FITC-Dextran (MW 10000)

FITC-Dextran is a fluorescent probe for fluorescein isothiocyanate (FITC) dextran (Ex=495 nm; Em=525 nm). In cell permeability studies, FITC-Dextran can assess BBB permeability and BBB disruption ^[1,2].

When analyse the lysosomal pH in cultured cells using the fluorescent probe fluorescein isothiocyanate (FITC)-dextran together with a dual-emission ratiometric technique suitable for flow cytometry. Fluorescence-labeled dextran is endocytosed and accumulated in the lysosomal compartment. FITC shows a pH-dependent variation in fluorescence when analyzed at maximum emission wavelength and no variation when analyzing at the isosbestic point, thereby the ratio can be used to determine the lysosomal pH^[2].Fitc-glucan increased intestinal epithelial paracellular permeability after 21 days of incubation^[5]. When examined their expression and FITC-Dextran uptake by various human DC preparations. In contrast to immature Mo-DC, the FITC-dextran uptake by LC was not inhibited effectively by mannose, an inhibitor for MMR-mediated FITC-dextran uptake^[7].

After 6 h of fasting in our C3H/HeOu mice, plasma concentrations of 4-kDa FITC-Dextran peaked at 45 min after oral administration[3]. The fluorescence of small vessels and neovascular tufts could be observed clearly following RO injection of 0.05 ml of 25 mg/ml or 50 mg/ml FITC-dextran. No visible damage to tissues adjacent to the injection site was discovered. Vitreous blood flow was gradually reduced from P0 to P5 and eventually disappeared in P17 OIR mice, as demonstrated by FITC-dextran perfusion. The retinal NV areas assessed by isolectin B4 were larger than those assessed by FITC-dextran, but the retinal avascular areas were smaller[4]. When measured fluorescence recovery after photobleaching (FRAP) of fluorescein isothiocyanate (FITC)-labelled 10 and 250 kDa dextran (FITC-Dextran) in isolated rat descending colonic crypts.FRAP of either 10 or 250 kDa FITC-Dextran in crypt lumens was almost complete within 2-3 min. In the presence of amiloride (0.1 mM), or in the absence of Na+, the rate of FITC-Dextran uptake into the crypt lumens was reduced by 70-80 %^[6].

References:
[1]: Natarajan R, Northrop N, et,al. Fluorescein Isothiocyanate (FITC)-Dextran Extravasation as a Measure of Blood-Brain Barrier Permeability. Curr Protoc Neurosci. 2017 Apr 10;79:9.58.1-9.58.15. doi: 10.1002/cpns.25. PMID: 28398646; PMCID: PMC5470084.
[2]: Eriksson I, Öllinger K, et,al.Analysis of Lysosomal pH by Flow Cytometry Using FITC-Dextran Loaded Cells. Methods Mol Biol. 2017;1594:179-189. doi: 10.1007/978-1-4939-6934-0_11. PMID: 28456983.
[3]: Woting A, Blaut M. Small Intestinal Permeability and Gut-Transit Time Determined with Low and High Molecular Weight Fluorescein Isothiocyanate-Dextrans in C3H Mice. Nutrients. 2018 May 28;10(6):685. doi: 10.3390/nu10060685. PMID: 29843428; PMCID: PMC6024777.
[4]: Li J, Wu Y, et,al. Retro-orbital injection of FITC-dextran combined with isolectin B4 in assessing the retinal neovascularization defect. BMC Ophthalmol. 2021 May 11;21(1):208. doi: 10.1186/s12886-021-01969-5. PMID: 33975571; PMCID: PMC8112026.
[5]: Sun X, Yang Q, et,al.AMPK improves gut epithelial differentiation and barrier function via regulating Cdx2 expression. Cell Death Differ. 2017 May;24(5):819-831. doi: 10.1038/cdd.2017.14. Epub 2017 Feb 24. PMID: 28234358; PMCID: PMC5423107.
[6]: Thiagarajah JR, Pedley KC, et,al. Evidence of amiloride-sensitive fluid absorption in rat descending colonic crypts from fluorescence recovery of FITC-labelled dextran after photobleaching. J Physiol. 2001 Oct 15;536(Pt 2):541-53. doi: 10.1111/j.1469-7793.2001.0541c.xd. PMID: 11600688; PMCID: PMC2278881.
[7]: Kato M, Neil TK,et,al. Expression of multilectin receptors and comparative FITC-dextran uptake by human dendritic cells. Int Immunol. 2000 Nov;12(11):1511-9. doi: 10.1093/intimm/12.11.1511. PMID: 11058570.