ABSTRACT
BACKGROUND:Our previous studies have shown that strontium-doped calcium polyphosphate containing low-dose strontium appears to have a significant effect on angiogenesis-related behaviors of monocultured umbilical vein endothelial cells and osteoblasts. OBJECTIVE:To investigate the effect of strontium-doped calcium polyphosphate on angiogenesis-related behaviors of umbilical vein endothelial cells and osteoblasts co-cultured, including celladhesion, spreading, proliferation, as wel as the protein secretion of vascular endothelial growth factor and basic fibroblast growth factor from co-culture system in vitro. METHODS:Human umbilical vein endothelial cells and osteoblastic cells (MG63) were utilized in this study. cells from passage 3 were used for preparation of the cel-scaffold constructs. After placed in 24-wel plate at a ratio of 2:1, human umbilical vein endothelial cells and MG63 cells were seeded onto strontium-doped calcium polyphosphate, calcium polyphosphate and hydroxyapatite scaffolds and co-cultured for 7 days. The vascular endothelial growth factor and basic fibroblast growth factor protein levels were determined through a double ligand enzyme-linked immunosorbent assay. The colorimetric 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay was performed to quantify the effect of scaffolds on cellproliferation. RESULTS AND CONCLUSION:Compared with those on calcium polyphosphate and hydroxyapatite scaffolds, cells on strontium-doped calcium polyphosphate scaffolds attached and spread better with a significantly improved cellproliferation. More importantly, the vascular endothelial growth factor and basic fibroblast growth factor expressions were significantly higher in the strontium-doped calcium polyphosphate group than the other two groups (P<0.05), indicating strontium-doped calcium polyphosphate can up-regulate levels of vascular endothelial growth factor and basic fibroblast growth factor proteins.
ABSTRACT
This study was intended to investigate the crosslinking characteristics of a new crosslinking agent-oxidized sodium alginate (ADA), which might provide an ideal biological crosslinking reagent for the construction of soft tissue bioprostheses. Glutaraldehyde and genipin, which have been typically used in developing bioprostheses, were used as controls. The porcine aortas were treated by these three crosslinking agents for 15 min to 72 h and the fixation index was determined. Subsequently, the mechanical property and cytocompatibility of fixed tissues were also tested. The results indicated that fixed tissues by ADA were comparable as glutaraldehyde and superior to genipin controls in fixative efficiency. It was also found that tissues fixed by ADA were comparable as genipin and superior to glutaraldehyde controls in cytocompatibility and were similar to natural tissues in mechanical property. The results of in vitro study demonstrated that ADA could be a promising crosslinking reagent for biological tissue fixation.
Subject(s)
Animals , Alginates , Chemistry , Pharmacology , Aorta , Cell Biology , Metabolism , Biocompatible Materials , Metabolism , Cross-Linking Reagents , Chemistry , Pharmacology , Extracellular Matrix , Metabolism , Glucuronic Acid , Chemistry , Pharmacology , Hexuronic Acids , Chemistry , Pharmacology , Swine , Tissue Engineering , Methods , Tissue Fixation , Tissue ScaffoldsABSTRACT
BACKGROUND: Strontium-doped calcium polyphosphate (SCPP) is a new type of bone repair materials with good biocompatibility and controlled degradation. The preliminary studies of our group indicate their role in promoting angiogenesis,but its mechanism is unclear.OBJECTIVE: By co-culturing osteoblasts ROS17/2.8 with SCPP in vitro to observe cell proliferation and the secretion of vascular endothelial growth factor (VEGF).DESIGN, TIME AND SETTING: A contrast study was performed at the Laboratory of Tissue Engineering of Sichuan University from October 2008 to June 2009.MATERIALS: A series of calcium polyphosphate (CPP) respectively containing 0%, 1 %, 2%, 5%, 8%, and 10% Sr~(2+) were prepared. ROS17/2.8 osteoblastic cell strain was provided by Laboratory of Transplantation Immunity and Transplantation Engineering, West China Hospital, Sichuan University.METHODS: ①Preparation of cell scaffold complexes: The materials were placed in 24-well plates, then 300 μL cell suspension with a concentration of 2×10~7 cells/Lwas inoculated into each hole. These complexes were cultured for 14 days and the liquid was changed every two days. ②These complexes were measured by MTT assay to observe the proliferation of osteoblasts on the 1~(st), 3~(rd), 5~(th), 7~(th), 10~(th) and 14~(th) days, respectively. ③ The centrifugal supernatant of the complex cultured for seven days was measured by ELISA assay to check the secretion of VEGF.MAIN OUTCOME MEASURES: The proliferation of osteoblastic cells on SCPP and CPP was observed. The amount of VEGF protein secreting from osteoblastic cells was detected.RESULTS: The results of MTT showed that, compared with the CPP group, SCPP groups could promote the proliferation of osteoblasts, and 8% SCPP group was the best; ELISA results showed that, compared with the CPP group, SCPP groups could increase the amount of VEGF protein secretion, of which the promoting role of 8% SCPP was the most obvious (P < 0.05).CONCLUSION: When cultured with osteoblasts, SCPP can promote cell proliferation, and can significantly increase the secretion of VEGF; moreover, 8% SCPP is the best, which reveals a certain mechanism of its promoting angiogenesis.