E. Sasaki (Hirosaki, JP)
Hirosaki University Graduate School of Medicine Department of Orthopedic SurgeryPresenter Of 1 Presentation
12.1.5 - Systemic Administration of High Mobility Group box-1 Peptide Repaired Murine Osteochondral Defect
Abstract
Purpose
Autologous chondrocytes implantation is a common procedure for large cartilage defect, which takes two-time surgeries and high-cost cell processing centers. Recently, we revealed that the systemic administration of high mobility group box-1 peptide (HMGB1-44) has a potential to accelerate scarless tissue regeneration via circulating mesenchymal cells. The purpose of this study was to investigate the effects of HMGB1-44 peptide to murine osteochondral defect.
Methods and Materials
HMGB1-44 peptides were intravenously administered (100 μg in 100 μL saline) 2 times a week into 8-week-old adult male mice with 0.5 mm depth and 0.5mm width osteochondral defect. After 4 weeks administration, Wakitani score was compared with vehicle (100μl saline) group. Furthermore, to reveal the mechanism, we evaluated induced tomato-fluorescent-positive cells in blood and defect sites of wild type mice parabiotically paired with PDGFRa-Cre; ROSAtdTomato mice. Also, the immunohistochemistry with Col1, Co2, Sox9, and Acan were evaluated at 12 weeks after osteochondral injury. Finally, to investigate the relationship with Cxcr4/Cxcl12 axis, efficacy of AMD3100, Cxcr4-specific antagonist, was examined.
Results
While saline administration resulted in a failure of hyaline cartilage regeneration and deposition of fibrous scar tissues (Fig.1), HMGB1-44 peptide administration significantly induced the regeneration of the hyaline cartilage stained with safranin-O, and their Wakitani score were higher than those of vehicle group. The accumulation of tomato-fluorescent-positive cells were higher in blood and defect sites in HMGB1-44 group. Also, tomato-fluorescent-positive cells marked higher Col2, Sox9, and Acan and lower col1 expressions (Fig2). Finally, the accumulation of tomato-fluorescent-positive cells reduced by AMD3100 and cartilage regeneration with hyaline cartilage was cancelled by AMD3100.
Conclusion
HMGB1-44 peptide induced circulating mesenchymal cells, which expressed Sox9, Col2 and Acan in osteochondral defect sites, via CXCR4/CXCL12 axis. Intravenous administration of HMGB1-44 peptide induced hyaline cartilage regeneration and repaired murine osteochondral defect