Effectiveness of tissue engineered chitosan-gelatin composite scaffold loaded with human platelet gel in regeneration of critical sized radial bone defect in rat

Although many strategies have been utilized to accelerate bone regeneration, an appropriate treatment strategy to regenerate a new bone with optimum morphology and mechanical properties has not been invented as yet. This study investigated the healing potential of a composite scaffold consisting of chitosan (CS), gelatin (Gel) and platelet gel (PG), named CS-Gel-PG, on a bilateral critical sized radial bone defect in rat. Eighty radial bone defects were bilaterally created in 40 Sprague-Dawley rats and were randomly divided into eight groups including untreated, autograft, CS, Gel, CS-PG, Gel-PG, CS-Gel, and CS-Gel-PG treated defects. The bone defects were evaluated clinically and radiologically during the study and their bone samples were assessed by gross and histopathology, histomorphometry, CT-scan, scanning electron microscopy, and biomechanical testing after 8 weeks of bone injury. The autograft and CS-Gel-PG groups showed significantly higher new bone formation, density of osseous and cartilaginous tissues, bone volume, and mechanical performance than the defect, CS and Gel-PG groups (P ˂ 0.05). In addition, bone volume, density of osseous and cartilaginous tissues, and numbers of osteons in the CS-Gel-PG group were significantly superior to the CS-PG, CS-Gel and Gel groups (P ˂ 0.05). Increased mRNA levels of alkaline phosphatase, runt-related transcription factor 2, osteocalcin, collagen type 1 and CD31, vascular endothelial growth factor as osteogenic and angiogenic differentiation markers were found with the CS-Gel-PG scaffold by quantitative real-time PCR in vitro after 30 days of culturing on bone marrow-derived mesenchymal stem cells. In conclusion, the healing potential of CS-Gel scaffold embedded with PG was comparable to autografting and therefore, it can be offered as an appropriate scaffold in bone tissue engineering and regenerative applications.