FITC-Dextran (MW 150000) is a fluorescein isothiocyanate (FITC) dextran fluorescent probe with excitation at 491 nm and emission at 518 nm. It is used as a marker to reveal cell damage caused by heat shock and to study both the early and late stages of apoptosis. Additionally, FITC-Dextran (MW 150000) is employed in perfusion studies and fluorescent microlymphography in animals to investigate processes affecting blood-brain barrier (BBB) permeability. This compound also serves as a fluorescent probe for studying cell permeability.

Cell Labeling: Suitable for labeling apoptotic HeLa cells and human peripheral blood mononuclear cells (PBMC), as live HeLa and PBMC are not stained by FITC-Dextran. First, cells undergo apoptosis induction by incubating at 43.5°C for 1 hour and then at 37°C for 8 hours. Next, suspend the cells in 100 μL of culture medium, mix in a Q-prep tube with 10 μL of propidium iodide (PI) and 10 μL of FITC-Dextran (MW 150000), achieving final concentrations of 7.5 μM for PI and 1.13 μM for FITC-Dextran. Incubate cells in the dark at room temperature for 25 minutes. Centrifuge the labeled cells with 3 mL culture medium at 500 g for 10 minutes. Following centrifugation, resuspend cells in 1 mL of culture medium and analyze using flow cytometry or fluorescence microscopy (PI: Ex=500 nm, Em=600 nm; FITC-Dextran (MW 150000): Ex=495 nm, Em=525 nm). Paracellular Permeability Testing [4]: Add FITC-Dextran (0.1 mg/mL) to the basal culture medium in the transwell chamber. After 15 minutes, collect medium from the transwell insert and measure fluorescence signal (Ex=485 nm, Em=538 nm). Determine the FITC-Dextran concentration based on fluorescence intensity and calculate permeability.

The above information is based on published literature. Experimental procedures should be appropriately modified to meet specific research demands.

Assessment of intestinal barrier function involves the following steps: 1. Subject mice to a 4-hour fasting period. 2. Administer FITC-Dextran (MW 150000) orally at a dosage of 0.6 mg/g to the mice. 3. Measure the fluorescence intensity within four hours (Ex nm/Em 520 nm).