Superparamagnetic iron oxide labeling of spinal cord neural stem cells genetically modified by nerve growth factor-beta.

This study established superparamagnetic iron oxide (SPIO)-labeled nerve growth factor-beta (NGF-beta) gene-modified spinal cord-derived neural stem cells (NSCs). The E14 rat embryonic spinal cord-derived NSCs were isolated and cultured. The cells of the third passage were transfected with plasmid pcDNA3-hNGFbeta by using FuGENE HD transfection reagent. The expression of NGF-beta was measured by immunocytochemistry and Western blotting. The positive clones were selected, allowed to proliferate and then labeled with SPIO, which was mediated by FuGENE HD transfection reagent. Prussian blue staining and transmission electron microscopy (TEM) were used to identify the SPIO particles in the cells. The distinctive markers for stem cells (nestin), neuron (beta-III-tubulin), oligodendrocyte (CNPase) and astrocyte (GFAP) were employed to evaluate the differentiation ability of the labeled cells. The immunocytochemistry and western blotting showed that NGF-beta was expressed in spinal cord-derived NSCs. Prussian blue staining indicated that numerous blue-stained particles appeared in the cytoplasma of the labeled cells. TEM showed that SPIO particles were found in vacuolar structures of different sizes and the cytoplasma. The immunocytochemistry demonstrated that the labeled cells were nestin-positive. After differentiation, the cells expressed beta-III-tubulin, CNPase and GFAP. It was concluded that the SPIO-labeled NGF-beta gene-modified spinal cord-derived NSC were successfully established, which are multipotent and capable of self-renewal.