Evaluating Bone Regeneration and Angiogenesis in 1393B3 Bioactive Glass Scaffolds

    Large bone defects from trauma or diseases can be reconstructed by bone grafts and/or biomaterials. Our previous investigation showed that bioactive borate glass 1393B3 supported greater bone formation and complete hydroxyapatite conversion in bone defects compared to 1393 or 1393B1 glass.  Objectives: This study was to evaluate 1393B3 glass scaffolds in trabecular, fibrous, and unidirectional orientations with and without copper for bone regeneration, angiogenesis and hydroxyapatite conversion. Methods: 26 Sprague-Dawley rats were to create critical sized defects within the calvarium.  The defects were filled with 1393B3 scaffolds in trabecular, fibrous, and unidirectional orientations with and without copper.  45s5 bioactive glass was a positive control.  The samples were harvested after 12 weeks and stained with H&E to evaluate bone regeneration, von Kossa to estimate hydroxyapatite conversion and PAS to evaluate blood vessel area. Results: Bone regeneration was mostly osteoconductive; however, all scaffold types had osteoinductive bone growth.  Total bone regeneration was 33% for trabecular, 31% for copper trabecular, 23% for unidirectional, 26% for copper unidirectional, 15% for fibrous, 32% for copper fibrous, and 19% for 45s5. The trabecular and copper fibrous scaffolds were significantly higher in bone regeneration (p=0.009) than the fibrous scaffold.  The von Kossa-positive area for estimation of hydroxyapatite conversion was 22% for trabecular, 21% for copper trabecular, 35% for unidirectional, 24% for copper unidirectional, 48% for fibrous, 36% for copper fibrous, and 33% for 45s5.  The fibrous scaffold had significantly higher estimated hydroxyapatite conversion than copper unidirectional (p=0.04) and copper trabecular scaffolds (p=0.036).  Blood vessels infiltrated into all bioactive glasses. There were no significant statistical differences between groups. Conclusions: Trabecular scaffolds have a greater capacity for bone regeneration and osteoinduction which make them promising for bone repair.  Copper appears to increase osteoconduction in fibrous scaffolds. Funded by the UMKC Summer Scholars Program and DOD/USA Med Research AQQ-Activity (W81XWH-08-1-0765).