The effect of mesenchymal stem cells and exosomes on cartilage viability

THE EFFECT OF MESENCHYMAL STEM CELLS AND EXOSOMES ON CARTILAGE VIABILITY Aim: The aim of this study is to investigate experimentally the effects of nanofat, mesenchymal stem cells and exosomes, which are thought to help preserve the tissue properties and viabilities in the long term at the sites where cartilage grafts are placed, in a histochemical and immunohistochemical manner. Material and Method: 24 Wistar albino rats were included in the study. Cartilage grafts harvested from rat auricles were implanted onto the interscapular area and treated with adipose derived stem cells (ADSC), ADSC-derived exosomes, and nanofat. Groups consisting of 8 rats each were followed up for 4, 12, and 24 weeks. At the designated time points, the rats were euthanized under general anesthesia using cervical dislocation method, and the implanted cartilage grafts were collected for histochemical and immunohistochemical examination. Results: While there was no statistically significant difference in collagen II H-scores between the groups treated with nanofat and ADSC compared to the control group (p>0.05), a statistically significant difference was observed in the exosome at group 2d (p=0.035). Groups 2d and 3d exhibited significant differences in collagen II H-scores compared to group 1d (p=0.048, p=0.018). Although improvement was observed in collagen II H-scores of the ADSC group, statistically significant results could not be obtained (p>0.05). Histochemical analysis revealed that viability contributed positively in all groups at 24 weeks; however, this effect was observed to start before 4 weeks in ADSC, and after 4 weeks in the exosome group. Despite starting later, the exosome-treated group was found to be more effective at 24 weeks in terms of histochemical staining and collagen II H-scores. Conclusion: It was determined that all groups did not induce cartilage toxicity, and they all had a positive effect on viability and chondrogenesis. The exosome group was found to be the most effective method among the applications, and its effect started after 4 weeks; although ADSC showed an effect before 4 weeks, it was not as effective as exosome application in the long term. In surgical procedures involving cartilage grafts, the addition of exosomes can contribute to surgical success. Keywords: Cartilage graft, exosome, adipose-derived mesenchymal stem cell, nanofat