Characterization of the stemness and osteogenic potential of oral and sinus mucosal cells

Abstract

Background/purpose: Covering the wounds from guided bone regeneration and sinus floor elevation with oral and sinus mucosa is a fundamental criterion for success. This study aimed to verify the regeneration capability of the mucosal connective tissue stromal cells by characterizing their stemness and osteogenic potentials.

Methods: Bone marrow stromal cells (BMSCs), alveolar mucosa cells (AMCs), keratinized gingival cells (KGCs), and sinus mucosal cells (SMCs), were isolated from four Sprague-Dawley rats. The morphology and viability of the cells were investigated under a confocal microscope and by Alamar Blue. Stem cell surface markers were evaluated by flow cytometry. Expressions of pluripotent factors after initial seeding and an early osteogenic gene following 24 h of osteoinduction were evaluated by realtime PCR. Trilineage differentiation capability in long-term inductive cell culture was assessed by Alizarin Red, Alcian Blue, and Oil Red O staining.

Results: BMSCs and AMCs were larger cells with smaller aspect ratios relative to KGCs and SMCs, and BMSCs revealed the greatest initial viability but the slowest proliferation. More than 94% of BMSCs, AMCs, and KGCs were double-positive for CD73 and CD90. Compared with BMSCs, AMCs expressed significantly higher Oct4 but reduced Cbfa1 after initial seeding, and AMCs and SMCs expressed significantly higher Cbfa1 following 24 h of osteoinduction. In long-term inductive cell culture, osteogenesis was observed in BMSCs, AMCs, and SMCs, chondrogenesis was observed in BMSCs, AMCs, and KGCs, and adipogenesis was evident in only BMSCs.

Conclusion: AMCs contain a high percentage of stem/progenitor cells and show differentiation capability toward osteogenic lineage.

Keywords: Bone regeneration; Gingiva; Mesenchymal stem cells; Nasal mucosa.