C-and N-terminal telopeptides of type I collagens, osteocalcin and bone-specific alkaline phosphatase used for the early diagnosis of bone nonunion / 中国组织工程研究

ABSTRACT

BACKGROUND:Detecting the serum levels of biochemical markers to assess bone fractures is simple, mini-invasive and specific. Thereafter, to predict bone nonunion by choosing an appropriate marker has become a hotspot. OBJECTIVE:To establish an animal model of bone nonunion and explore the changing rules of the biochemical markers during the process of nonunion. METHODS:Twenty New Zealand white rabbits aged 5-6 months were enrol ed and divided into two groups. In bone defect group, a 15-mm length of bone (including the periosteum) was removed from the left mid-radius, and the medul ary cavities were closed with bone wax. In bone fracture group, the mid-radius was fractured. X-ray examination was taken and blood samples were extracted preoperatively and at 2, 3, 4, 5, 6, 7, 8, 10, and 12 weeks after surgery. The serum levels of osteocalcin and bone-specific alkaline phosphatase (BSAP) as markers of bone formation, and C-terminal telopeptide of type I col agen (CTX), N-terminal telopeptide of type I col agen (NTX), and tartrate-resistant acid phosphatase 5b (TRACP 5b) as markers of bone resorption, were measured using biotin double-antibody sandwich ELISA. RESULTS AND CONCLUSION:In the bone defect group, the bone metabolism was at a high level, suggesting that the early diagnosis of bone nonunion depends on several biochemical indicators. In the bone defect group, the serum level of CTX peaked at 5 weeks, and the serum levels of osteocalcin, BSAP and NTX decreased obviously at 4 or 5 weeks, while the serum TRACP 5b concentration did not change significantly, indicating that al above markers except TRACP 5b sensitively reflect the bone turnover in vivo. Further studies are needed to determine whether systematic monitoring of the biochemical markers can reflect the bone turnover effectively and can be used for the early diagnosis of nonunion in the rabbit model.