Introduction

Demineralized allografts and mesenchymal stromal cells have been used to promote bone regeneration. However, degree of demineralization of cortical bone for combination therapy with adipose derived mesenchymal stromal cells (ad-MSCs) has not been clarified.

Objectives

In vitro osteogenic ability of ad-MSCs on allografts was investigated in relation to the degree of demineralization.

Methods

It was divided into 3 groups according to the degrees of demineralization by 0.6 N hydrochloric acid; partially demineralized bone for 12 h, PDB; fully demineralized bone for 48 h, FDB; non-demineralized bone, NDB as control. Grafts were prepared as a disc type in the diameter of 6 mm for in vitro evaluation. The degree of demineralization and structure of allografts were evaluated by micro-computed tomography (CT) and scanning electron microscope (SEM). The adhesion and proliferation rates of ad-MSCs were measured by MTS assay.

Results

Osteogenic related genes were assessed by real-time PCR. Demineralization rates of PDB and FOB were 57.13% and 92.30%, respectively. Adhesion rates of ad-MSCs on the NOB, PDB and FOB, respectively, were 53.41%, 60.65% and 61.32%. Proliferation rate of ad-MSCs on FOB from 2 days after culture increased significantly than other groups (p<0.05). Osteogenic genes of ALP, BMP-7 and TGF-β FDB group at the day 3 of culture also elevated significantly as compared to other groups.

Conclusions

It was suggested that fully demineralized bone might be a suitable scaffold for biocompatibility and osteogenic differentiation of ad-MSCs in the repair of bone defects.