Einstein (São Paulo) (Jun 2012)
Evaluation of umbilical cord mesenchymal stem cell labeling with superparamagnetic iron oxide nanoparticles coated with dextran and complexed with Poly-L-lysine
Abstract
Objective: The objective of this study was to evaluate the effect of thelabeling of umbilical cord vein derived mesenchymal stem cells withsuperparamagnetic iron oxide nanoparticles coated with dextran andcomplexed to a non-viral transfector agent transfector poly-L-lysine.Methods: The labeling of mesenchymal stem cells was performedusing the superparamagnetic iron oxide nanoparticles/dextrancomplexed and not complexed to poly-L-lysine. Superparamagneticiron oxide nanoparticles/dextran was incubated with poly-L-lysine inan ultrasonic sonicator at 37°C for 10 minutes for complex formationsuperparamagnetic iron oxide nanoparticles/dextran/poly-L-lysineby electrostatic interaction. Then, the mesenchymal stem cellswere incubated overnight with the complex superparamagnetic ironoxide nanoparticles/dextran/poly-L-lysine and superparamagneticiron oxide nanoparticles/dextran. After the incubation period themesenchymal stem cells were evaluated by internalization of thecomplex superparamagnetic iron oxide nanoparticles/dextran/poly-L-lysine and superparamagnetic iron oxide nanoparticles/dextran byPrussian Blue stain. Cellular viability of labeled mesenchymal stemcells was evaluated by cellular proliferation assay using 5,6-carboxyfluorescein-succinimidyl ester method and apoptosis detectionby Annexin V- Propidium Iodide assay. Results: mesenchymalstem cells labeled with superparamagnetic iron oxide nanoparticles/dextran without poly-L-lysine not internalized efficiently thesuperparamagnetic iron oxide nanoparticles due to its low presencedetected within cells. Mesenchymal stem cells labeled with thecomplex superparamagnetic iron oxide nanoparticles/dextran/poly-L-lysine efficiently internalized the superparamagnetic iron oxidenanoparticles due to greater presence in the cells interior. The viabilityand apoptosis assays demonstrated that the mesenchymal stemcells labeled and not labeled respectively with the superparamagneticiron oxide nanoparticles/dextran/poly-L-lysine continue to proliferateover seven days and the percentage of cells in early or late apoptosisis low compared to the percentage of live cells over the threedays. Conclusion: Our results showed that the use of poly-L-lysinecomplexed with superparamagnetic iron oxide nanoparticles/dextranprovides better internalization of these superparamagnetic iron oxidenanoparticles in mesenchymal stem cells Thus, we demonstratedthat this type of labeling is not cytotoxic to the mesenchymal stemcells, since the viability and apoptosis assays showed that the cellsremain alive and proliferating. The efficiency of this type of labelingin mesenchymal stem cells can provide non-invasive methods formonitoring these cells in vivo
