Mesenchymal stem cells from adipose tissue and plasma rich in growth factors in degenerative joint dissease in dogs

Abstract

identify at what specific point the healing processes diverge between the two mice strains. Methods: Two groups of MRL/MpJ and C57BL/6 male mice (5 weeks of age; n1⁄4 6 per time point) were used in the study. A custommade depth controlled needle (26 gauge) was used to introduce a full thickness cartilage defect into the femoral groove of the left knee. At 4 and 6 weeks post-surgery, the respective groups were euthanized and the legs were dissected out and fixed in 10% NBF. Using a 9.4 T magnet and a quadrature coil, samples underwent ex vivo magnetic resonance imaging using a RARE sequence (Repetition time 1⁄4 2000 ms; Echo time 1⁄4 7.6 ms; FOV 1⁄41.92; Matrix 1⁄4 256). After imaging, samples were decalcified using 10% EDTA, embedded in paraffin, and sectioned at 7 um thickness. Sections were then stained with Safranin-O and immunohistochemistry (IHC) was performed using the anti-mouse Ly-6A/E (also known as Stem Cell Antigen1; Sca-1). Results: MRI scans at 4 weeks showed higher signal intensity at the cartilage compared to those scanned at 6 weeks (Fig1). There were no observable differences between strains at each time point. Safranin-O staining of the C57 sections at the 4 weeks, showed lower proteoglycan content than the MRL at the same time point. Defects were observable in C57mice at all time points, but were not observed inMRLmice (Fig2). However, tissues within the MRL defect were not identical with the surrounding tissues, in specific regards to proteoglycan content, matrix structure, and chondrocyte orientation. Also of interest, it was observed that Sca-1 positive cells were enriched within the C57 defect, but were not found within the MRL defect (Fig2). Conclusion: In this study, we sought to characterize the early stages of endogenous cartilage repair that occurs in MRL/MpJ mice using both a non-invasive imaging technique (MRI) and tradition histological methods. Interestingly, MRI scans revealed that at 4 weeks post injury, there were no observable differences between C57 and MRL mice, though the Safranin-O stains did show increased cellularity in MRL samples at the defect compared to C57. Furthermore, the scarcity of Sca1+ cells in MRL samples was surprising as the Safranin-o stains had revealed the superior healing and increased cellularity of the defect compared to the C57’s. A possible explanation could be that the recruitment of Sca-1 cells in the MRL's occurs much earlier than the time points used in this study. This would explain the lack of Sca-1 cells as well as the increased cellularity and structural organization at the defects of the MRL's compared to the C57’s. Future efforts will be focused on earlier time points than what was used in the present study. 212 MESENCHYMAL STEM CELLS FROM ADIPOSE TISSUE AND PLASMA RICH IN GROWTH FACTORS IN DEGENERATIVE JOINT DISSEASE IN DOGS B. Cuervo Serrato , M. Rubio Zaragoza , J. J. Sopena Juncosa , R. Cugat Bertomeu , J. M. Dominguez Perez , M. Morales Doreste , A. Tarrago Riverola , D. Najera Lopez , J. M. Vilar Guereno , J. M. Carrillo Poveda . y Fundacion Garcia Cugat, Barcelona, Spain; Univ. CEU Cardenal Herrera, Valencia (Alfara del Patriarca), Spain; ARTROSOPIA GC. Hosp. QUIRON, Barcelona, Spain; Univ. de Cordoba, Cordoba, Spain; Univ. de Las Palmas, Las Palmas de Gran Canaria, Spain; CV Sagrada Familia, Barcelona, Spain; CV Granollers, Barcelona, Spain