title: [In vitro quantum dot-labeled rat bone marrow mesenchymal stem cells].
abstract: OBJECTIVE To explore the cytotoxicity, labeled time, marking rate, and effect on adhesion of quantum dot 655 (QD655) labeled rat bone marrow mesenchymal stem cells (BMSCs) in vitro, and to confirm its feasibility for stem cell labeling and tracer means for rat.
  
  
  METHODS
  BMSCs were collected from the femur and tibia bone marrow cavity of a 2-week-old SD rat, cultured and identified. The 3rd passage of BMSCs were incubated with QD655 as the experimental group according to the recommended concentration of the markers. The cells were not labeled by QD655 as control group. The cell survival rate after QD655 labeling was detected by trypan-blue exclusion. The effect of QD655 on cell proliferation was observed by MTT. The osteogenic differentiation potential was identified by Alizarin red staining, alkaline phosphatase (ALP) staining, and real-time fluorogenic quantitative PCR. At immediately, 1, 2, 4, and 6 weeks, fluorescent microscopy was used to observe the labeled rate and scanning electron microscope was used to observe the cell adhesion to scaffold (bioglass/collagen composite).
  
  
  RESULTS
  The cell survival rates were more than 90% in both experimental group and control group, showing no significant difference (P > 0.05). There was no significant difference in the cell proliferation between 2 groups (P > 0.05). Alizarin red staining and ALP staining showed positive results. Real-time fluorogenic quantitative PCR result showed that the mRNA expression levels of osteopontin, osteocalcin, collagen type I, ALP, and BMP-2 in the experimental group was significantly higher than those in the control group. The labeled rates were 96.50% +/- 1.59%, 93.30% +/- 1.51%, 72.40% +/- 2.90%, 40.10% + 3.60%, and 10.00% +/- 1.70% immediately, 1, 2, 4, and 6 weeks after labeling, respectively. The labeled rate in the control group was 0. Scanning electron microscope showed a good distribution of fusiform or polygonal cells in the pores of scaffold.
  
  
  CONCLUSIONS
  QD655 can be used as a labeling marker for BMSCs. Rat BMSCs labeled with QD655 is of high efficiency and safety.
authors.affiliation: Department of Orthopaedics and Traumatology, Nanfang Hospital, Southern Medical University, Guangzhou Guangdong, 510515, P.R. China
authors.forename: Xiaorui
authors.initials: X
authors.lastname: Jiang
authors.forename: Xinxin
authors.initials: X
authors.lastname: Zhang
authors.forename: Keyue
authors.initials: K
authors.lastname: Yang
authors.forename: Shan
authors.initials: S
authors.lastname: Jiang
authors.forename: Dan
authors.initials: D
authors.lastname: Jin
authors.forename: Dan
authors.initials: D
authors.lastname: Wang
authors.forename: Guoxian
authors.initials: G
authors.lastname: Pei
mesh_terms: D000818:Animals; D015415:Biomarkers; D001854:Bone Marrow Cells / Q000166:cytology*; D002478:Cells, Cultured; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D045663:Quantum Dots; D051381:Rats; D017207:Rats, Sprague-Dawley; D023822:Tissue Engineering / Q000379:methods
chemical_list: D015415:Biomarkers