文献：

High and Low Molecular Weight Fluorescein Isothiocyanate (FITC)–Dextrans to Assess Blood-Brain Barrier Disruption: Technical Considerations.

文献链接：

https://www.docin.com/p-1398611854.html

作者：

Angelika Hoffmann·Jörg Bredno。Michael Wendland·Nikita Derugin·Peter OharaMax Wintermark

相关产品：

荧光素-葡聚糖 FITC-Dextran

原文摘要：

This note is to report how histological preparation techniques infuence the extravasation pattern of thedifferent molecular sizes of fluoresccin isothiocyanate(FITC)dextrans, typically used as markers for blood-brain barier leakage.By using appropriate preparationmethods, false negative results can be minimized. Wistarrats underwent a 2-h middle cerebral artery occlusion andmagnetic resonance imaging.After the last imaging scan,Evans blue and FITC-dextrans of4,40，and 70 kDamolecular weight were injected. Different histologicalpreparation methods were used, Sites of blood-brain barrierleakage were analyzed by fluorescence microscopy.Extravasation of Evans blue and high molecular FITC dextrans(40and70kDa)in the infarcted region could bedetected with all preparation methods used. If exposeddirectly to saline, the signal intensity of these FITCdextrans decreased,Extravasation of the 4-kDa lowmolecular weight FITC-dextran could only be detectedusing freshly fozen tissue sections. Preparations involvingparaformaldehyde and suerose resulted in the 4-kDa FITCdextran dissolving in these reactants and being washed out,giving the false negative result of no extravasation. FITCdextrans represent a valuable tool to characterize alteredblood-brain barrier permeability in animal models. Diffu-sion and washout of low molecular weight FITC-dextrancan be avoided by direct immobilization through immediatefreezing of the tissue. This pitfall needs to be known toavoid the false impression that there was no extravasationof low molecular weight FITC-dextrans.

组织学制备技术如何影响异硫氰酸荧光素（FITC）葡聚糖的不同分子大小的外渗模式，这些葡聚糖通常用作标志物。通过使用适当的制备方法，可以减少假阴性结果。2小时的大脑中动脉闭塞和磁共振成像。在成像扫描后，注射分子量为4、40和70 kD的FITC葡聚糖。采用不同的组织修复方法，用荧光显微镜分渗漏部位。所有制备方法均能检测到高分子FITC葡聚糖（40和70kDa）的外渗。如果直接暴露于盐水，这些FITC外泌物的信号强度降低。含有多聚甲醛和蔗糖的制剂导致4-kDa FITCdextra溶解在这些反应物中并被冲洗掉，给出没有外渗的假阴性结果。

图为：FITC-dextrans结构式

FITC-dextrans是表征动物模型中血脑屏障通透性变化的一种有价值的工具。低分子量FITC葡聚糖的分化和冲刷可以通过直接固定组织来避免。需要知道这个陷阱，以消除低分子量FITC葡聚糖没有外渗的错误印象。