BMP-2 plasmid DNA-loaded chitosan films - A new strategy for bone engineering.

OBJECTIVES: Bone defects are common in every area of medicine and remain a clinical challenge. Tissue engineering has led to promising new strategies in accelerating bone repair. Bone morphogenetic proteins (BMPs) play crucial roles in bone regeneration, but are required in supra-physiological doses, which are expensive and produce severe side effects.

METHODS: To address these issues, we prepared BMP-2 plasmid DNA-loaded chitosan films, and examined their effects on mouse osteoblast-like MC3T3-E1 cell morphology, proliferation, and runt-related transcription factor 2 (RUNX2) expression. In vivo testing was performed using calvarial critical-sized defects and histomorphometry in 36 Sprague-Dawley rats. Unloaded chitosan films and empty defects served as controls.

RESULTS: In contrast to the controls, cells grown on BMP-2 plasmid DNA-loaded chitosan films had well established filopodia and lamellipodia, significantly higher proliferation 2, 4, and 6 days post-seeding (P ≤ 0.05), and higher nuclear RUNX2 expression. In vivo, new bone growth was significantly greater in the BMP-2 group than in the control groups at 4, 8, and 12 weeks (P ≤ 0.01).

CONCLUSIONS: Based on our study findings, BMP-2 plasmid DNA-loaded chitosan films provide an effective strategy for GBR, combining cellular compatibility with biocapability in vivo.