The success of fracture healing relies on coordinated overlapping cellular and molecular events. 10-15% of cases worldwide result in delayed healing, non-union or pseudarthrosis. Therefore, analysis of molecular and cellular healing events is important to discover new therapeutic attempts in clinical research. Besides, engineering a blueprint of differential regulation throughout physiological healing is essential to specify phase-specific markers. Such undercarriage will pinpoint irregular gene expression, whether chronological, temporal or functional. This study analyzed the healing progression of standard closed femoral fracture in C57BL/6N (age = 8 weeks) wild type male mice model. Fracture callus was assessed at days 3, 7, 10, 14, 21, and 28 post fracture by microarray and histological analysis. Results revealed increased bone mineralization with healing progression and bony bridging was seen by day 28. In-depth analysis of bone matrix mineralization showed changes in collagen orientation and osteocytes morphology with healing progression. Differential expression analysis followed by gene ontology associated genes with angiogenesis, ossification, extracellular matrix regulation, immune response, mitochondrial, and ribosomal activity. However, the overlapping genes between consecutive time points were not addressed before. This thesis compared consecutive time points to study the overlapping genes in correlation to healing events. In accordance to previous reports, this thesis showed the importance of angiogenesis, ossification, immune response, and extracellular matrix regulation leading to successful healing. However, the individual role of mitochondrial and ribosomal genes in bone regeneration remain unknown. Differential analysis in this study showed drastic downregulation among the mitochondrial and ribosomal genes during the early phase of healing. Further, histological evaluation of mitochondrial marker (GPX1) and ribosomal marker (UBB) showed patches of positive stain in osteocytes and blood vessels vicinity during the course of healing. In summary, this study shows the importance of mitochondrial and ribosomal genes besides angiogenesis, ossification, extracellular matrix, and immune response to reach the successful bony consolidation. Moreover, this mouse fracture model can be used as a template to identify specific molecular mechanism of fracture healing.
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