Injectable Gellan Gum Hydrogels With Autologous Cells for theTreatment 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.