2008 Annual Meeting Abstracts
QUANTITATIVE ANALYSIS OF GENE EXPRESSION AND PRODUCTION OF MULTIPLE GROWTH FACTORS IN THE EARLY TENDON HEALING STAGE: IMPLICATIONS IN MOLECULAR THERAPY
Paul Liu, MD1, Jin Bo Tang1, Chuan Hao Chen, MD2.
1Roger Williams Medical Center, Providence, RI, USA, 2Affiliated Hospital of Nantong University, Nantong, China.
Objective: Expression of different growth factor genes during healing process of intrasynovial tendons is not clearly understood currently. In an in vivo model, we investigated expression of a number of growth factor genes at different time-points in the early healing period.
Design and Methods: 28 white leghorn chickens were used. The flexor digitorum profundus (FDP) tendon of the long toes of both feet of the chickens were transected and repaired surgically. Postoperatively, at 3, 7, 9 days and 2, 3 weeks, tendon samples were harvested and underwent standard procedures of RNA extraction, reverse transcription to cDNA, and real-time PCR reactions to examine the levels of gene expression, or were stained with antibodies to growth factors. Six growth factors (VEGF, PDGF-B, CTGF, TGF-beta, bFGF, and IGF-1) were studied.
Outcome Measures: Real-time PCR analysis and immunohistochemical staining.
Results: Genes of TGF-beta and CTGF expressed strongly at all time-points in the early period. PDGF-B and bFGF genes expressed at low levels at all study time-points. Expression of IGF-1 and VEGF genes was at moderate levels. Expression of all growth factors peaked at day 3 except for bFGF and PDGF-B. Immunohistochemical staining confirmed production of these growth factors were consistent with the changes of gene expression.
Conclusions: bFGF and PDGF-B express very minimally during the early healing period. In contrast, TGF-beta and CTGF expressed very strongly. Future work towards molecular modulation of gene expression to up-regulate bFGF or PDGF-B expression likely enhance the healing; down-regulation of TGF-beta or CTGF expression likely decrease the adhesion formation.