a well-known ...

Isolation of Atrial Myocytes from Adult Mice

The electrophysiological properties of atrial myocytes importantly affect overall cardiac function. Alterations in the underlying ionic currents responsible for the action potential can cause pro-arrhythmic substrates that underlie arrhythmias, such as atrial fibrillation, which are highly prevalent in many conditions and disease states. Isolating adult mouse atrial cardiomyocytes for use in patch-clamp experiments has greatly advanced our knowledge and understanding of the cellular electrophysiology in the healthy atrial myocardium and in the setting of atrial pathophysiology. In addition, studies using genetic mouse models have elucidated the role of a vast array of proteins in regulating atrial electrophysiology. Here we provide a detailed protocol for the isolation of cardiomyocytes from the atrial appendages of adult mice using a combination of enzymatic digestion and mechanical dissociation of these tissues. This approach consistently and reliably yields isolated atrial cardiomyocytes that can then be used to characterize cellular electrophysiology by measuring action potentials and ionic currents in patch-clamp experiments under a number of experimental conditions.

This protocol is used to isolate single atrial cardiomyocytes from the adult mouse heart using a chunk digestion approach. This approach is used to isolate right or left atrial myocytes that can be used to characterize atrial myocyte electrophysiology in patch-clamp studies.

성인 마우스에서 심방 근세포의 격리

The electrophysiological properties of atrial myocytes importantly affect overall cardiac function. Alterations in the underlying ionic currents ...

Biventricular Assessment of Cardiac Function and Pressure-Volume Loops by Closed-Chest Catheterization in Mice

Assessment of cardiac function is essential to conduct cardiovascular and pulmonary-vascular preclinical research. Pressure-volume loops (PV loops) generated by recording both pressure and volume during cardiac catheterization are vital when assessing both systolic and diastolic cardiac function. Left and right heart function are closely related, reflected in ventricular interdependence. Thus, recording biventricular function in the same animal is important to get a complete assessment of cardiac function. In this protocol, a closed chest approach to cardiac catheterization consistent with the way catheterization is performed in patients is adopted in mice. While challenging, the closed chest strategy is a more physiological approach, because opening the chest results in major changes in preload and afterload that create artifacts, most notably a fall in systemic blood pressure. While high-resolution echocardiography is used to assess rodents, cardiac catheterization is invaluable, particularly when assessing diastolic pressures in both ventricles.
Described here is a procedure to perform invasive, closed chest, sequential left and right ventricular pressure-volume (PV) loops in the same animal. PV loops are acquired using&#160;admittance technology with a mouse pressure-volume catheter and pressure-volume system acquisition. The procedure is described, beginning with the neck dissection, which is required to access the right jugular vein and the right carotid artery, to the insertion and positioning of the catheter, and finally the data acquisition. Then, the criteria required to ensure the acquisition of high-quality PV loops are discussed. Finally, the analysis of the left and right ventricular PV loops and the different hemodynamic parameters available to quantify systolic and diastolic ventricular function are briefly described.

Presented here is a protocol to assess biventricular heart function in mice by generating pressure-volume (PV) loops from the right and left ventricle in the same animal using closed chest catheterization. The focus is on the technical aspect of surgery and data acquisition.

생쥐의 폐쇄 흉부 카테터 삽입에 의한 심장 기능 및 압력-부피 루프의 양심실 평가

Assessment of cardiac function is essential to conduct cardiovascular and pulmonary-vascular preclinical research. Pressure-volume loops (PV loops) ...

A Large Animal Model for Acute Kidney Injury by Temporary Bilateral Renal Artery Occlusion

Acute kidney injury (AKI) is associated with higher risk for morbidity and mortality post-operatively. Ischemia-reperfusion injury (IRI) is the most common cause of AKI. To mimic this clinical scenario, this study presents a highly reproducible large animal model of renal IRI in swine using temporary percutaneous bilateral balloon-catheter occlusion of the renal arteries. The renal arteries are occluded for 60 min by introducing the balloon-catheters through the femoral and carotid artery and advancing them into the proximal portion of the arteries. Iodinated contrast is injected in the aorta to assess any opacification of the kidney vessels and confirm the success of the artery occlusion. This is furtherly confirmed by the flattening of the pulse waveform at the tip of the balloon catheters. The balloons are deflated and removed after 60 min of bilateral renal artery occlusion, and the animals are allowed to recover for 24 h. At the end of the study, plasma creatinine and blood urea nitrogen significantly increase, while eGFR and urine output significantly decrease. The need for iodinated contrast is minimal and does not affect renal function. Bilateral renal artery occlusion better mimics the clinical scenario of perioperative renal hypoperfusion, and the percutaneous approach minimizes the impact of the inflammatory response and the risk of infection seen with an open approach, such as a laparotomy. The ability to create and reproduce this clinically relevant swine model eases the clinical translation to humans.

This study presents a highly reproducible large animal model of renal ischemia-reperfusion injury in swine using temporary percutaneous bilateral balloon-catheter occlusion of the renal arteries for 60 min and reperfusion for 24 h.

일시적인 양측 신장 동맥 폐색에 의한 급성 신장 손상에 대한 대형 동물 모델

Acute kidney injury (AKI) is associated with higher risk for morbidity and mortality post-operatively. Ischemia-reperfusion injury (IRI) is the most ...

Advanced Cardiac Rhythm Management by Applying Optogenetic Multi-Site Photostimulation in Murine Hearts

Ventricular tachyarrhythmias are a major cause of mortality and morbidity worldwide. Electrical defibrillation using high-energy electric shocks is currently the only treatment for life-threatening ventricular fibrillation. However, defibrillation may have side-effects, including intolerable pain, tissue damage, and worsening of prognosis, indicating a significant medical need for the development of more gentle cardiac rhythm management strategies. Besides energy-reducing electrical approaches, cardiac optogenetics was introduced as a powerful tool to influence cardiac activity using light-sensitive membrane ion channels and light pulses. In the present study, a robust and valid method for successful photostimulation of Langendorff perfused intact murine hearts will be described based on multi-site pacing applying a 3 x 3 array of micro light-emitting diodes (micro-LED). Simultaneous optical mapping of epicardial membrane voltage waves allows the investigation of the effects of region-specific stimulation and evaluates the newly induced cardiac activity directly on-site. The obtained results show that the efficacy of defibrillation is strongly dependent on the parameters chosen for photostimulation during a cardiac arrhythmia. It will be demonstrated that the illuminated area of the heart plays a crucial role for termination success as well as how the targeted control of cardiac activity during illumination for modifying arrhythmia patterns can be achieved. In summary, this technique provides a possibility to optimize the on-site mechanism manipulation on the way to real-time feedback control of cardiac rhythm and, regarding the region specificity, new approaches in reducing the potential harm to the cardiac system compared to the usage of non-specific electrical shock applications.

This work reports a method for controlling the cardiac rhythm of intact murine hearts of transgenic channelrhodopsin-2 (ChR2) mice using local photostimulation with a micro-LED array and simultaneous optical mapping of epicardial membrane potential.

쥐 심장에 광유전학적 다중 부위 광자극을 적용하여 고급 심장 리듬 관리

Ventricular tachyarrhythmias are a major cause of mortality and morbidity worldwide. Electrical defibrillation using high-energy electric shocks is ...