Aberration test of injectable tissue engineered bone carriers with algin-gelatin blend system / 中国组织工程研究

ABSTRACT

BACKGROUND: Utilizing tissue engineering technique, various gel systems are served as scaffolds to repair bone defect. The scaffolds should have features of nontoxic and no teratological effects to the body. OBJECTIVE: To observe the effect of sodium alginate-gelatin/osteoblast gel on chromosomal pattern aberration in rabbits. DESIGN, TIME AND SETTING: The in vivo material animal experiments were conducted at the Beijing Shijitan Hospital and Department of Histology and Embryology, Peking University Health Science Center from October 2007 to March 2008. MATERIALS A total of 12 New Zealand rabbits, aged 2 months, with clean grade, were randomly divided into 2 groups. The experimental group contains 4 female and 4 male rabbits, and the remaining 4 females were served as the control group. Sodium alginate dried powder were purchased from Sigma, USA, and the gelatin dried powder were supplied by Liidao Company, Hebei, China. METHODS: Following numbering, bone marrow was collected from 12 rabbits. Bone marrow stromal stem cells (BMSCs) were isolated by the density gradient centrifugation, and then in vitro cultured with osteoblast inductor. Osteoblasts following passage were an order of magnitude of 10~7. Bright pink gelatiniform liquid with mass ratio of sodium alginate and gelatin at ratio of 23 was prepared. Rabbit osteoblasts with final concentration of 5×10~9/L were mixed with CaCb solution to form fruit jelly-shaped sodium alginate-gelatin/osteoblast gel. Critical-sized calvarial defects were created in diameter of 1.5 cm in 12 rabbits. After 1 week, cell/scaffold complex (0.5 mL) was implanted to repair the bone defect in the experimental group. There was no treatment in the control group. MAIN OUTCOME MEASURES: The change of chromosomal pattern was observed at 3 months following reparation. RESULTS: No Chromosome somatotype aberration was found in 100 metaphases in the experimental group. From 400 metaphases of the control group, 4 abnormal cells were found, with 1% chromatid-type aberration ratio. Meantime, 12 abnormal cells in 800 metaphases of the control group were found, with 1.5% chromatid-type aberration ratio. The numerical value was within the normal range. Chromosome karyotype analysis: the chromosome number of each experimental rabbit was 2n=44, karyotype of the control rabbit was 44, XX, which was normal female; or 44, XY, normal male, no abnormal was found. The female rabbit in the experiment group was 44, XX, no abnormal was seen. CONCLUSION: From the cytogenetoxicity point of view, sodium alginate-gelatin/osteoblast gel is safe in repairing bone defects.