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Session: Joints
Session starts: Friday 25 January, 13:00
Presentation starts: 13:45
Room: Lecture room 535

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Martina Puricelli (LifeTec Group)
Edoardo Andreini ()
Dave Wanders (LifeTec Group)
Linda M. Kock (LifeTec Group)

Abstract:
Ex vivo models represent an inexpensive and controllable way to explore osteochondral regeneration. We have developed an ex vivo osteochondral culture platform and using this we have shown that is possible to maintain physiological cartilage viability, matrix tissue content and structure for 56 days in culture [1]. As mechanical loading is known to be essential for the maintenance of osteochondral tissue viability and properties, the next step was to incorporate mechanical loading in our culture platform. Therefore, the aims of this study were to 1) adapt the platform such that we can apply mechanical loading to ex vivo porcine osteochondral biopsies in culture and 2) investigate the effect of a physiological mechanical loading regime on ex vivo cultured biopsies in a long-term study. We designed a platform that can simultaneously compress 6 osteochondral plugs through the vertical displacement of a linear actuator. In a custom designed graphical interface, we can set frequency, amplitude and intermittence of the stimulation. In a first study, we tested two different compression rates: 5% and 10% at 1Hz for 4 hours on, 20 hours off, during 6 weeks of culture. An unloaded group served as control. The mechanical properties of the cartilage tissue of loaded and unloaded groups were assessed through stress relaxation tests at day 0, and after 6 weeks of culture. The biological properties of the cartilage were evaluated through thionin staining for glycosaminoglycans (GAGs), quantification of GAG content and a viability (MTT) assay. We demonstrated that the designed platform can successfully stimulate osteochondral samples in a controlled, sterile and accurate manner. Preliminary results of the long-term culture showed that mechanical loading did preserve GAG content over time, while GAG content in unloaded samples decreased slightly over time. MTT staining shows that metabolic activity is preserved during the culture period similarly in all groups. In conclusion, this platform represents a valuable tool that can better preserve the osteochondral tissue viability and content during long-term culture by using relevant mechanical loading regimes. This offers opportunities for evaluating therapies and treatments for cartilage and/or bone repair in a relevant environment, mimicking the in vivo situation. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under Marie Sklodowska-Curie grant agreement No 721432. References: [1] Schwab, A. et al, 2017. ALTEX - Alternatives to animal experimentation. [2] ML Vainieri, et al, 2018, Acta Biomaterialia.