Intrafibrillar-silicified collagen scaffolds enhance the osteogenic capacity of human dental pulp stem cells.
OBJECTIVE
The present study investigated the effects of intrafibrillar-silicified collagen scaffolds (ISCS) on the osteogenic differentiation of human dental pulp stem cells (hDPSCs) in vitro and in vivo.


METHODS
The hDPSCs were co-cultured with ISCS or nonsilicified collagen scaffolds (NCS) in control medium (CM) or osteogenic differentiation medium (ODM). Cell cycle and cell apoptosis were analyzed with flow cytometry to measure the viability of hDPSCs. Reverse transcription-polymerase chain reaction (RT-PCR) and western blotting were used to evaluate the expression levels of osteogenic marker genes and proteins of hDPSCs. Alkaline phosphatase (ALP) staining and alizarin red S assay were used to evaluate the ALP activity of hDPSCs and their calcium deposition potential. In addition, hDPSCs and scaffolds were implanted subcutaneously in nude mice for 8 weeks. Harvested tissues were immunohistochemically stained for osteocalcin (OCN) expression from hDPSCs, and stained with alizarin red S for examination of their calcium deposition in vivo.


RESULTS
The ISCS had no adverse effect on hDPSCs, promoted their proliferation, and significantly up-regulated the expression of osteogenesis-related genes and proteins. The hDPSCs co-cultured with ISCS in ODM exhibited the highest ALP activity and calcium deposition in vitro. The ISCS promoted the OCN expression and calcium deposition of hDPSCs after ectopic transplantation in vivo.


CONCLUSIONS
Intrafibrillar-silicified collagen scaffolds significantly promoted the proliferation, osteogenic differentiation and mineralization of hDPSCs, when compared with NCS. This study demonstrates combining the use of hDPSCs and ISCS to promote bone-like tissue formation is a promising approach for clinical bone repair and regeneration.
State Key Laboratory of Military Stomatology, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Changle Xi Road 145, Xi'an 710032, China.
Li-na
LN
Niu
State Key Laboratory of Military Stomatology, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Changle Xi Road 145, Xi'an 710032, China.
Jia-qi
JQ
Sun
Department of Stomatology, Affiliated Hospital of Academy of Military Medical Science, Beijing, 100000, China.
Qi-hong
QH
Li
State Key Laboratory of Military Stomatology, Department of Oral Anatomy and Physiology, School of Stomatology, Fourth Military Medical University, Changle Xi Road 145, Xi'an 710032, China.
Kai
K
Jiao
State Key Laboratory of Military Stomatology, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Changle Xi Road 145, Xi'an 710032, China.
Li-juan
LJ
Shen
State Key Laboratory of Military Stomatology, Medical Department, School of Stomatology, Fourth Military Medical University, Changle Xi Road 145, Xi'an 710032, China.
Dan
D
Wu
Department of Endodontics, College of Dental Medicine, Georgia Regents University, Augusta, GA, USA. Electronic address: tayfranklin7@gmail.com.
Franklin
F
Tay
State Key Laboratory of Military Stomatology, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Changle Xi Road 145, Xi'an 710032, China. Electronic address: jhchen@fmmu.edu.cn.
Ji-hua
JH
Chen
D000293:Adolescent; D000328:Adult; D000469:Alkaline Phosphatase / Q000032:analysis; D000818:Animals; D017209:Apoptosis / Q000502:physiology; D002113:Calcification, Physiologic / Q000502:physiology; D018929:Cell Culture Techniques; D002453:Cell Cycle / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology; D002470:Cell Survival / Q000502:physiology; D002478:Cells, Cultured; D003094:Collagen / Q000737:chemistry*; D003470:Culture Media; D003782:Dental Pulp / Q000166:cytology*; D006801:Humans; D066298:In Vitro Techniques; D051379:Mice; D008819:Mice, Nude; D015675:Osteocalcin / Q000032:analysis; D010012:Osteogenesis / Q000502:physiology*; D012824:Silicic Acid / Q000737:chemistry*; D033581:Stem Cell Transplantation / Q000379:methods; D013234:Stem Cells / Q000502:physiology*; D040521:Subcutaneous Tissue / Q000033:anatomy & histology; D023822:Tissue Engineering / Q000379:methods; D054457:Tissue Scaffolds / Q000737:chemistry*; D055815:Young Adult
D003470:Culture Media; D015675:Osteocalcin; D012824:Silicic Acid; D003094:Collagen; D000469:Alkaline Phosphatase
Collagen scaffold; Human dental pulp stem cells; Intrafibrillar silicification; Osteogenic differentiation