Abstract:

Objective

To investigate the methods of isolation， cultivation and characterization as well as the ability of mult-directional differentiation of mesenchymal stem cells（MSCs） derived from human condyle with hyperplasia， so as to pave the way for searching the new source of seed cells in bone tissue engineering.

Methods

Bone marrow were collected by irrigation from resected human condyle， mononuclear cells were isolated by density gradient centrifugation and cultured in vitro.The high purity of MSCs were obtained by keeping the adherent cells and removal of nonadherent cells repeatedly.P3 or P4 MSC populations were collected and examined as follow：（1）Drawing a growth curve of the MSCs by the methods of MTT.（2）Detecting expressed the surface marks and the growing circle of MSCs by flow cytometric analysis.（3）The efficiencies of mult-directional differentiation into adipocytes， osteoblast and neuron-like cell were assessed by related methods.

Results

（1）The highly uniformed MSCs were obtained by density gradient centrifugation and keeping the adherent cells derived from human condyle bone marrow and the MSCs showed long fusiform and fibroblast-like shaped after repeated passages.（2）The growth curve by MTT displayed that every passage experienced dissociation period， adherence period， incubation period， log phase and platform period.（3）The cell surface marks assay with flow cytometry indicated that these MSCs expressed CD44， CD29 and CD55 in high percentage （about 100%， 99.8% and 86.6% respectively）， and expressed CD34， CD45 and CD106 in low percentage （about 0.5%， 2.9% and 6.3% respectively）.（4）The cell circle assay displayed G₀+G₁ stage was in high percentage （about 91.9%）， but G₂ and S stage were in low percentage （about 2.4% and 5.7% respectively）.（5）Under inductive medium in vitro， the MSCs could be induced into adipocyte which were positive when stained by Sudan black B and oil red O； into osteoblasts which were positive when stained by Von kossa and alizarin red； as well as into neuron-like cell which were positive when stained by Toluidine Blue and GFAP immunohistochemistry.

Conclusions

The highly uniformed MSCs derived from human condyle can be obtained.These MSCs possess the ability of mult-directional differentiation， and can be used as a new source of seed cells in bone tissue engineering.

Key words: Mandibular condyle, Bone marrow, Mesenchymal stem cells （MSCs）, Differentiation