마우스의 다발성 경화증의 EAE 모델에서 시신경염 및 뇌 염증의 생물 발광 및 근적외선 영상
Summary
우리는 생체 살아있는 생물 발광 및 근적외선 SJL / J 마우스에서 다발성 경화증에 대한 실험자가 면역 뇌척수염 (EAE) 모델에서 시신경염과 뇌염의 이미징 기술을 보여준다.
Abstract
SJL / J 쥐에 실험자가 면역 뇌척수염 (EAE)는 재발 – 완화 성 다발성 경화증 (RRMS)의 모델이다. 운동 기능 적자를 설명하는 임상 EAE 점수는 척수의 면역 매개 염증의 기본 판독입니다. 그러나 점수와 체중은 뇌의 염증과 시신경염의 생체 내 평가를 허용하지 않습니다. 후자는 2/3 MS 환자에서 초기 자주 표현된다. 여기서는 생체 촬상 시스템을 이용하여 살아있는 쥐 생물 발광과 EAE는 시신경염을 유발 평가 근적외선 라이브 영상, 뇌 염증 및 혈액 – 뇌 장벽 (BBB) 중단하는 방법을 보여준다. 산화 효소에 의해 활성화 생물 발광 기판은 주로 시신경염 나타났다. 신호는 특정이었고, 임상 점수를 병렬 약물 효과 및 질병 시간 과정의 시각화를 허용했다. vasculatur 내에 남아 페 길화 된 형광 나노 입자장시간 E는 BBB의 무결성을 평가하기 위해 사용되었다. 근적외선 영상은 질병의 피크에서 BBB 누수를 한 것으로 밝혀졌습니다. 신호는 눈 주위 강했다. 매트릭스 메탈 용 근적외선 기판 EAE – 유발 된 염증을 평가하기 위해 사용되었다. 자동 형광 정량 unmixing 스펙트럼을 요구 신호 간섭. 전반적으로, 생물 발광 이미징 EAE 관련 시신경염 약물 효과를 평가하기위한 신뢰성있는 방법이고 신호 특이성 견고성 정량의 용이성 및 비용면에서 근적외선 기술보다 우수 하였다.
Introduction
Multiple sclerosis is caused by the autoimmune-mediated attack and destruction of the myelin sheath in the brain and the spinal cord1. With an overall incidence of about 3.6 cases per 100,000 people a year in women and about 2.0 in men, MS is the second most common cause of neurological disability in young adults, after traumatic injuries2,3. The disease pathology is contributed to by genetic and environmental factors4 but is still not completely understood. Autoreactive T lymphocytes enter the central nervous system and trigger an inflammatory cascade that causes focal infiltrates in the white matter of the brain, spinal cord, and optic nerve. In most cases, these infiltrates are initially reversible, but persistence increases with the number of relapses. A number of rodent models have been developed to study the pathology of the disease. The relapsing-remitting EAE in SJL/J mice and the primary-progressive EAE in C57BL6 mice are the most popular models.
The clinical EAE scores, which describe the extent of the motor function deficits, and body weight are the gold standards to assess EAE severity. These clinical signs agree with the extent of immune cell infiltration and myelin destruction in the spinal cord and moderately predict drug treatment efficacy in humans5. However, these signs mainly reflect the destruction of the ventral fiber tracts in the spinal cord. Presently, there is no easy, non-invasive, reliable, and reproducible method to assess in vivo brain infiltration and optic neuritis in living mice.
The in vivo imaging agrees with the 3 “R” principles of Russel and Burch (1959), which claim a Replacement, Reduction, and Refinement of animal experiments6, because imaging increases the readouts of one animal at several time points and allows for a reduction of the overall numbers. Presently, inflammation or myelin status is mainly assessed ex vivo via immunohistochemistry, FACS-analysis, or different molecular biological methods7, all requiring euthanized mice at specific time points.
A number of in vivo imaging system probes have been developed to assess inflammation in the skin, joints, and vascular system. The techniques rely on the activation of bioluminescent or near-infrared fluorescent substrates by tissue peroxidases, including myeloperoxidase (MPO), matrix metalloproteinases (MMPs)8, and cathepsins9 or cyclooxygenase2. These probes have been mainly validated in models of arthritis or atherosclerosis9,10. A cathepsin-sensitive probe has also been used for fluorescence molecular tomographic imaging of EAE11. MMPs, particularly MMP2 and MMP9, contribute to the protease-mediated BBB disruption in EAE and are upregulated at sites of immune cell infiltration12, suggesting that these probes may be useful for EAE imaging. The same holds true for peroxidase or cathepsin-based probes. Technically, imaging of inflammation in the brain or spinal cord is substantially more challenging because the skull or spine absorb bioluminescent and near-infrared signals.
In addition to inflammation indicators, fluorescent chemicals have been described, which specifically bind to myelin and may allow for quantification of myelination13. A near-infrared fluorescent probe, 3,3′-diethylthiatricarbocyanine iodide (DBT), was found to specifically bind to myelinated fibers and was validated as a quantitative tool in mouse models of primary myelination defects and in cuprizone-evoked demyelination14. In EAE, the DBT signal was rather increased, reflecting the inflammation of the myelin fibers5.
An additional hallmark of EAE and MS is the BBB breakdown, resulting in increased vascular permeability and the extravasation of blood cells, extracellular fluid, and macromolecules into the CNS parenchyma. This can lead to edema, inflammation, oligodendrocyte damage, and, eventually, demyelination15,16. Hence, visualization of the BBB leak using fluorescent probes, such as fluorochrome-labeled bovine serum albumin5, which normally distribute very slowly from blood to tissue, may be useful to assess EAE.
In the present study, we have assessed the usefulness of different probes in EAE and show the procedure for the most reliable and robust bioluminescent technique. In addition, we discuss the pros and cons of near-infrared probes for MMP activity and BBB integrity.
Protocol
Representative Results
Discussion
본 동영상은 SJL / J 마우스의 EAE의 생체 내 이미징의 생물 발광 및 근적외선 형광을위한 기술을 보여줍니다. 우리는 염증에 민감한 프로브를 사용하여 생물 발광 영상은 주로 시신경염를 표시하고 정량화가 EAE 심각도의 임상 평가 및 약물의 효과에 동의 것으로 나타났다. 신호가 척추에 의해 흡수되기 때문에, 생물 발광 촬상 방법 가능성 EAE 현시 (17)의 기본 위치 인 요추 ?…
Disclosures
The authors have nothing to disclose.
Acknowledgements
이 연구는 독일 연구 협회 (CRC1039 A3) 및 연구 자금 지원 프로그램 헤센, 중개 의학 및 약학 TMP 연구 센터의 주 "Landesoffensive 주르 ENTWICKLUNG wissenschaftlich-ökonomischer Exzellenz"(LOEWE)과 그렇지 크로네-는 Fresenius 재단 지원 (EKFS), 연구 교육 그룹 중개 연구 혁신 – 제약 (TRIP).
Materials
| AngioSpark-680 | Perkin Elmer, Inc., Waltham, USA | NEV10149 | Imaging probe, pegylated nanoparticles, useful for imaging of blood brain barrier integrity |
| MMP-sense 680 | Perkin Elmer, Inc., Waltham, USA | NEV10126 | Imaging probe, activatable by matrix metalloproteinases, useful for imaging of inflammation |
| XenoLight RediJect Inflammation Probe | Perkin Elmer, Inc., Waltham, USA | 760535 | Imaging probe, activatable by oxidases, useful for imaging of inflammation |
| PLP139-151/CFA emulsion | Hooke Labs, St Lawrence, MA | EK-0123 | EAE induction kit |
| Pertussis Toxin | Hooke Labs, St Lawrence, MA | EK-0123 | EAE induction kit |
| IVIS Lumina Spectrum | Perkin Elmer, Inc., Waltham, USA | Bioluminescence and Infrared Imaging System | |
| LivingImage 4.5 software | Perkin Elmer, Inc., Waltham, USA | CLS136334 | IVIS analysis software |
| Isoflurane | Abbott Labs, Illinois, USA | 26675-46-7 | Anaesthetic |
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