Analysis of genetic regulation and cytokine expressions of distraction osteogenesis reconstruction for cleft palate.

Abstract

Because cleft palate (CP) is one of the most common congenital deformities, surgeons have tried for longtime to achieve an ideal reconstruction of the palatal bone defects and restoration of muscle attachments. In this study, a new CP model on rhesus was established and corrected by an approach of distraction osteogenesis (DO), and then quantitative studies of regulation of osteogenesis genes and expression of alkaline phosphatase (ALP), insulin-like growth factor-I (IGF-I), osteopontin (OPN), and osteocalcin (OC) in different phases of new bone formation were preformed. The CP models (23 animals) were established surgically. In the experimental group (21 animals), the tissue defects were repaired by means of DO at the rhythm of 0.4 mm twice per day. The specimens were retrieved in 1, 2, 4, 6, 8, 12, and 24 weeks (3 animals each) after completion of distraction. The IGF-I, ALP, OPN, and OC messenger RNA (mRNA) were detected by real-time reverse transcription polymerase chain reaction, and their proteins were then analyzed by enzyme-linked immunosorbent assay tests. The results are compared with those of the experimental control and empty control groups (2 animals each). In the distraction gap, the mRNA and protein expressions levels of IGF-I and ALP were both highly upregulated and reaching apex in the early phase of new bone formation. Otherwise, the mRNA and protein expressions of OPN and OC demonstrated high level during intermediate and later remodeling stages. These results suggest that the reconstruction of CP bone defect by means of DO could get definitely intramembraneous new bone formation and eventually quite normal bone structure via consecutive remodeling in situ.