title: Cell seeding density is a critical determinant for copolymer scaffolds-induced bone regeneration.
abstract: Constructs intended for bone tissue engineering (TE) are influenced by the initial cell seeding density. Therefore, the objective of this study was to determine the effect of bone marrow stromal stem cells (BMSCs) density loaded onto copolymer scaffolds on bone regeneration. BMSCs were harvested from rat's bone marrow and cultured in media with or without osteogenic supplements. Cells were seeded onto poly(l-lactide-co-ε-caprolactone) [poly(LLA-co-CL)] scaffolds at two different densities: low density (1 × 10(6) cells/scaffold) or high density (2 × 10(6) cells/scaffold) using spinner modified flasks and examined after 1 and 3 weeks. Initial attachment and spread of BMSC onto the scaffolds was recorded by scanning electron microscopy. Cell proliferation was assessed by DNA quantification and cell differentiation by quantitative real-time reverse transcriptase-polymerized chain reaction analysis (qRT-PCR). Five-millimeter rat calvarial defects (24 defects in 12 rats) were implanted with scaffolds seeded with either low or high density expanded with or without osteogenic supplements. Osteogenic supplements significantly increased cell proliferation (p < 0.001). Scaffolds seeded at high cell density exhibited higher mRNA expressions of Runx2 p = 0.001, Col1 p = 0.001, BMP2 p < 0.001, BSP p < 0.001, and OC p = 0.013. More bone was formed in response to high cell seeding density (p = 0.023) and high seeding density with osteogenic medium (p = 0.038). Poly (LLA-co-CL) scaffolds could be appropriate candidates for bone TE. The optimal number of cells to be loaded onto scaffolds is critical for promoting Extracellular matrix synthesis and bone formation. Cell seeding density and osteogenic supplements may have a synergistic effect on the induction of new bone.
authors.affiliation: Faculty of Medicine and Dentistry, Department of Clinical Dentistry, Center for Clinical Dental Research, University of Bergen, Årstadveien 19, N-5009, Bergen, Norway.
authors.forename: Mohammed A
authors.initials: MA
authors.lastname: Yassin
authors.affiliation: Faculty of Medicine and Dentistry, Department of Clinical Dentistry, Center for Clinical Dental Research, University of Bergen, Årstadveien 19, N-5009, Bergen, Norway.
authors.forename: Knut N
authors.initials: KN
authors.lastname: Leknes
authors.affiliation: Faculty of Medicine and Dentistry, Department of Clinical Dentistry, Center for Clinical Dental Research, University of Bergen, Årstadveien 19, N-5009, Bergen, Norway.
authors.forename: Torbjorn O
authors.initials: TO
authors.lastname: Pedersen
authors.affiliation: Faculty of Medicine and Dentistry, Department of Clinical Dentistry, Center for Clinical Dental Research, University of Bergen, Årstadveien 19, N-5009, Bergen, Norway.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Xing
authors.affiliation: Department of Fibre and Polymer Technology, School of Chemical Science and Engineering, KTH Royal Institute of Technology, Teknikringen 42, SE-100 44, Stockholm, Sweden.
authors.forename: Yang
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Faculty of Medicine and Dentistry, Department of Clinical Dentistry, Center for Clinical Dental Research, University of Bergen, Årstadveien 19, N-5009, Bergen, Norway.
authors.forename: Stein A
authors.initials: SA
authors.lastname: Lie
authors.affiliation: Department of Fibre and Polymer Technology, School of Chemical Science and Engineering, KTH Royal Institute of Technology, Teknikringen 42, SE-100 44, Stockholm, Sweden.
authors.forename: Anna
authors.initials: A
authors.lastname: Finne-Wistrand
authors.affiliation: Faculty of Medicine and Dentistry, Department of Clinical Dentistry, Center for Clinical Dental Research, University of Bergen, Årstadveien 19, N-5009, Bergen, Norway.
authors.forename: Kamal
authors.initials: K
authors.lastname: Mustafa
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects; D001861:Bone Regeneration / Q000187:drug effects*; D002452:Cell Count; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects; D008855:Microscopy, Electron, Scanning; D011108:Polymers / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011917:Rats, Inbred Lew; D060888:Real-Time Polymerase Chain Reaction; D012886:Skull / Q000000981:diagnostic imaging / Q000473:pathology; D054457:Tissue Scaffolds / Q000737:chemistry*; D055114:X-Ray Microtomography
chemical_list: D011108:Polymers; D012333:RNA, Messenger; D004247:DNA
keywords: bone marrow stromal cells; bone regeneration; cell seeding density; osteogenic supplements; polymer scaffolds