Injectable gellan gum hydrogels with autologous cells for the treatment of rabbit articular cartilage defects

In this work, the ability of gellan gum hydrogels coupled with autologous cells to regenerate rabbit full-thickness articular cartilage defects was tested. Five study groups were defined: (a) gellangumwith encapsulated chondrogenic predifferentiated rabbit adipose stem cells (ASCþGF); (b) gellan gum with encapsulated nonchondrogenic predifferentiated rabbit adipose stem cells (ASC); (c) gellan gum with encapsulated rabbit articular chondrocytes (AC) (standard control); (d) gellan gum alone (control); (e) empty defect (control). Fullthickness articular cartilage defects were created and the gellangum constructs were injected and left for 8 weeks. The macroscopic aspect of the explants showed a progressive increase of similarity with the lateral native cartilage, stable integration at the defect site, more pronouncedly in the cell-loaded constructs. Tissue scoring showed that ASCþGF exhibited the best results regarding tissue quality progression. Alcian blue retrieved similar results with a better outcome for the cell-loaded constructs. Regarding real-time PCR analyses, ASCþGF had the best progression with an upregulation of collagen type II and aggrecan, and a downregulation of collagen type I. Gellan gum hydrogels combined with autologous cells constitute a promising approach for the treatment of articular cartilage defects, and adipose derived cellsmayconstitute a valid alternative to currently used articular chondrocytes.J. T. Oliveira acknowledge the Portuguese Foundation for Science and Technology (FCT) for his grant (SFRH/BD17135/2004). The authors thank the medical and technical staff of the Institute for Biomedical Sciences Abel Salazar (ICBAS) of the University of Porto, Portugal and the Institute for Health and Life Sciences (ICVS) of the University of Minho, Portugal. The authors also thank Dr. Patricia Malafaya, Cristina Correia, and Rui Pereira, for their help with the histological scoring. This work was carried out under the scope of the European NoE EXPERTISSUES, and partially supported by the European Project HIPPOCRATES