Effects of hydroxyapatite/collagen composite on osteogenic differentiation of rat bone marrow derived mesenchymal stem cells

Combination of cells and materials opens a new option for tissue repair and regeneration. The aim of this study is to investigate the effects of hydroxyapatite/collagen composite on the osteogenic differentiation of rat bone marrow derived mesenchymal stem cells. The hydroxyapatite/collagen composites are synthesized by bioinspired mineralization and characterized by Fourier transform infrared spectrometry, X-ray diffraction, scanning electron microscope, thermogravimetric analysis and laser particle size analyzer. Different concentrations of hydroxyapatite/collagen are co-cultured with the rat bone marrow derived mesenchymal stem cells in passages 2-4 on a culture plate. Osteogenic differentiation is evaluated using reverse transcription polymerase chain reaction, alkaline phosphatase spectrophotometry as well as western blotting. The results demonstrate that the developed hydroxyapatite/collagen composite has microstructure and composition that are similar to the natural bone matrix. Hydroxyapatite/collagen treatment can induce osteogenic differentiation of rat bone marrow derived mesenchymal stem cells, as confirmed by the expression of osteoblast-related markers at both messenger RNA and protein levels. The concentration of 75μg/ml may be the optimal inducer. In addition, combining biochemical reagents and hydroxyapatite/collagen has a synergistic interaction on the osteogenic differentiation of rat bone marrow derived mesenchymal stem cells. This provides a new avenue for mechanistic studies of stem cell differentiation and a novel approach to obtain more committed differentiated cells.