Effect of calcium phosphate bone cement scaffolds loaded with emodin on osteogenic activity of osteoblasts / 中华创伤杂志

ABSTRACT

Objective:To explore the effect of calcium phosphate cement（CPC）scaffold loaded with emodin（EMO）on osteogenic activity of osteoblasts.Methods:The bone cement scaffold was prepared by mixing EMO powder and CPC powder（ratio 1∶9），adding citric acid and then was poured into polytetrafluoroethylene mold（EMO-CPC group）. A dose of 0.36 g CPC powder was mixed with citric acid and injected into the polytetrafluoroethylene mold（CPC group）. General morphology，setting time（initial setting time and final setting time），injection rate and compressive strength of stents were compared between the two groups. Primary osteoblasts were extracted and co-cultured with two sets of scaffolds. After co-culture for 3 days，their characterization was observed by scanning electron microscopy. Live/dead cell staining and 3-（4,5-dimethylthiazole-2）-2,5-diphenyltetrazolium bromide（MTT）colorimetric method were used to detect cell viability，toxicity and proliferation activity of scaffolds. Two sets of scaffolds were stained with immunofluorescence for osteopontin（OPN），and protein expression was observed under an inverted fluorescence microscope. After co-culture for 7 days，tetrazolium nitro blue/5-bromo-4-chloro- 3-indolyl-phosphate（NBT/BCIP）staining method was used for alkaline phosphatase（ALP）staining. After co-culture for 14 days，two sets of scaffolds were stained with Alizarin Red to detect their osteogenic activity.Results:Two sets of stents showed relatively smooth and flat topography under the scanning electron microscope. There were no significant differences in initial setting time，final setting time，injection rate and compressive strength of stents between two groups（ P > 0.05）. After co-culture for 3 days，the osteoblast clusters were adhered to the surface of the EMO-CPC scaffold，with good shape. Viable cell rate reached（98.2 ± 0.1）% in EMO-CPC group and（90.2% ± 0.1）% in CPC group（ P <0.05）. Cell proliferation activity in EMO-CPC group was stronger than that in CPC group（ P < 0.05）. OPN-specific staining showed that EMO-CPC group had stronger OPN protein fluorescence expression compared to CPC group. After co-culture for 7 days，expression of ALP in EMO-CPC group was higher than that in CPC group. After co-culture for 14 days，staining intensity of Alizarin Red in EMO-CPC group was more significant than that in CPC group. Conclusions:The EMO-CPC scaffold can provide a suitable environment for the growth of osteoblasts for it has better biocompatibility，cell proliferation and osteogenic activity than the CPC scaffold.