title: Osteogenic differentiation and ectopic bone formation of canine bone marrow-derived mesenchymal stem cells in injectable thermo-responsive polymer hydrogel.
abstract: This study describes an injectable, thermo-responsive hyaluronic acid-g-chitosan-g-poly(N-isopropylacrylamide) (HA-CPN) copolymer for bone tissue engineering. The wettability, temperature-dependent change of water content, and volume of HA-CPN hydrogel were measured, together with its biocompatibility in vitro and in vivo. The dried hydrogel morphology shows a three-dimensional, porous structure with interconnected pores. Canine bone marrow-derived mesenchymal stem cells (cBMSCs) were encapsulated in HA-CPN hydrogel and osteoinduction was assessed by comparing samples with different osteogenic differentiation induction times but with the same total cell culture time. Cell proliferation and time-dependent osteogenic differentiation, evident from secretion of extracellular matrix and formation of mineral deposits, were observed. The cells showed better proliferation in HA-CPN hydrogel than on tissue culture polystyrene after osteo-induced for 21 days and higher alkaline phosphatase activity regardless of osteo-induction times. Mineralization extent of cBMSCs in HA-CPN followed by Alizarin red stains showed positive stained nodules after osteo-induced longer than 7 days. The cells/hydrogel construct also showed increased mechanical strength and elasticity after osteogenic differentiation, and the increase could be correlated with osteo-induction time. In vivo studies confirmed the biocompatibility and bioresorption of the HA-CPN hydrogel and ectopic bone formation when the hydrogel was used as a cell carrier for osteo-induced cBMSCs and implanted in nude mice subcutaneously. Taken together, the results indicate the feasibility and efficacy of HA-CPN hydrogel as an injectable bone tissue engineering scaffold with cBMSCs.
authors.affiliation: Department of Chemical and Materials Engineering, Chang Gung University, Kwei-San, Taoyuan, Taiwan, Republic of China.
authors.forename: Han-Tsung
authors.initials: HT
authors.lastname: Liao
authors.forename: Chien-Tzung
authors.initials: CT
authors.lastname: Chen
authors.forename: Jyh-Ping
authors.initials: JP
authors.lastname: Chen
mesh_terms: D000178:Acrylamides / Q000494:pharmacology; D000180:Acrylic Resins; D017667:Adipocytes / Q000187:drug effects / Q000378:metabolism; D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D001854:Bone Marrow Cells / Q000187:drug effects / Q000201:enzymology / Q000473:pathology*; D002452:Cell Count; D002454:Cell Differentiation / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D048271:Chitosan / Q000494:pharmacology; D019902:Chondrocytes / Q000187:drug effects / Q000378:metabolism; D002828:Choristoma / Q000473:pathology*; D004285:Dogs; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000494:pharmacology*; D007267:Injections; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000201:enzymology / Q000473:pathology* / Q000648:ultrastructure; D051379:Mice; D008819:Mice, Nude; D008856:Microscopy, Fluorescence; D010006:Osteoblasts / Q000187:drug effects / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects*; D044367:Phase Transition / Q000187:drug effects; D011108:Polymers / Q000494:pharmacology; D013194:Staining and Labeling; D013696:Temperature
chemical_list: D000178:Acrylamides; D000180:Acrylic Resins; D011108:Polymers; C052970:poly-N-isopropylacrylamide; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D048271:Chitosan; D000469:Alkaline Phosphatase