Involvement of MAGP1 in β-TCP enhanced bone regeneration

Microfibril-associated glycoprotein-1 (MAGP1) is a small molecular weight, ubiquitous component of the fibrillin-rich microfibrils that found in the extracellular matrix. Inactivation of MAGP1 results in a bleeding diathesis and an altered wound healing response in bone and skin. Beta-tricalcium phosphate (β-TCP) is widely used in clinical orthopedic surgery due to its high biodegradability, osteoconductivity, easy manipulation and lack of histotoxicity. In this study, we aimed to understand the differential expression of MAGP1 in bone tissue implanted with β-TCP. Following the extraction of premolars and subsequent bone healing,β-TCP was implanted into the artificial osseous defect of dog mandibles. Bone tissue specimens were collected at 4 and 7 days after implantation. Total RNA was isolated from bone tissue, and gene expression profiles were analyzed using microarray technology. MAGP1 mRNA was up-regulated at days 4 and 7 in β-TCP-implanted tissues compared to the controls. Real-time PCR was used to confirm the mRNA levels. Immunohistochemical analysis revealed a higher expression in MAGP1 protein at day 7 in b-TCP-implanted tissues compared to the control. These results suggest that MAGP1 might be involved in the early stage of β-TCP enhanced bone regeneration.