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[New porous beta-tricalcium phosphate as scaffold for bone tissue engineering].

OBJECTIVE
To investigate the feasibility of a new kind of porous beta tricalcium phosphate (P-TCP) as a scaffold for the bone tissue engineering.


METHODS
The inverted phase contrast microscope was used to observe the growth of the marrow mesenchymal stem cells (MSCs) in the experimental group and the control group at 10 days. In the experimental group, the MSCs were cultured with beta-TCP(3 mm x 3 mm x 3 mm) in the 24-hole cultivation board, and in the control to control group, only MSCs were cultivated. The scanning electron microscope was used to observe growth of MSCs at 6 days. Cultivated with beta-TCP at 3, 6, 9, 12 days, the MTT assay was used to judge the biocompatibility. The cytotoxicity was analyzed with the method that used the different density (100%, 50%, 10%, 1%, 0%) leaching liquor gained from beta-TCP to raise MSCs. MSCs were induced into the osteoblasts and were mixed with beta-TCP, and the composite was used to repair a large radius bone defect in the rabbit. The specimens were made at 2, 6, 12 weeks. The histology imageology, and the radionuclide bone scan were used to analyze the bone formation.


RESULTS
Some MSCs had a good adherence 4 hours after MSCs were inoculated and had a complete adherence at 12 hours. The cells were shaped like poly-angle, spindle or converge monolayer after 8-10 days. The cells in the two groups had no difference. The cell adhesion was good, when observed by the inverted phase contrast microscope and the scanning electron microscope at 6 days. MTT showed that the absorbance (A) was not statistically different between the experimental group and the control group (P > 0.05); the different density leaching liquor had no cytotoxicity at the different time points. Histology, X-ray, and CT tomograph showed that it could repair the large radius bone defect in the rabbit and its in vivo degradation rate was the same as the bone formation rate.


CONCLUSION
The new porous beta-TCP has a unique three dimensional (3D) stereochemical structure and superordinary physico-chemical property, and so it is a good scaffold for the bone tissue engineering.