Efficient in vitro labeling rabbit neural stem cell with paramagnetic Gd-DTPA and fluorescent substance

Objectives: The aim of this study is to label rabbit neural stem cells (NSCs) by using standard contrast agents (Gd-DTPA) in combination with PKH26 and in vitro track them with MR imaging.

Materials and methods: NSCs from prenatal brains of rabbits were cultured and propagated. Intracellular uptake of Gd-DTPA was achieved by using a non-liposomal lipid transfection reagent (Effectene) as the transfection agent. After labeling with Gd-DTPA, cells were incubated with cellular membrane fluorescent dye PKH26. The labeling effectiveness and the longevity of Gd-DTPA maintenance were measured on a 1.5T MR scanner. The influence of labeling on the cellular biological behaviors was assessed by cellular viability, proliferation and differentiation assessment.

Results: The labeling efficiency of Gd-DTPA was up to 90%. The signal intensity on T1-weighted imaging and T1 values of labeled cells were significantly higher than those of unlabeled cells (P<0.05). The minimal number of detectable cells for T1-weighted imaging was 5×10(3). Cellular uptake of Gd-DTPA was maintained until 15 days after initially labeling. There was no significant difference in the cellular viability and proliferation between the labeled and unlabeled NSCs (P>0.05). Normal glial and neuronal differentiation remained in labeled NSCs like unlabeled NSCs.

Conclusion: Highly efficient labeling NSCs with Gd-DTPA could be achieved by using Effectene. This method of labeling NSCs allows for tracking cells with MR imaging, and without alterations of cellular biological behaviors.