abstract
The core aim of this study was to investigate zinc (Zn)and zinc and strontium (ZnSr)-containing brushite-forming beta-tricalcium phosphate (TCP) cements for their effects on proliferation and differentiation of osteoblastic-like cells (MC3T3-E1 cell line) as well as for their in vivo behaviour in trabecular bone cylindrical defects in a pilot study. In vitro proliferation and maturation responses of MC3T3-El osteoblastic-like cells to bone cements were studied at the cellular and molecular levels. The Zn- and Sr-containing brushite cements were found to stimulate pre-osteoblastic proliferation and osteoblastic maturation. Indeed, MC3T3-E1 cells exposed to the powdered cements had increased proliferative rates and higher adhesiveness capacity, in comparison to control cells. Furthermore, they exhibited higher alkaline phosphatase (ALP) activity and increased Type-I collagen secretion and fibre deposition into the extracellular matrix. Proliferative and collagen deposition properties were more evident for cells grown in cements doped with Sr. The in vivo osteoconductivc properties of the ZnCPC and ZnSrCPC cements were also pursued. Histological and histomorphometric analyses were performed at 1 and 2 months after implantation, using carbonated apatite cement (Norian SRS (R)) as control. There was no evidence of cement-induced adverse foreign body reactions, and furthermore ZnCPC and ZnSrCPC cements revealed better in vivo performance in comparison to the control apatite cement. Additionally, the presence of both zinc and strontium resulted in the highest I:ate of new bone formation, These novel results indicate that the investigated ZnCPC and ZnSrCPC cements are both biocompatible and osteoconductive, being good candidate materials to use as bone substitutes.
keywords
CALCIUM-PHOSPHATE; IN-VIVO; ZINC RELEASE; STRONTIUM; DIFFERENTIATION; INJECTABILITY; CYTOCOMPATIBILITY; HYDROXYAPATITE; PROLIFERATION; BIOMATERIAL
subject category
Cell Biology; Engineering; Materials Science
authors
Pina, S; Vieira, SI; Rego, P; Torres, PMC; Silva, OABDE; Silva, EFDE; Ferreira, JMF
our authors
José Maria da Fonte Ferreira
Retired Professor
Paula Maria da Costa Torres
Assistant Researcher
Sandra Cristina de Almeida Pina
Post-doc Fellowshipacknowledgements
To CICECO and to CBC for the support and to the Portuguese Foundation for Science and Technology for the project REEQ/1023/BIO/2005 and for the fellowship grants of S.P. (SFRH/BPD/64119/2009), S.I.V. (SERH/BPD/19515/2004) and P.M.CT. (SFRH/BD/62021/2009). The authors are also very grateful to Prof. Doutor Henrique Bicha Castel, Director of the Service of Medicine and Experimental Surgery, Hospital of Santa Maria, Lisbon, for the facilities supply in experimental animal studies, according to European regulations and following permission granted by the Ethical Committee. In addition, the authors are thankful to A. Pinto, Institute of Molecular Medicine, Lisbon, for the preparation of the sections for histological and histomorphometric analysis.