Adipose-derived stem cells loaded chitosan scaffold to promote the healing of calvarial defect：an experimental study

Abstract:

Objective：To investigate the effect of tissue engineering biomaterials based on adipose-derived stem cells（ADSCs） for healing calvarial defects. Methods：ADSCs were isolated，cultured and conducted the three-lineage differentiation of osteogenesis，adipogenesis and chondrogesis. Porous chitosan-based scaffolds were prepared and ADSCs were seeded onto the surface of scaffold. Microstructural changes before and after the implantation of ADSCs were detected by scanning electron microscope（SEM）. Cell viability after ADSCs loaded on scaffolds was determined by cell viability assays. A total of 15 male Sprague Dawley（SD） rats were selected to create cranial defect models，and the defects were left in empty or implanted with chitosan scaffolds which were seeded with low（2.5×105） or high densities（1×106） of ADSCs. After operation of 8 weeks，samples were collected for Micro-CT analysis. And then，those samples were decalcified，paraffin embedded and sectioned；hematoxylin-feosin staining and immunohistochemistry stain－ing were performed to observe the bone formation biomarker of bone sialoprotein. Results：ADSCs were able to induce osteoge－nesis，chondrogenesis and adipogenesis. Data from SEM and cell viability assays showed that chitosan-based scaffold had porous structure，and ADSCs were able to attach to the surface of scaf－folds and proliferate，and proliferation effects on scaffolds sur－face were not significantly different when compared with those on the culture plate. In the rat calvarial defect model，the bone volume ratio（BV/TV） in the high-density ADSCs/chitosan scaf－fold group was increased by 140.8%（P=0.014） and 37.4%（P=0.036） when compared with that in the blank control group and the low-density ADSCs/chitosan group，respectively. Compared with that in the control group，bone density in the low-density ADSCs/chitosan group and high-density ADSCs/chitosan group were in－creased by 29.4%（P=0.123） and 64.1%（P=0.022），respectively. Histological results showed that distribution and quantity of the new bone tissue in the bone defect area were consistent with results of Micro-CT analysis. Expression of bone formation markers of bone sialoprotein had an increasing tendency in the high-density group. Conclusion：High density of ADSCs-loaded chitosan scaffolds can effectively promote the healing of calvarial defect in rats.