Abstract:

To explore the cell labeling ability of CM-Dil on bone marrwow mesenchymal stem cells (BMSCs) in vitro as well as its tracking capability in intestine tissues of burned rats.Methods BMSCs were isolated,purified and expanded by the method of adherent culture,and were induced to differentiate into neuron-like cells by basic fibroblast growth factor (bFGF),epidermal growth factor (EGF) and retinoic acid (RA).The surface markers of neuron-like cells differentiated from BMSCs,microtubule-associated protein-2 (MAP-2) and neuron specific nuclear protein (NeuN） were detected by immunocytochemistry.The BMSCs were labeled with CM-Dil at the doses of 4,6,8 mg•L^-1.Then the cytotoxic effect was determined by CCK-8 assay,the labeling rate was examined using flow cytometry.107 BMSCs labeled by CM-Dil were administrated by retro-orbital intravenous injection after burned models of Wistar rats were prepared.The intestine tissues were obtained and fixed on the 2 weeks and 6 months after the burning,then the engraftment of the labeled BMSCs were observed using a laser scanning confocal microscope.Results The nueon-like cells differentiated from BMSCs expressed neuron markers,NeuN and MAP-2. The results of CCK-8 assay showed that compared with control group,the cell viability in 8 mg•L^-1 group was significantly decreased (P<0.05）.There were no significantly differences between 4,6  μg•mL^-1groups and control group.No significant adverse effects on BMSCs were observed during CM-Dil labeling at the dose of 4 mg•L^-1,and the labeling rate was as high as 93.9%.The morphological changes of the BMSCs were not shown.Frozen sections of intestine tissues were performed on the 2 weeks and 6 months after burning,the CM-Dil labeled BMSCs were engrafted at the rat intestine tissues.Conclusion CM-Dil is capable of labeling BMSCs in vitro,thus could be utilized as tracking of BMSCs in the intestine tissue of the burned rats.

Key words: bone marrow mesenchymal stemcells;chloromethylbenzamidodialkylcarbocyanine;burning;tracking