PhD, University of Cincinnati, 2009, Engineering : Biomedical Engineering

Tracking real-time changes in Col1 and Col2 gene expression could speed up the FTE process and could lead to new strategies to create zonal insertions in repair tendons. Hence double transgenic mice with fluorescent promoters for Col1 and Col2 gene expression were created and used to examine natural healing of patellar tendons, development of knee structures and the mechanical response of primitive MSCs as well as specialized chondrocytes and fibroblasts.The natural healing study sought to determine how full thickness, mid-substance punch defect injuries affect spatial and temporal patterns of Col1 and Col2 gene expression and biomechanics compared to age-matched, normal patellar tendons. Col1 expression in injured tendons was highest at two weeks after injury. No detectable Col2 gene expression was seen in the mid-substance healing wound site at any time point. Natural healing resulted in inferior repair properties at both 4 weeks and 6 weeks post injury compared to contralateral sham and age-matched tendons. Monitoring fluorescent changes in murine knees from embryonic through early post-natal development indicates that Col2 expression precedes Col1 expression. There were temporal and spatial changes in the expression of two related growth factors, TGF-β1 and BMP-2, and their downstream markers, pSmad1,5,8 and pSmad2,3 respectively. Exposing specialized and primitive cell-scaffold constructs to dynamic compressive strains produced temporal changes in gene, protein expression and biomechanics. Compression of chondrocyte-agarose scaffolds significantly increased ECFP fluorescence, Col2 mRNA expression, type II collagen content and aggregate modulus. ECFP fluorescence and Col2 mRNA expression were found to be positively correlated. Compression of MSC-agarose constructs significantly increased ECFP fluorescence, type II collagen content and aggregate modulus. Finally, 28 days of compressive stimulation of fibroblast-agarose constructs produced significant decrease (open full item for complete abstract)

Committee: David Butler PhD (Committee Chair); Jason Shearn PhD (Committee Member); Marepalli Rao PhD (Committee Member); Shawn Hunter PHD (Committee Member) Subjects: Biomedical Research